So, for my day job I'm working on a circuit board design to replace
something which features a heatsink made from aluminum angle. It's 1" x
1" x 1/4", with nice square corners everywhere (radius 0.02").

Up to now I've been blithely assuming that this is an off-the-shelf item
that I can get anywhere -- but it looks like it may be harder to get than
that. Worse, I'd really like to extend the heat sink another 1/2" or
even 1" under the board, while keeping the outside leg at 1".

So I want to specify something that won't have their mechanical engineers
muttering under their breath _too_ much about @#$% EEs with time on their
hands...

McMaster carries aluminum angle, but it describes the inside corner and
the inside ends of the legs as "rounded", without saying what the radius
is. I can handle a radius on the inside corner, but that radius on the
leg takes away from area that I want touching my board. Furthermore,
McMaster only carries angle with even-length sides.

So my questions a

Is there any commonly-available aluminum angle that has corners that one
wouldn't describe as "rounded"? From who?

If I must go with rounded corners, can I expect that there is a
standard? What is it? Is there a place I might find it on the web?
(Machinery's Handbook doesn't seem to list anything like that).

Is there any commonly-available aluminum angle with uneven leg lengths?
I'm specifically looking for 1" x 1.5" x 1/4", or 1" x 2" x 1/4". From
who?

Any notion of how much it might cost to have a machine shop take a larger
angle and whack it down? These need machining anyway: they have to be
cut to length, then drilled on both webs and tapped on one -- so it would
be a case of "while it's in the machine anyway, make one or two
additional cuts". Precision is nearly nonexistent: +/- 0.05" would be
fine, and finish wouldn't be a huge issue: as long as the edges are
deburred and the cut side isn't so rough that it draws blood when handled
things would be fine; I would expect that a decent shop with even a
minimal sense of pride would insist on a much better finish than
necessary to get the job done.

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

On Wed, 21 Mar 2012 12:21:57 -0500, Tim Wescott
wrote:

So, for my day job I'm working on a circuit board design to replace
something which features a heatsink made from aluminum angle. It's 1" x
1" x 1/4", with nice square corners everywhere (radius 0.02").

Up to now I've been blithely assuming that this is an off-the-shelf item
that I can get anywhere -- but it looks like it may be harder to get than
that. Worse, I'd really like to extend the heat sink another 1/2" or
even 1" under the board, while keeping the outside leg at 1".


One of my suppliers:
http://www.yarde.com/products.html
https://www.yarde.com/catalog/class1struc.html
https://www.yarde.com/catalog/cat48.html

Yarde usually stocks the stuff shown in those pages. There's a
downloadable pdf catalog somewhere on the site that shows more
products, but not everything in it is stocked.

--
Ned Simmons

On Wed, 21 Mar 2012 12:21:57 -0500, Tim Wescott
wrote:

So, for my day job I'm working on a circuit board design to replace
something which features a heatsink made from aluminum angle. It's 1" x
1" x 1/4", with nice square corners everywhere (radius 0.02").

Up to now I've been blithely assuming that this is an off-the-shelf item
that I can get anywhere -- but it looks like it may be harder to get than
that. Worse, I'd really like to extend the heat sink another 1/2" or
even 1" under the board, while keeping the outside leg at 1".

So I want to specify something that won't have their mechanical engineers
muttering under their breath _too_ much about @#$% EEs with time on their
hands...

McMaster carries aluminum angle, but it describes the inside corner and
the inside ends of the legs as "rounded", without saying what the radius
is. I can handle a radius on the inside corner, but that radius on the
leg takes away from area that I want touching my board. Furthermore,
McMaster only carries angle with even-length sides.

So my questions a

Is there any commonly-available aluminum angle that has corners that one
wouldn't describe as "rounded"? From who?

If I must go with rounded corners, can I expect that there is a
standard? What is it? Is there a place I might find it on the web?
(Machinery's Handbook doesn't seem to list anything like that).

Is there any commonly-available aluminum angle with uneven leg lengths?
I'm specifically looking for 1" x 1.5" x 1/4", or 1" x 2" x 1/4". From
who?

Any notion of how much it might cost to have a machine shop take a larger
angle and whack it down? These need machining anyway: they have to be
cut to length, then drilled on both webs and tapped on one -- so it would
be a case of "while it's in the machine anyway, make one or two
additional cuts". Precision is nearly nonexistent: +/- 0.05" would be
fine, and finish wouldn't be a huge issue: as long as the edges are
deburred and the cut side isn't so rough that it draws blood when handled
things would be fine; I would expect that a decent shop with even a
minimal sense of pride would insist on a much better finish than
necessary to get the job done.

For an application like that, note the variation in thermal
conductivity for different grades and hardnesses of aluminum. 2024 T4
is around 120 W/m-K. 1199-O is twice that: 240 W/m-K.

I found out about the hardness/temper issue the hard way,
semi-annealing a piece of 2024 to almost double its conductivity, only
to find it drop back to the original value a couple of weeks later.

--
Ed Huntress

Tim Wescott fired this volley in
:

If I must go with rounded corners, can I expect that there is a
standard? What is it? Is there a place I might find it on the web?


Tim,
Have you checked smallparts.com? Most big-box home improvement centers
and ACE hardware carry a good selection of aluminum angles, some with
unequal legs.

I just bought 4' of 4"x4"x1/2" aluminum channel from MSC. They carry
other sizes, but few with unequal legs.

On the MSC metal, the INSIDE corners (all) are rounded (ends of the legs
as well as the crotch), but the outside corners are all square.

4x4x1/2" should be big enough for your little TO-220 sink, yes?

LLoyd

On Wed, 21 Mar 2012 13:05:05 -0500, Lloyd E. Sponenburgh wrote:

Tim Wescott fired this volley in
:

If I must go with rounded corners, can I expect that there is a
standard? What is it? Is there a place I might find it on the web?


Tim,
Have you checked smallparts.com? Most big-box home improvement centers
and ACE hardware carry a good selection of aluminum angles, some with
unequal legs.

I just bought 4' of 4"x4"x1/2" aluminum channel from MSC. They carry
other sizes, but few with unequal legs.

On the MSC metal, the INSIDE corners (all) are rounded (ends of the legs
as well as the crotch), but the outside corners are all square.

4x4x1/2" should be big enough for your little TO-220 sink, yes?

I'll take a look. It really needs to be something that's commonly
available for machine shops, though, and for the entire life of the
product -- I'm going to be specifying this to the manufacturer for whom I
am designing the board; I'm sure they'd rather not have to send out a guy
to dig through the racks at Home Depot for something that might disappear
at any moment over the next ten years or so.

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

On Wed, 21 Mar 2012 14:04:08 -0400, Ed Huntress wrote:

On Wed, 21 Mar 2012 12:21:57 -0500, Tim Wescott
wrote:

So, for my day job I'm working on a circuit board design to replace
something which features a heatsink made from aluminum angle. It's 1" x
1" x 1/4", with nice square corners everywhere (radius 0.02").

Up to now I've been blithely assuming that this is an off-the-shelf item
that I can get anywhere -- but it looks like it may be harder to get
than that. Worse, I'd really like to extend the heat sink another 1/2"
or even 1" under the board, while keeping the outside leg at 1".

So I want to specify something that won't have their mechanical
engineers muttering under their breath _too_ much about @#$% EEs with
time on their hands...

McMaster carries aluminum angle, but it describes the inside corner and
the inside ends of the legs as "rounded", without saying what the radius
is. I can handle a radius on the inside corner, but that radius on the
leg takes away from area that I want touching my board. Furthermore,
McMaster only carries angle with even-length sides.

So my questions a

Is there any commonly-available aluminum angle that has corners that one
wouldn't describe as "rounded"? From who?

If I must go with rounded corners, can I expect that there is a
standard? What is it? Is there a place I might find it on the web?
(Machinery's Handbook doesn't seem to list anything like that).

Is there any commonly-available aluminum angle with uneven leg lengths?
I'm specifically looking for 1" x 1.5" x 1/4", or 1" x 2" x 1/4". From
who?

Any notion of how much it might cost to have a machine shop take a
larger angle and whack it down? These need machining anyway: they have
to be cut to length, then drilled on both webs and tapped on one -- so
it would be a case of "while it's in the machine anyway, make one or two
additional cuts". Precision is nearly nonexistent: +/- 0.05" would be
fine, and finish wouldn't be a huge issue: as long as the edges are
deburred and the cut side isn't so rough that it draws blood when
handled things would be fine; I would expect that a decent shop with
even a minimal sense of pride would insist on a much better finish than
necessary to get the job done.

For an application like that, note the variation in thermal conductivity
for different grades and hardnesses of aluminum. 2024 T4 is around 120
W/m-K. 1199-O is twice that: 240 W/m-K.

I found out about the hardness/temper issue the hard way, semi-annealing
a piece of 2024 to almost double its conductivity, only to find it drop
back to the original value a couple of weeks later.

Fortunately the thermal design is way over-specified -- but thank you for
the reminder; I'll make sure to take hardness (and self-hardening) into
account.

I was kind of thinking that hard enough for easy machining, but no
harder, was what I wanted -- now I just need to make sure to pick an
alloy that _stays_ that way.

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

On Mar 21, 11:21*am, Tim Wescott wrote:
So, for my day job I'm working on a circuit board design to replace
something which features a heatsink made from aluminum angle. *It's 1" x
1" x 1/4", with nice square corners everywhere (radius 0.02").

Up to now I've been blithely assuming that this is an off-the-shelf item
that I can get anywhere -- but it looks like it may be harder to get than
that. *Worse, I'd really like to extend the heat sink another 1/2" or
even 1" under the board, while keeping the outside leg at 1".

So I want to specify something that won't have their mechanical engineers
muttering under their breath _too_ much about @#$% EEs with time on their
hands...

McMaster carries aluminum angle, but it describes the inside corner and
the inside ends of the legs as "rounded", without saying what the radius
is. *I can handle a radius on the inside corner, but that radius on the
leg takes away from area that I want touching my board. *Furthermore,
McMaster only carries angle with even-length sides.

So my questions a

Is there any commonly-available aluminum angle that has corners that one
wouldn't describe as "rounded"? *From who?

If I must go with rounded corners, can I expect that there is a
standard? *What is it? *Is there a place I might find it on the web?
(Machinery's Handbook doesn't seem to list anything like that).

Is there any commonly-available aluminum angle with uneven leg lengths?
I'm specifically looking for 1" x 1.5" x 1/4", or 1" x 2" x 1/4". *From
who?

Any notion of how much it might cost to have a machine shop take a larger
angle and whack it down? *These need machining anyway: they have to be
cut to length, then drilled on both webs and tapped on one -- so it would
be a case of "while it's in the machine anyway, make one or two
additional cuts". *Precision is nearly nonexistent: +/- 0.05" would be
fine, and finish wouldn't be a huge issue: as long as the edges are
deburred and the cut side isn't so rough that it draws blood when handled
things would be fine; I would expect that a decent shop with even a
minimal sense of pride would insist on a much better finish than
necessary to get the job done.

Rounded corners generally means that the stuff is extruded, you have
to go to machined billets to get squared corners. And they're
irrelevant either way for the heat sink function. The extruded
hardware store stock will machine like bubble gum, from experience.
The critical parameters for heat sinks are the surface area and heat
conductivity. You probably won't get the last with any material from
a mechanical supplier. There are heat sinks and extruded heat sink
stock available from just about any electronic supplier, with
mechanical AND thermal parameters. By the time you finish messing
about with mechanical stock, you could have had the job done using the
real deal. That's if you're doing a real job for real people and
real money. If not, carry on...

Stan

On 3/21/2012 10:21 AM, Tim Wescott wrote:
So, for my day job I'm working on a circuit board design to replace
something which features a heatsink made from aluminum angle. It's 1" x
1" x 1/4", with nice square corners everywhere (radius 0.02").

Up to now I've been blithely assuming that this is an off-the-shelf item
that I can get anywhere -- but it looks like it may be harder to get than
that. Worse, I'd really like to extend the heat sink another 1/2" or
even 1" under the board, while keeping the outside leg at 1".

So I want to specify something that won't have their mechanical engineers
muttering under their breath _too_ much about @#$% EEs with time on their
hands...

McMaster carries aluminum angle, but it describes the inside corner and
the inside ends of the legs as "rounded", without saying what the radius
is. I can handle a radius on the inside corner, but that radius on the
leg takes away from area that I want touching my board. Furthermore,
McMaster only carries angle with even-length sides.

So my questions a

Is there any commonly-available aluminum angle that has corners that one
wouldn't describe as "rounded"? From who?

If I must go with rounded corners, can I expect that there is a
standard? What is it? Is there a place I might find it on the web?
(Machinery's Handbook doesn't seem to list anything like that).

Is there any commonly-available aluminum angle with uneven leg lengths?
I'm specifically looking for 1" x 1.5" x 1/4", or 1" x 2" x 1/4". From
who?

Any notion of how much it might cost to have a machine shop take a larger
angle and whack it down? These need machining anyway: they have to be
cut to length, then drilled on both webs and tapped on one -- so it would
be a case of "while it's in the machine anyway, make one or two
additional cuts". Precision is nearly nonexistent: +/- 0.05" would be
fine, and finish wouldn't be a huge issue: as long as the edges are
deburred and the cut side isn't so rough that it draws blood when handled
things would be fine; I would expect that a decent shop with even a
minimal sense of pride would insist on a much better finish than
necessary to get the job done.

Several years ago a former customer was modernizing the design of his
product and the new design required a heat sink. I researched heatsinks
and found a company that would make any designed heatsink and in any
quantity. They also had lots of information on their web site relating
to the type of aluminum used for heat sinking. It's not off-the-shelf
aluminum.

The customer began to realize the cost of updating his product and just
killed the whole product. So, other than machining a prototype of his
heatsink, I never went any further.

I don't know if the heatsink company is still in business or not.

Guess your heatsink needs to fit the heat produces and dissipation
requirements and possibly it's low enough that common extruded would
work. You can always shorten one side of an angle.

Paul

Tim Wescott fired this volley in
:

I'm going to be specifying this to the manufacturer for whom I
am designing the board; I'm sure they'd rather not have to send out a
guy to dig through the racks at Home Depot for something that might
disappear at any moment over the next ten years or so.



In that case, check with Macklenburg-Duncan, who makes all sorts of
"standard" aluminum extrusions for consumer sales. Often as not, it's M-D
aluminum you'll find in those big-box racks.

LLoyd

On Wed, 21 Mar 2012 11:44:40 -0700 (PDT), Stanley Schaefer
wrote:


Rounded corners generally means that the stuff is extruded, you have
to go to machined billets to get squared corners.

The common square corner angle (and tubing) is extruded 6063 and the
stuff that looks like hot rolled steel angle is more often extruded
6061. But extruded in both cases.

--
Ned Simmons

On Wed, 21 Mar 2012 11:44:40 -0700, Stanley Schaefer wrote:

Rounded corners generally means that the stuff is extruded, you have to
go to machined billets to get squared corners. And they're irrelevant
either way for the heat sink function. The extruded hardware store
stock will machine like bubble gum, from experience. The critical
parameters for heat sinks are the surface area and heat conductivity.
You probably won't get the last with any material from a mechanical
supplier. There are heat sinks and extruded heat sink stock available
from just about any electronic supplier, with mechanical AND thermal
parameters. By the time you finish messing about with mechanical stock,
you could have had the job done using the real deal. That's if you're
doing a real job for real people and real money. If not, carry on...

Stan

Well, real people, real money, and a quite real expectation that the
board is going to bolt on in place of the one that it replaces -- and
their heat sink is also their mounting flange.

So yes, I could put a stock heat sink in there and inform the customer
that all they have to do is rework any unit that comes in from the field
needing a replacement board -- but I don't want to do that.

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

On Wed, 21 Mar 2012 11:59:34 -0700, Paul Drahn wrote:

On 3/21/2012 10:21 AM, Tim Wescott wrote:
So, for my day job I'm working on a circuit board design to replace
something which features a heatsink made from aluminum angle. It's 1"
x 1" x 1/4", with nice square corners everywhere (radius 0.02").

Up to now I've been blithely assuming that this is an off-the-shelf
item that I can get anywhere -- but it looks like it may be harder to
get than that. Worse, I'd really like to extend the heat sink another
1/2" or even 1" under the board, while keeping the outside leg at 1".

So I want to specify something that won't have their mechanical
engineers muttering under their breath _too_ much about @#$% EEs with
time on their hands...

McMaster carries aluminum angle, but it describes the inside corner and
the inside ends of the legs as "rounded", without saying what the
radius is. I can handle a radius on the inside corner, but that radius
on the leg takes away from area that I want touching my board.
Furthermore, McMaster only carries angle with even-length sides.

So my questions a

Is there any commonly-available aluminum angle that has corners that
one wouldn't describe as "rounded"? From who?

If I must go with rounded corners, can I expect that there is a
standard? What is it? Is there a place I might find it on the web?
(Machinery's Handbook doesn't seem to list anything like that).

Is there any commonly-available aluminum angle with uneven leg lengths?
I'm specifically looking for 1" x 1.5" x 1/4", or 1" x 2" x 1/4". From
who?

Any notion of how much it might cost to have a machine shop take a
larger angle and whack it down? These need machining anyway: they have
to be cut to length, then drilled on both webs and tapped on one -- so
it would be a case of "while it's in the machine anyway, make one or
two additional cuts". Precision is nearly nonexistent: +/- 0.05" would
be fine, and finish wouldn't be a huge issue: as long as the edges are
deburred and the cut side isn't so rough that it draws blood when
handled things would be fine; I would expect that a decent shop with
even a minimal sense of pride would insist on a much better finish than
necessary to get the job done.

Several years ago a former customer was modernizing the design of his
product and the new design required a heat sink. I researched heatsinks
and found a company that would make any designed heatsink and in any
quantity. They also had lots of information on their web site relating
to the type of aluminum used for heat sinking. It's not off-the-shelf
aluminum.

The customer began to realize the cost of updating his product and just
killed the whole product. So, other than machining a prototype of his
heatsink, I never went any further.

I don't know if the heatsink company is still in business or not.

Guess your heatsink needs to fit the heat produces and dissipation
requirements and possibly it's low enough that common extruded would
work. You can always shorten one side of an angle.

My requirements are not severe, thankfully.


--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

"Tim Wescott" wrote in message ...
So, for my day job I'm working on a circuit board design to replace
something which features a heatsink made from aluminum angle. It's 1" x
1" x 1/4", with nice square corners everywhere (radius 0.02").

Up to now I've been blithely assuming that this is an off-the-shelf item
that I can get anywhere -- but it looks like it may be harder to get than
that. Worse, I'd really like to extend the heat sink another 1/2" or
even 1" under the board, while keeping the outside leg at 1".

So I want to specify something that won't have their mechanical engineers
muttering under their breath _too_ much about @#$% EEs with time on their
hands...

McMaster carries aluminum angle, but it describes the inside corner and
the inside ends of the legs as "rounded", without saying what the radius
is. I can handle a radius on the inside corner, but that radius on the
leg takes away from area that I want touching my board. Furthermore,
McMaster only carries angle with even-length sides.

So my questions a

Is there any commonly-available aluminum angle that has corners that one
wouldn't describe as "rounded"? From who?

If I must go with rounded corners, can I expect that there is a
standard? What is it? Is there a place I might find it on the web?
(Machinery's Handbook doesn't seem to list anything like that).

Is there any commonly-available aluminum angle with uneven leg lengths?
I'm specifically looking for 1" x 1.5" x 1/4", or 1" x 2" x 1/4". From
who?

Any notion of how much it might cost to have a machine shop take a larger
angle and whack it down? These need machining anyway: they have to be
cut to length, then drilled on both webs and tapped on one -- so it would
be a case of "while it's in the machine anyway, make one or two
additional cuts". Precision is nearly nonexistent: +/- 0.05" would be
fine, and finish wouldn't be a huge issue: as long as the edges are
deburred and the cut side isn't so rough that it draws blood when handled
things would be fine; I would expect that a decent shop with even a
minimal sense of pride would insist on a much better finish than
necessary to get the job done.


"Structural" is generally 6061 and it has an inside fillet whereas "architectural" is generally 6063 and has sharp corner.

That said, your problem probably isn't going to be finding it with sharp corners, rather, it's going to be finding it in your desired (1/4) in wall thickness.

Suggest try this link you just might just find something...

http://tinyurl.com/6vwjdzj

On Wed, 21 Mar 2012 15:28:34 -0700, PrecisionmachinisT wrote:

"Tim Wescott" wrote in message
...
So, for my day job I'm working on a circuit board design to replace
something which features a heatsink made from aluminum angle. It's 1"
x 1" x 1/4", with nice square corners everywhere (radius 0.02").

Up to now I've been blithely assuming that this is an off-the-shelf
item that I can get anywhere -- but it looks like it may be harder to
get than that. Worse, I'd really like to extend the heat sink another
1/2" or even 1" under the board, while keeping the outside leg at 1".

So I want to specify something that won't have their mechanical
engineers muttering under their breath _too_ much about @#$% EEs with
time on their hands...

McMaster carries aluminum angle, but it describes the inside corner and
the inside ends of the legs as "rounded", without saying what the
radius is. I can handle a radius on the inside corner, but that radius
on the leg takes away from area that I want touching my board.
Furthermore, McMaster only carries angle with even-length sides.

So my questions a

Is there any commonly-available aluminum angle that has corners that
one wouldn't describe as "rounded"? From who?

If I must go with rounded corners, can I expect that there is a
standard? What is it? Is there a place I might find it on the web?
(Machinery's Handbook doesn't seem to list anything like that).

Is there any commonly-available aluminum angle with uneven leg lengths?
I'm specifically looking for 1" x 1.5" x 1/4", or 1" x 2" x 1/4". From
who?

Any notion of how much it might cost to have a machine shop take a
larger angle and whack it down? These need machining anyway: they have
to be cut to length, then drilled on both webs and tapped on one -- so
it would be a case of "while it's in the machine anyway, make one or
two additional cuts". Precision is nearly nonexistent: +/- 0.05" would
be fine, and finish wouldn't be a huge issue: as long as the edges are
deburred and the cut side isn't so rough that it draws blood when
handled things would be fine; I would expect that a decent shop with
even a minimal sense of pride would insist on a much better finish than
necessary to get the job done.


"Structural" is generally 6061 and it has an inside fillet whereas
"architectural" is generally 6063 and has sharp corner.

That said, your problem probably isn't going to be finding it with sharp
corners, rather, it's going to be finding it in your desired (1/4) in
wall thickness.

Suggest try this link you just might just find something...

http://tinyurl.com/6vwjdzj

I should re-do my thermal analysis. (I.e., something more thorough than
"use what's already there"). 1/8" may be thick enough.

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

"Tim Wescott" wrote in message ...
On Wed, 21 Mar 2012 15:28:34 -0700, PrecisionmachinisT wrote:

"Tim Wescott" wrote in message
...
So, for my day job I'm working on a circuit board design to replace
something which features a heatsink made from aluminum angle. It's 1"
x 1" x 1/4", with nice square corners everywhere (radius 0.02").

Up to now I've been blithely assuming that this is an off-the-shelf
item that I can get anywhere -- but it looks like it may be harder to
get than that. Worse, I'd really like to extend the heat sink another
1/2" or even 1" under the board, while keeping the outside leg at 1".

So I want to specify something that won't have their mechanical
engineers muttering under their breath _too_ much about @#$% EEs with
time on their hands...

McMaster carries aluminum angle, but it describes the inside corner and
the inside ends of the legs as "rounded", without saying what the
radius is. I can handle a radius on the inside corner, but that radius
on the leg takes away from area that I want touching my board.
Furthermore, McMaster only carries angle with even-length sides.

So my questions a

Is there any commonly-available aluminum angle that has corners that
one wouldn't describe as "rounded"? From who?

If I must go with rounded corners, can I expect that there is a
standard? What is it? Is there a place I might find it on the web?
(Machinery's Handbook doesn't seem to list anything like that).

Is there any commonly-available aluminum angle with uneven leg lengths?
I'm specifically looking for 1" x 1.5" x 1/4", or 1" x 2" x 1/4". From
who?

Any notion of how much it might cost to have a machine shop take a
larger angle and whack it down? These need machining anyway: they have
to be cut to length, then drilled on both webs and tapped on one -- so
it would be a case of "while it's in the machine anyway, make one or
two additional cuts". Precision is nearly nonexistent: +/- 0.05" would
be fine, and finish wouldn't be a huge issue: as long as the edges are
deburred and the cut side isn't so rough that it draws blood when
handled things would be fine; I would expect that a decent shop with
even a minimal sense of pride would insist on a much better finish than
necessary to get the job done.


"Structural" is generally 6061 and it has an inside fillet whereas
"architectural" is generally 6063 and has sharp corner.

That said, your problem probably isn't going to be finding it with sharp
corners, rather, it's going to be finding it in your desired (1/4) in
wall thickness.

Suggest try this link you just might just find something...

http://tinyurl.com/6vwjdzj

I should re-do my thermal analysis. (I.e., something more thorough than
"use what's already there"). 1/8" may be thick enough.


Additional mass does not increase thermal radiation capacity, it only increases the amount of TIME that it takes for the unit reach thermal equilibrium--which is only appropriate for something that has a rigid duty cycle...otherwise you're only asking for trouble.

If you want to INCREASE BTUH CAPACITY, then either increase airflow or increase the total amount of surface area by milling grooves or by adding fins.

On Wed, 21 Mar 2012 15:59:46 -0700, PrecisionmachinisT wrote:

"Tim Wescott" wrote in message
...
On Wed, 21 Mar 2012 15:28:34 -0700, PrecisionmachinisT wrote:

"Tim Wescott" wrote in message
...
So, for my day job I'm working on a circuit board design to replace
something which features a heatsink made from aluminum angle. It's
1" x 1" x 1/4", with nice square corners everywhere (radius 0.02").

Up to now I've been blithely assuming that this is an off-the-shelf
item that I can get anywhere -- but it looks like it may be harder to
get than that. Worse, I'd really like to extend the heat sink
another 1/2" or even 1" under the board, while keeping the outside
leg at 1".

So I want to specify something that won't have their mechanical
engineers muttering under their breath _too_ much about @#$% EEs with
time on their hands...

McMaster carries aluminum angle, but it describes the inside corner
and the inside ends of the legs as "rounded", without saying what the
radius is. I can handle a radius on the inside corner, but that
radius on the leg takes away from area that I want touching my board.
Furthermore, McMaster only carries angle with even-length sides.

So my questions a

Is there any commonly-available aluminum angle that has corners that
one wouldn't describe as "rounded"? From who?

If I must go with rounded corners, can I expect that there is a
standard? What is it? Is there a place I might find it on the web?
(Machinery's Handbook doesn't seem to list anything like that).

Is there any commonly-available aluminum angle with uneven leg
lengths? I'm specifically looking for 1" x 1.5" x 1/4", or 1" x 2" x
1/4". From who?

Any notion of how much it might cost to have a machine shop take a
larger angle and whack it down? These need machining anyway: they
have to be cut to length, then drilled on both webs and tapped on one
-- so it would be a case of "while it's in the machine anyway, make
one or two additional cuts". Precision is nearly nonexistent: +/-
0.05" would be fine, and finish wouldn't be a huge issue: as long as
the edges are deburred and the cut side isn't so rough that it draws
blood when handled things would be fine; I would expect that a decent
shop with even a minimal sense of pride would insist on a much better
finish than necessary to get the job done.


"Structural" is generally 6061 and it has an inside fillet whereas
"architectural" is generally 6063 and has sharp corner.

That said, your problem probably isn't going to be finding it with
sharp corners, rather, it's going to be finding it in your desired
(1/4) in wall thickness.

Suggest try this link you just might just find something...

http://tinyurl.com/6vwjdzj

I should re-do my thermal analysis. (I.e., something more thorough
than "use what's already there"). 1/8" may be thick enough.


Additional mass does not increase thermal radiation capacity, it only
increases the amount of TIME that it takes for the unit reach thermal
equilibrium--which is only appropriate for something that has a rigid
duty cycle...otherwise you're only asking for trouble.

If you want to INCREASE BTUH CAPACITY, then either increase airflow or
increase the total amount of surface area by milling grooves or by
adding fins.

In this case the mount/heatsink's job is to carry heat from the board to
the frame of the machine. Extra thickness would, indeed, carry that heat
from the board to the mounting flange more effectively -- but I don't
think that is the worst offender in the temperature-drop sweepstakes.

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

On Mar 21, 7:06*pm, Tim Wescott wrote:
On Wed, 21 Mar 2012 15:59:46 -0700, PrecisionmachinisT wrote:
"Tim Wescott" wrote in message
...
On Wed, 21 Mar 2012 15:28:34 -0700, PrecisionmachinisT wrote:

"Tim Wescott" wrote in message
...
So, for my day job I'm working on a circuit board design to replace
something which features a heatsink made from aluminum angle. *It's
1" x 1" x 1/4", with nice square corners everywhere (radius 0.02")..

Up to now I've been blithely assuming that this is an off-the-shelf
item that I can get anywhere -- but it looks like it may be harder to
get than that. *Worse, I'd really like to extend the heat sink
another 1/2" or even 1" under the board, while keeping the outside
leg at 1".

So I want to specify something that won't have their mechanical
engineers muttering under their breath _too_ much about @#$% EEs with
time on their hands...

McMaster carries aluminum angle, but it describes the inside corner
and the inside ends of the legs as "rounded", without saying what the
radius is. *I can handle a radius on the inside corner, but that
radius on the leg takes away from area that I want touching my board..
Furthermore, McMaster only carries angle with even-length sides.

So my questions a

Is there any commonly-available aluminum angle that has corners that
one wouldn't describe as "rounded"? *From who?

If I must go with rounded corners, can I expect that there is a
standard? *What is it? *Is there a place I might find it on the web?
(Machinery's Handbook doesn't seem to list anything like that).

Is there any commonly-available aluminum angle with uneven leg
lengths? I'm specifically looking for 1" x 1.5" x 1/4", or 1" x 2" x
1/4". *From who?

Any notion of how much it might cost to have a machine shop take a
larger angle and whack it down? *These need machining anyway: they
have to be cut to length, then drilled on both webs and tapped on one
-- so it would be a case of "while it's in the machine anyway, make
one or two additional cuts". *Precision is nearly nonexistent: +/-
0.05" would be fine, and finish wouldn't be a huge issue: as long as
the edges are deburred and the cut side isn't so rough that it draws
blood when handled things would be fine; I would expect that a decent
shop with even a minimal sense of pride would insist on a much better
finish than necessary to get the job done.

"Structural" is generally 6061 and it has an inside fillet whereas
"architectural" is generally 6063 and has sharp corner.

That said, your problem probably isn't going to be finding it with
sharp corners, rather, it's going to be finding it in your desired
(1/4) in wall thickness.

Suggest try this link you just might just find something...

http://tinyurl.com/6vwjdzj

I should re-do my thermal analysis. *(I.e., something more thorough
than "use what's already there"). *1/8" may be thick enough.

Additional mass does not increase thermal radiation capacity, it only
increases the amount of TIME that it takes for the unit reach thermal
equilibrium--which is only appropriate for something that has a rigid
duty cycle...otherwise you're only asking for trouble.

If you want to INCREASE BTUH CAPACITY, then either increase airflow or
increase the total amount of surface area by milling grooves or by
adding fins.

In this case the mount/heatsink's job is to carry heat from the board to
the frame of the machine. *Extra thickness would, indeed, carry that heat
from the board to the mounting flange more effectively -- but I don't
think that is the worst offender in the temperature-drop sweepstakes.

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Softwarehttp://www.wescottdesign.com

Does the heat sink have fins? you did not seem to mention fins in the
OP. When I had to custom make heat sinks I got a bunch of roughly
matching ones (1x1 seems like a popular size) and shaved them down to
my desired size with a grinding mill (using a regular mill bends the
fins all over the place). heat sinks usually have square corners.
Digikey as you probably know has all sorts of heat sinks. I got my
batch off ebay for dirt cheap, probably from a hi tech company
liquidation.

On Wed, 21 Mar 2012 12:21:57 -0500, Tim Wescott
wrote:

So, for my day job I'm working on a circuit board design to replace
something which features a heatsink made from aluminum angle. It's 1" x
1" x 1/4", with nice square corners everywhere (radius 0.02").

Up to now I've been blithely assuming that this is an off-the-shelf item
that I can get anywhere -- but it looks like it may be harder to get than
that. Worse, I'd really like to extend the heat sink another 1/2" or
even 1" under the board, while keeping the outside leg at 1".

So I want to specify something that won't have their mechanical engineers
muttering under their breath _too_ much about @#$% EEs with time on their
hands...

McMaster carries aluminum angle, but it describes the inside corner and
the inside ends of the legs as "rounded", without saying what the radius
is. I can handle a radius on the inside corner, but that radius on the
leg takes away from area that I want touching my board. Furthermore,
McMaster only carries angle with even-length sides.

So my questions a

Is there any commonly-available aluminum angle that has corners that one
wouldn't describe as "rounded"? From who?

If I must go with rounded corners, can I expect that there is a
standard? What is it? Is there a place I might find it on the web?
(Machinery's Handbook doesn't seem to list anything like that).

Is there any commonly-available aluminum angle with uneven leg lengths?
I'm specifically looking for 1" x 1.5" x 1/4", or 1" x 2" x 1/4". From
who?

Any notion of how much it might cost to have a machine shop take a larger
angle and whack it down? These need machining anyway: they have to be
cut to length, then drilled on both webs and tapped on one -- so it would
be a case of "while it's in the machine anyway, make one or two
additional cuts". Precision is nearly nonexistent: +/- 0.05" would be
fine, and finish wouldn't be a huge issue: as long as the edges are
deburred and the cut side isn't so rough that it draws blood when handled
things would be fine; I would expect that a decent shop with even a
minimal sense of pride would insist on a much better finish than
necessary to get the job done.
When I've needed sharp cornered aluminum angle in the past I've
ordered "architectural" angle. It looks like you may need to order 2x2
in order to get the 1/4 thickness. And the alloy is 6063T52. If I was
cutting the angle shorter I would probably use a 3" dia. slotting saw
blade in the mill and spin it really fast. That would leave a good
finish, be accurate, and be fast.
Eric

wrote in message ...
On Wed, 21 Mar 2012 12:21:57 -0500, Tim Wescott
wrote:

So, for my day job I'm working on a circuit board design to replace
something which features a heatsink made from aluminum angle. It's 1" x
1" x 1/4", with nice square corners everywhere (radius 0.02").

Up to now I've been blithely assuming that this is an off-the-shelf item
that I can get anywhere -- but it looks like it may be harder to get than
that. Worse, I'd really like to extend the heat sink another 1/2" or
even 1" under the board, while keeping the outside leg at 1".

So I want to specify something that won't have their mechanical engineers
muttering under their breath _too_ much about @#$% EEs with time on their
hands...

McMaster carries aluminum angle, but it describes the inside corner and
the inside ends of the legs as "rounded", without saying what the radius
is. I can handle a radius on the inside corner, but that radius on the
leg takes away from area that I want touching my board. Furthermore,
McMaster only carries angle with even-length sides.

So my questions a

Is there any commonly-available aluminum angle that has corners that one
wouldn't describe as "rounded"? From who?

If I must go with rounded corners, can I expect that there is a
standard? What is it? Is there a place I might find it on the web?
(Machinery's Handbook doesn't seem to list anything like that).

Is there any commonly-available aluminum angle with uneven leg lengths?
I'm specifically looking for 1" x 1.5" x 1/4", or 1" x 2" x 1/4". From
who?

Any notion of how much it might cost to have a machine shop take a larger
angle and whack it down? These need machining anyway: they have to be
cut to length, then drilled on both webs and tapped on one -- so it would
be a case of "while it's in the machine anyway, make one or two
additional cuts". Precision is nearly nonexistent: +/- 0.05" would be
fine, and finish wouldn't be a huge issue: as long as the edges are
deburred and the cut side isn't so rough that it draws blood when handled
things would be fine; I would expect that a decent shop with even a
minimal sense of pride would insist on a much better finish than
necessary to get the job done.
When I've needed sharp cornered aluminum angle in the past I've
ordered "architectural" angle. It looks like you may need to order 2x2
in order to get the 1/4 thickness. And the alloy is 6063T52. If I was
cutting the angle shorter I would probably use a 3" dia. slotting saw
blade in the mill and spin it really fast. That would leave a good
finish, be accurate, and be fast.
Eric

For low /medium quantity volume production it may be cheaper in the long run to just buy 1x1 square stock--cut away excess, drill / tap....flip over, drill / tap / partoff into individual pieces.

On Wed, 21 Mar 2012 18:39:02 -0700, "PrecisionmachinisT"
wrote:


wrote in message ...
On Wed, 21 Mar 2012 12:21:57 -0500, Tim Wescott
wrote:

So, for my day job I'm working on a circuit board design to replace
something which features a heatsink made from aluminum angle. It's 1" x
1" x 1/4", with nice square corners everywhere (radius 0.02").

Up to now I've been blithely assuming that this is an off-the-shelf item
that I can get anywhere -- but it looks like it may be harder to get than
that. Worse, I'd really like to extend the heat sink another 1/2" or
even 1" under the board, while keeping the outside leg at 1".

So I want to specify something that won't have their mechanical engineers
muttering under their breath _too_ much about @#$% EEs with time on their
hands...

McMaster carries aluminum angle, but it describes the inside corner and
the inside ends of the legs as "rounded", without saying what the radius
is. I can handle a radius on the inside corner, but that radius on the
leg takes away from area that I want touching my board. Furthermore,
McMaster only carries angle with even-length sides.

So my questions a

Is there any commonly-available aluminum angle that has corners that one
wouldn't describe as "rounded"? From who?

If I must go with rounded corners, can I expect that there is a
standard? What is it? Is there a place I might find it on the web?
(Machinery's Handbook doesn't seem to list anything like that).

Is there any commonly-available aluminum angle with uneven leg lengths?
I'm specifically looking for 1" x 1.5" x 1/4", or 1" x 2" x 1/4". From
who?

Any notion of how much it might cost to have a machine shop take a larger
angle and whack it down? These need machining anyway: they have to be
cut to length, then drilled on both webs and tapped on one -- so it would
be a case of "while it's in the machine anyway, make one or two
additional cuts". Precision is nearly nonexistent: +/- 0.05" would be
fine, and finish wouldn't be a huge issue: as long as the edges are
deburred and the cut side isn't so rough that it draws blood when handled
things would be fine; I would expect that a decent shop with even a
minimal sense of pride would insist on a much better finish than
necessary to get the job done.
When I've needed sharp cornered aluminum angle in the past I've
ordered "architectural" angle. It looks like you may need to order 2x2
in order to get the 1/4 thickness. And the alloy is 6063T52. If I was
cutting the angle shorter I would probably use a 3" dia. slotting saw
blade in the mill and spin it really fast. That would leave a good
finish, be accurate, and be fast.
Eric

For low /medium quantity volume production it may be cheaper in the long run to just buy 1x1 square stock--cut away excess, drill / tap....flip over, drill / tap / partoff into individual pieces.
He's looking for 1.5 x 1 x 1/4. If the parts aren't much more than 6
inches long then rectangular stock could be turned into angle as you
suggest. And it would be fast. Modern carbide cutters for aluminum
remove material in a hurry.
Eric

On Wed, 21 Mar 2012 12:21:57 -0500, Tim Wescott
wrote:

So, for my day job I'm working on a circuit board design to replace
something which features a heatsink made from aluminum angle. It's 1" x
1" x 1/4", with nice square corners everywhere (radius 0.02").

Up to now I've been blithely assuming that this is an off-the-shelf item
that I can get anywhere -- but it looks like it may be harder to get than
that. Worse, I'd really like to extend the heat sink another 1/2" or
even 1" under the board, while keeping the outside leg at 1".

So I want to specify something that won't have their mechanical engineers
muttering under their breath _too_ much about @#$% EEs with time on their
hands...

McMaster carries aluminum angle, but it describes the inside corner and
the inside ends of the legs as "rounded", without saying what the radius
is. I can handle a radius on the inside corner, but that radius on the
leg takes away from area that I want touching my board. Furthermore,
McMaster only carries angle with even-length sides.

So my questions a

Is there any commonly-available aluminum angle that has corners that one
wouldn't describe as "rounded"? From who?

If I must go with rounded corners, can I expect that there is a
standard? What is it? Is there a place I might find it on the web?
(Machinery's Handbook doesn't seem to list anything like that).

Is there any commonly-available aluminum angle with uneven leg lengths?
I'm specifically looking for 1" x 1.5" x 1/4", or 1" x 2" x 1/4". From
who?

Any notion of how much it might cost to have a machine shop take a larger
angle and whack it down? These need machining anyway: they have to be
cut to length, then drilled on both webs and tapped on one -- so it would
be a case of "while it's in the machine anyway, make one or two
additional cuts". Precision is nearly nonexistent: +/- 0.05" would be
fine, and finish wouldn't be a huge issue: as long as the edges are
deburred and the cut side isn't so rough that it draws blood when handled
things would be fine; I would expect that a decent shop with even a
minimal sense of pride would insist on a much better finish than
necessary to get the job done.


Try http://www.onlinemetals.com/merchant...p=2&top_cat=60

--
Cheers,

John B.

On Wed, 21 Mar 2012 17:57:10 -0700, runcyclexcski wrote:

On Mar 21, 7:06Â*pm, Tim Wescott wrote:
On Wed, 21 Mar 2012 15:59:46 -0700, PrecisionmachinisT wrote:
"Tim Wescott" wrote in message
...
On Wed, 21 Mar 2012 15:28:34 -0700, PrecisionmachinisT wrote:

"Tim Wescott" wrote in message
...
So, for my day job I'm working on a circuit board design to
replace something which features a heatsink made from aluminum
angle. Â*It's 1" x 1" x 1/4", with nice square corners everywhere
(radius 0.02").

Up to now I've been blithely assuming that this is an
off-the-shelf item that I can get anywhere -- but it looks like it
may be harder to get than that. Â*Worse, I'd really like to extend
the heat sink another 1/2" or even 1" under the board, while
keeping the outside leg at 1".

So I want to specify something that won't have their mechanical
engineers muttering under their breath _too_ much about @#$% EEs
with time on their hands...

McMaster carries aluminum angle, but it describes the inside
corner and the inside ends of the legs as "rounded", without
saying what the radius is. Â*I can handle a radius on the inside
corner, but that radius on the leg takes away from area that I
want touching my board. Furthermore, McMaster only carries angle
with even-length sides.

So my questions a

Is there any commonly-available aluminum angle that has corners
that one wouldn't describe as "rounded"? Â*From who?

If I must go with rounded corners, can I expect that there is a
standard? Â*What is it? Â*Is there a place I might find it on the
web? (Machinery's Handbook doesn't seem to list anything like
that).

Is there any commonly-available aluminum angle with uneven leg
lengths? I'm specifically looking for 1" x 1.5" x 1/4", or 1" x 2"
x 1/4". Â*From who?

Any notion of how much it might cost to have a machine shop take a
larger angle and whack it down? Â*These need machining anyway: they
have to be cut to length, then drilled on both webs and tapped on
one -- so it would be a case of "while it's in the machine anyway,
make one or two additional cuts". Â*Precision is nearly
nonexistent: +/- 0.05" would be fine, and finish wouldn't be a
huge issue: as long as the edges are deburred and the cut side
isn't so rough that it draws blood when handled things would be
fine; I would expect that a decent shop with even a minimal sense
of pride would insist on a much better finish than necessary to
get the job done.

"Structural" is generally 6061 and it has an inside fillet whereas
"architectural" is generally 6063 and has sharp corner.

That said, your problem probably isn't going to be finding it with
sharp corners, rather, it's going to be finding it in your desired
(1/4) in wall thickness.

Suggest try this link you just might just find something...

http://tinyurl.com/6vwjdzj

I should re-do my thermal analysis. Â*(I.e., something more thorough
than "use what's already there"). Â*1/8" may be thick enough.

Additional mass does not increase thermal radiation capacity, it only
increases the amount of TIME that it takes for the unit reach thermal
equilibrium--which is only appropriate for something that has a rigid
duty cycle...otherwise you're only asking for trouble.

If you want to INCREASE BTUH CAPACITY, then either increase airflow
or increase the total amount of surface area by milling grooves or by
adding fins.

In this case the mount/heatsink's job is to carry heat from the board
to the frame of the machine. Â*Extra thickness would, indeed, carry that
heat from the board to the mounting flange more effectively -- but I
don't think that is the worst offender in the temperature-drop
sweepstakes.

--
My liberal friends think I'm a conservative kook. My conservative
friends think I'm a liberal kook. Why am I not happy that they have
found common ground?

Tim Wescott, Communications, Control, Circuits &
Softwarehttp://www.wescottdesign.com

Does the heat sink have fins? you did not seem to mention fins in the
OP. When I had to custom make heat sinks I got a bunch of roughly
matching ones (1x1 seems like a popular size) and shaved them down to my
desired size with a grinding mill (using a regular mill bends the fins
all over the place). heat sinks usually have square corners. Digikey as
you probably know has all sorts of heat sinks. I got my batch off ebay
for dirt cheap, probably from a hi tech company liquidation.

No fins. It's really a "heat conductor", or perhaps just a thick bracket
that conveys heat. I don't know what you might call it -- but it's not a
device to better match the thermal impedance of a solid with the thermal
impedance of the air.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

wrote in message
news
On Wed, 21 Mar 2012 18:39:02 -0700, "PrecisionmachinisT"
wrote:


wrote in message
. ..
On Wed, 21 Mar 2012 12:21:57 -0500, Tim Wescott
wrote:

So, for my day job I'm working on a circuit board design to replace
something which features a heatsink made from aluminum angle. It's 1" x
1" x 1/4", with nice square corners everywhere (radius 0.02").

Up to now I've been blithely assuming that this is an off-the-shelf item
that I can get anywhere -- but it looks like it may be harder to get
than
that. Worse, I'd really like to extend the heat sink another 1/2" or
even 1" under the board, while keeping the outside leg at 1".

So I want to specify something that won't have their mechanical
engineers
muttering under their breath _too_ much about @#$% EEs with time on
their
hands...

McMaster carries aluminum angle, but it describes the inside corner and
the inside ends of the legs as "rounded", without saying what the radius
is. I can handle a radius on the inside corner, but that radius on the
leg takes away from area that I want touching my board. Furthermore,
McMaster only carries angle with even-length sides.

So my questions a

Is there any commonly-available aluminum angle that has corners that one
wouldn't describe as "rounded"? From who?

If I must go with rounded corners, can I expect that there is a
standard? What is it? Is there a place I might find it on the web?
(Machinery's Handbook doesn't seem to list anything like that).

Is there any commonly-available aluminum angle with uneven leg lengths?
I'm specifically looking for 1" x 1.5" x 1/4", or 1" x 2" x 1/4". From
who?

Any notion of how much it might cost to have a machine shop take a
larger
angle and whack it down? These need machining anyway: they have to be
cut to length, then drilled on both webs and tapped on one -- so it
would
be a case of "while it's in the machine anyway, make one or two
additional cuts". Precision is nearly nonexistent: +/- 0.05" would be
fine, and finish wouldn't be a huge issue: as long as the edges are
deburred and the cut side isn't so rough that it draws blood when
handled
things would be fine; I would expect that a decent shop with even a
minimal sense of pride would insist on a much better finish than
necessary to get the job done.
When I've needed sharp cornered aluminum angle in the past I've
ordered "architectural" angle. It looks like you may need to order 2x2
in order to get the 1/4 thickness. And the alloy is 6063T52. If I was
cutting the angle shorter I would probably use a 3" dia. slotting saw
blade in the mill and spin it really fast. That would leave a good
finish, be accurate, and be fast.
Eric

For low /medium quantity volume production it may be cheaper in the long
run to just buy 1x1 square stock--cut away excess, drill / tap....flip
over, drill / tap / partoff into individual pieces.
He's looking for 1.5 x 1 x 1/4. If the parts aren't much more than 6
inches long then rectangular stock could be turned into angle as you
suggest. And it would be fast. Modern carbide cutters for aluminum
remove material in a hurry.


Agreed but 1.5 x 1 adds quite a bit more waste into the equation...

--for some reason, I had 1x1 stuck in my head...

"Tim Wescott" wrote in message
...
On Wed, 21 Mar 2012 17:57:10 -0700, runcyclexcski wrote:

On Mar 21, 7:06 pm, Tim Wescott wrote:
On Wed, 21 Mar 2012 15:59:46 -0700, PrecisionmachinisT wrote:
"Tim Wescott" wrote in message
...
On Wed, 21 Mar 2012 15:28:34 -0700, PrecisionmachinisT wrote:

"Tim Wescott" wrote in message
...
So, for my day job I'm working on a circuit board design to
replace something which features a heatsink made from aluminum
angle. It's 1" x 1" x 1/4", with nice square corners everywhere
(radius 0.02").

Up to now I've been blithely assuming that this is an
off-the-shelf item that I can get anywhere -- but it looks like it
may be harder to get than that. Worse, I'd really like to extend
the heat sink another 1/2" or even 1" under the board, while
keeping the outside leg at 1".

So I want to specify something that won't have their mechanical
engineers muttering under their breath _too_ much about @#$% EEs
with time on their hands...

McMaster carries aluminum angle, but it describes the inside
corner and the inside ends of the legs as "rounded", without
saying what the radius is. I can handle a radius on the inside
corner, but that radius on the leg takes away from area that I
want touching my board. Furthermore, McMaster only carries angle
with even-length sides.

So my questions a

Is there any commonly-available aluminum angle that has corners
that one wouldn't describe as "rounded"? From who?

If I must go with rounded corners, can I expect that there is a
standard? What is it? Is there a place I might find it on the
web? (Machinery's Handbook doesn't seem to list anything like
that).

Is there any commonly-available aluminum angle with uneven leg
lengths? I'm specifically looking for 1" x 1.5" x 1/4", or 1" x 2"
x 1/4". From who?

Any notion of how much it might cost to have a machine shop take a
larger angle and whack it down? These need machining anyway: they
have to be cut to length, then drilled on both webs and tapped on
one -- so it would be a case of "while it's in the machine anyway,
make one or two additional cuts". Precision is nearly
nonexistent: +/- 0.05" would be fine, and finish wouldn't be a
huge issue: as long as the edges are deburred and the cut side
isn't so rough that it draws blood when handled things would be
fine; I would expect that a decent shop with even a minimal sense
of pride would insist on a much better finish than necessary to
get the job done.

"Structural" is generally 6061 and it has an inside fillet whereas
"architectural" is generally 6063 and has sharp corner.

That said, your problem probably isn't going to be finding it with
sharp corners, rather, it's going to be finding it in your desired
(1/4) in wall thickness.

Suggest try this link you just might just find something...

http://tinyurl.com/6vwjdzj

I should re-do my thermal analysis. (I.e., something more thorough
than "use what's already there"). 1/8" may be thick enough.

Additional mass does not increase thermal radiation capacity, it only
increases the amount of TIME that it takes for the unit reach thermal
equilibrium--which is only appropriate for something that has a rigid
duty cycle...otherwise you're only asking for trouble.

If you want to INCREASE BTUH CAPACITY, then either increase airflow
or increase the total amount of surface area by milling grooves or by
adding fins.

In this case the mount/heatsink's job is to carry heat from the board
to the frame of the machine. Extra thickness would, indeed, carry that
heat from the board to the mounting flange more effectively -- but I
don't think that is the worst offender in the temperature-drop
sweepstakes.

--
My liberal friends think I'm a conservative kook. My conservative
friends think I'm a liberal kook. Why am I not happy that they have
found common ground?

Tim Wescott, Communications, Control, Circuits &
Softwarehttp://www.wescottdesign.com

Does the heat sink have fins? you did not seem to mention fins in the
OP. When I had to custom make heat sinks I got a bunch of roughly
matching ones (1x1 seems like a popular size) and shaved them down to my
desired size with a grinding mill (using a regular mill bends the fins
all over the place). heat sinks usually have square corners. Digikey as
you probably know has all sorts of heat sinks. I got my batch off ebay
for dirt cheap, probably from a hi tech company liquidation.

No fins. It's really a "heat conductor", or perhaps just a thick bracket
that conveys heat. I don't know what you might call it -- but it's not a
device to better match the thermal impedance of a solid with the thermal
impedance of the air.


"heat spreader" is the engineering name I've seen occasionally applied to
parts having that function...

I'm too busy to dink around with new projects for the foreseeable future but
you might want to ask Eric for a ballpark quote...simply make from a solid
bar...

On Mar 21, 9:07*pm, wrote:


When I've needed sharp cornered aluminum angle in the past I've
ordered "architectural" angle. It looks like you may need to order 2x2
in order to get the 1/4 thickness. And the alloy is 6063T52. If I was
cutting the angle shorter I would probably use a 3" dia. *slotting saw
blade in the mill and spin it really fast. That would leave a good
finish, be accurate, and be fast.
Eric

Before deciding on the size, it would be worthwhile to consider the
alloy. I may not remember correctly, but I think 1100 would be
cheaper and also conduct heat much better. So it might be cheaper and
better to use angle with a rounded edge.

Dan

On Thu, 22 Mar 2012 04:29:43 -0700 (PDT), "
wrote:

On Mar 21, 9:07*pm, wrote:


When I've needed sharp cornered aluminum angle in the past I've
ordered "architectural" angle. It looks like you may need to order 2x2
in order to get the 1/4 thickness. And the alloy is 6063T52. If I was
cutting the angle shorter I would probably use a 3" dia. *slotting saw
blade in the mill and spin it really fast. That would leave a good
finish, be accurate, and be fast.
Eric

Before deciding on the size, it would be worthwhile to consider the
alloy. I may not remember correctly, but I think 1100 would be
cheaper and also conduct heat much better. So it might be cheaper and
better to use angle with a rounded edge.

Dan
But machining 1100 is more expensive than 6061 or 6063 because it's so
soft.
Eric

wrote in message
...
On Thu, 22 Mar 2012 04:29:43 -0700 (PDT), "
wrote:

On Mar 21, 9:07 pm, wrote:


When I've needed sharp cornered aluminum angle in the past I've
ordered "architectural" angle. It looks like you may need to order 2x2
in order to get the 1/4 thickness. And the alloy is 6063T52. If I was
cutting the angle shorter I would probably use a 3" dia. slotting saw
blade in the mill and spin it really fast. That would leave a good
finish, be accurate, and be fast.
Eric

Before deciding on the size, it would be worthwhile to consider the
alloy. I may not remember correctly, but I think 1100 would be
cheaper and also conduct heat much better. So it might be cheaper and
better to use angle with a rounded edge.

Dan
But machining 1100 is more expensive than 6061 or 6063 because it's so
soft.
Eric

Pretty sure 1100 isn't supplied in extruded shapes excepting for square,
round and rectangular.

On Thu, 22 Mar 2012 07:39:06 -0700, "PrecisionmachinisT"
wrote:


wrote in message
.. .
On Thu, 22 Mar 2012 04:29:43 -0700 (PDT), "
wrote:

On Mar 21, 9:07 pm, wrote:


When I've needed sharp cornered aluminum angle in the past I've
ordered "architectural" angle. It looks like you may need to order 2x2
in order to get the 1/4 thickness. And the alloy is 6063T52. If I was
cutting the angle shorter I would probably use a 3" dia. slotting saw
blade in the mill and spin it really fast. That would leave a good
finish, be accurate, and be fast.
Eric

Before deciding on the size, it would be worthwhile to consider the
alloy. I may not remember correctly, but I think 1100 would be
cheaper and also conduct heat much better. So it might be cheaper and
better to use angle with a rounded edge.

Dan
But machining 1100 is more expensive than 6061 or 6063 because it's so
soft.
Eric

Pretty sure 1100 isn't supplied in extruded shapes excepting for square,
round and rectangular.

You mentioned 6063. That's the standard extrustion alloy for heat
sinks. Conductivity is around 200 W/m-K in low tempers. For
comparison, 1199-O or 1100 is in the neighborhood of 240.

Extrusion dies are so cheap to make these days that extrusion jobbers
often accumulate large numbers of them, and offer standard extruded
shapes, including simple angles and elaborate finned heat sinks, as
off-the-shelf stock items. If you need a lot, you can get quite short
runs on a jobbing basis.

Then you just bandsaw them to length. That's standard practice.

The reason dies are so cheap to make is that they're easy wirecut EDM
work. They cut the die shape and the taper in one pass.

--
Ed Huntress

On Wed, 21 Mar 2012 22:10:34 -0700, PrecisionmachinisT wrote:

"Tim Wescott" wrote in message
...
On Wed, 21 Mar 2012 17:57:10 -0700, runcyclexcski wrote:

On Mar 21, 7:06 pm, Tim Wescott wrote:
On Wed, 21 Mar 2012 15:59:46 -0700, PrecisionmachinisT wrote:
"Tim Wescott" wrote in message
...
On Wed, 21 Mar 2012 15:28:34 -0700, PrecisionmachinisT wrote:

"Tim Wescott" wrote in message
...
So, for my day job I'm working on a circuit board design to
replace something which features a heatsink made from aluminum
angle. It's 1" x 1" x 1/4", with nice square corners everywhere
(radius 0.02").

Up to now I've been blithely assuming that this is an
off-the-shelf item that I can get anywhere -- but it looks like
it may be harder to get than that. Worse, I'd really like to
extend the heat sink another 1/2" or even 1" under the board,
while keeping the outside leg at 1".

So I want to specify something that won't have their mechanical
engineers muttering under their breath _too_ much about @#$% EEs
with time on their hands...

McMaster carries aluminum angle, but it describes the inside
corner and the inside ends of the legs as "rounded", without
saying what the radius is. I can handle a radius on the inside
corner, but that radius on the leg takes away from area that I
want touching my board. Furthermore, McMaster only carries angle
with even-length sides.

So my questions a

Is there any commonly-available aluminum angle that has corners
that one wouldn't describe as "rounded"? From who?

If I must go with rounded corners, can I expect that there is a
standard? What is it? Is there a place I might find it on the
web? (Machinery's Handbook doesn't seem to list anything like
that).

Is there any commonly-available aluminum angle with uneven leg
lengths? I'm specifically looking for 1" x 1.5" x 1/4", or 1" x
2" x 1/4". From who?

Any notion of how much it might cost to have a machine shop take
a larger angle and whack it down? These need machining anyway:
they have to be cut to length, then drilled on both webs and
tapped on one -- so it would be a case of "while it's in the
machine anyway, make one or two additional cuts". Precision is
nearly nonexistent: +/- 0.05" would be fine, and finish wouldn't
be a huge issue: as long as the edges are deburred and the cut
side isn't so rough that it draws blood when handled things
would be fine; I would expect that a decent shop with even a
minimal sense of pride would insist on a much better finish than
necessary to get the job done.

"Structural" is generally 6061 and it has an inside fillet
whereas "architectural" is generally 6063 and has sharp corner.

That said, your problem probably isn't going to be finding it
with sharp corners, rather, it's going to be finding it in your
desired (1/4) in wall thickness.

Suggest try this link you just might just find something...

http://tinyurl.com/6vwjdzj

I should re-do my thermal analysis. (I.e., something more thorough
than "use what's already there"). 1/8" may be thick enough.

Additional mass does not increase thermal radiation capacity, it
only increases the amount of TIME that it takes for the unit reach
thermal equilibrium--which is only appropriate for something that
has a rigid duty cycle...otherwise you're only asking for trouble.

If you want to INCREASE BTUH CAPACITY, then either increase airflow
or increase the total amount of surface area by milling grooves or
by adding fins.

In this case the mount/heatsink's job is to carry heat from the board
to the frame of the machine. Extra thickness would, indeed, carry
that heat from the board to the mounting flange more effectively --
but I don't think that is the worst offender in the temperature-drop
sweepstakes.

--
My liberal friends think I'm a conservative kook. My conservative
friends think I'm a liberal kook. Why am I not happy that they have
found common ground?

Tim Wescott, Communications, Control, Circuits &
Softwarehttp://www.wescottdesign.com

Does the heat sink have fins? you did not seem to mention fins in the
OP. When I had to custom make heat sinks I got a bunch of roughly
matching ones (1x1 seems like a popular size) and shaved them down to
my desired size with a grinding mill (using a regular mill bends the
fins all over the place). heat sinks usually have square corners.
Digikey as you probably know has all sorts of heat sinks. I got my
batch off ebay for dirt cheap, probably from a hi tech company
liquidation.

No fins. It's really a "heat conductor", or perhaps just a thick
bracket that conveys heat. I don't know what you might call it -- but
it's not a device to better match the thermal impedance of a solid with
the thermal impedance of the air.


"heat spreader" is the engineering name I've seen occasionally applied
to parts having that function...

I'm too busy to dink around with new projects for the foreseeable future
but you might want to ask Eric for a ballpark quote...simply make from a
solid bar...

Thanks. "Heat spreader" is, indeed a term that I remember now that
you've joggled my memory.

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

"Ed Huntress" wrote in message ...
On Thu, 22 Mar 2012 07:39:06 -0700, "PrecisionmachinisT"
wrote:


wrote in message
. ..
On Thu, 22 Mar 2012 04:29:43 -0700 (PDT), "
wrote:

On Mar 21, 9:07 pm, wrote:


When I've needed sharp cornered aluminum angle in the past I've
ordered "architectural" angle. It looks like you may need to order 2x2
in order to get the 1/4 thickness. And the alloy is 6063T52. If I was
cutting the angle shorter I would probably use a 3" dia. slotting saw
blade in the mill and spin it really fast. That would leave a good
finish, be accurate, and be fast.
Eric

Before deciding on the size, it would be worthwhile to consider the
alloy. I may not remember correctly, but I think 1100 would be
cheaper and also conduct heat much better. So it might be cheaper and
better to use angle with a rounded edge.

Dan
But machining 1100 is more expensive than 6061 or 6063 because it's so
soft.
Eric

Pretty sure 1100 isn't supplied in extruded shapes excepting for square,
round and rectangular.

You mentioned 6063. That's the standard extrustion alloy for heat
sinks. Conductivity is around 200 W/m-K in low tempers. For
comparison, 1199-O or 1100 is in the neighborhood of 240.

Extrusion dies are so cheap to make these days that extrusion jobbers
often accumulate large numbers of them, and offer standard extruded
shapes, including simple angles and elaborate finned heat sinks, as
off-the-shelf stock items. If you need a lot, you can get quite short
runs on a jobbing basis.

Then you just bandsaw them to length. That's standard practice.

The reason dies are so cheap to make is that they're easy wirecut EDM
work. They cut the die shape and the taper in one pass.


Last time I bought custom extrusion pretty sure the minimum run was 2000lbs, but that was at least 10 years ago.

On Thu, 22 Mar 2012 14:00:38 -0700, "PrecisionmachinisT"
wrote:


"Ed Huntress" wrote in message ...
On Thu, 22 Mar 2012 07:39:06 -0700, "PrecisionmachinisT"
wrote:


wrote in message
...
On Thu, 22 Mar 2012 04:29:43 -0700 (PDT), "
wrote:

On Mar 21, 9:07 pm, wrote:


When I've needed sharp cornered aluminum angle in the past I've
ordered "architectural" angle. It looks like you may need to order 2x2
in order to get the 1/4 thickness. And the alloy is 6063T52. If I was
cutting the angle shorter I would probably use a 3" dia. slotting saw
blade in the mill and spin it really fast. That would leave a good
finish, be accurate, and be fast.
Eric

Before deciding on the size, it would be worthwhile to consider the
alloy. I may not remember correctly, but I think 1100 would be
cheaper and also conduct heat much better. So it might be cheaper and
better to use angle with a rounded edge.

Dan
But machining 1100 is more expensive than 6061 or 6063 because it's so
soft.
Eric

Pretty sure 1100 isn't supplied in extruded shapes excepting for square,
round and rectangular.

You mentioned 6063. That's the standard extrustion alloy for heat
sinks. Conductivity is around 200 W/m-K in low tempers. For
comparison, 1199-O or 1100 is in the neighborhood of 240.

Extrusion dies are so cheap to make these days that extrusion jobbers
often accumulate large numbers of them, and offer standard extruded
shapes, including simple angles and elaborate finned heat sinks, as
off-the-shelf stock items. If you need a lot, you can get quite short
runs on a jobbing basis.

Then you just bandsaw them to length. That's standard practice.

The reason dies are so cheap to make is that they're easy wirecut EDM
work. They cut the die shape and the taper in one pass.


Last time I bought custom extrusion pretty sure the minimum run was 2000lbs, but that was at least 10 years ago.

Most of the custom extruders have no minimum, but of course the setup
charge can make really small runs too expensive.

The better deal is to buy one of their stock shapes. I just took a
look and saw that several of them offer sharp-cornered angles with
0.250" thick legs. Leg length seems to be 1.5" or more in that
thickness.

--
Ed Huntress

On Thu, 22 Mar 2012 10:30:26 +0700, John B. wrote:
On Wed, 21 Mar 2012 12:21:57 -0500, Tim Wescott wrote:

So, for my day job I'm working on a circuit board design to replace
something which features a heatsink made from aluminum angle. It's 1" x
1" x 1/4", with nice square corners everywhere (radius 0.02").

[...] I'd really like to extend the heat sink another 1/2"
or even 1" under the board, while keeping the outside leg at 1".
....
McMaster carries aluminum angle, but it describes the inside corner and
the inside ends of the legs as "rounded", without saying what the radius
is. I can handle a radius on the inside corner, but that radius on the
leg takes away from area that I want touching my board. Furthermore,
McMaster only carries angle with even-length sides.
....
Is there any commonly-available aluminum angle with uneven leg lengths?
I'm specifically looking for 1" x 1.5" x 1/4", or 1" x 2" x 1/4". From
who?

Any notion of how much it might cost to have a machine shop take a
larger angle and whack it down? These need machining anyway: they have
to be cut to length, then drilled on both webs and tapped on one -- so
it would be a case of "while it's in the machine anyway, make one or two
additional cuts". Precision is nearly nonexistent: +/- 0.05" would be
fine, and finish wouldn't be a huge issue: as long as the edges are
deburred and the cut side isn't so rough that it draws blood [...]

Try http://www.onlinemetals.com/merchant...p=2&top_cat=60

Another possibility at onlinemetals is channel, eg 3" x 1" x 1/8" as at
http://www.onlinemetals.com/merchant.cfm?pid=9712&step=4&showunits=inches&id=2 97&top_cat=60
so one cut gives two pieces of about 1.5" x 1" x 1/8" angle.
Cost per pound looks similar (for angle and channel) but reduced
waste using channel might lower the cost.

If kerf is 0.1", cutting the 2"x2"x1/4" architectural channel as at
http://www.onlinemetals.com/merchant.cfm?pid=7801&step=4&showunits=inches&id=2 97&top_cat=60
or near middle of http://www.mcmaster.com/#standard-aluminum-u-channels/=gs2bb0
would give 2"x0.95x1/4" pieces.

--
jiw

On Thu, 22 Mar 2012 11:38:15 -0500, Tim Wescott
wrote:

On Wed, 21 Mar 2012 22:10:34 -0700, PrecisionmachinisT wrote:

"Tim Wescott" wrote in message
...
On Wed, 21 Mar 2012 17:57:10 -0700, runcyclexcski wrote:

On Mar 21, 7:06 pm, Tim Wescott wrote:
On Wed, 21 Mar 2012 15:59:46 -0700, PrecisionmachinisT wrote:
"Tim Wescott" wrote in message
...
On Wed, 21 Mar 2012 15:28:34 -0700, PrecisionmachinisT wrote:

"Tim Wescott" wrote in message
...
So, for my day job I'm working on a circuit board design to
replace something which features a heatsink made from aluminum
angle. It's 1" x 1" x 1/4", with nice square corners everywhere
(radius 0.02").

Up to now I've been blithely assuming that this is an
off-the-shelf item that I can get anywhere -- but it looks like
it may be harder to get than that. Worse, I'd really like to
extend the heat sink another 1/2" or even 1" under the board,
while keeping the outside leg at 1".

So I want to specify something that won't have their mechanical
engineers muttering under their breath _too_ much about @#$% EEs
with time on their hands...

McMaster carries aluminum angle, but it describes the inside
corner and the inside ends of the legs as "rounded", without
saying what the radius is. I can handle a radius on the inside
corner, but that radius on the leg takes away from area that I
want touching my board. Furthermore, McMaster only carries angle
with even-length sides.

So my questions a

Is there any commonly-available aluminum angle that has corners
that one wouldn't describe as "rounded"? From who?

If I must go with rounded corners, can I expect that there is a
standard? What is it? Is there a place I might find it on the
web? (Machinery's Handbook doesn't seem to list anything like
that).

Is there any commonly-available aluminum angle with uneven leg
lengths? I'm specifically looking for 1" x 1.5" x 1/4", or 1" x
2" x 1/4". From who?

Any notion of how much it might cost to have a machine shop take
a larger angle and whack it down? These need machining anyway:
they have to be cut to length, then drilled on both webs and
tapped on one -- so it would be a case of "while it's in the
machine anyway, make one or two additional cuts". Precision is
nearly nonexistent: +/- 0.05" would be fine, and finish wouldn't
be a huge issue: as long as the edges are deburred and the cut
side isn't so rough that it draws blood when handled things
would be fine; I would expect that a decent shop with even a
minimal sense of pride would insist on a much better finish than
necessary to get the job done.

"Structural" is generally 6061 and it has an inside fillet
whereas "architectural" is generally 6063 and has sharp corner.

That said, your problem probably isn't going to be finding it
with sharp corners, rather, it's going to be finding it in your
desired (1/4) in wall thickness.

Suggest try this link you just might just find something...

http://tinyurl.com/6vwjdzj

I should re-do my thermal analysis. (I.e., something more thorough
than "use what's already there"). 1/8" may be thick enough.

Additional mass does not increase thermal radiation capacity, it
only increases the amount of TIME that it takes for the unit reach
thermal equilibrium--which is only appropriate for something that
has a rigid duty cycle...otherwise you're only asking for trouble.

If you want to INCREASE BTUH CAPACITY, then either increase airflow
or increase the total amount of surface area by milling grooves or
by adding fins.

In this case the mount/heatsink's job is to carry heat from the board
to the frame of the machine. Extra thickness would, indeed, carry
that heat from the board to the mounting flange more effectively --
but I don't think that is the worst offender in the temperature-drop
sweepstakes.

--
My liberal friends think I'm a conservative kook. My conservative
friends think I'm a liberal kook. Why am I not happy that they have
found common ground?

Tim Wescott, Communications, Control, Circuits &
Softwarehttp://www.wescottdesign.com

Does the heat sink have fins? you did not seem to mention fins in the
OP. When I had to custom make heat sinks I got a bunch of roughly
matching ones (1x1 seems like a popular size) and shaved them down to
my desired size with a grinding mill (using a regular mill bends the
fins all over the place). heat sinks usually have square corners.
Digikey as you probably know has all sorts of heat sinks. I got my
batch off ebay for dirt cheap, probably from a hi tech company
liquidation.

No fins. It's really a "heat conductor", or perhaps just a thick
bracket that conveys heat. I don't know what you might call it -- but
it's not a device to better match the thermal impedance of a solid with
the thermal impedance of the air.


"heat spreader" is the engineering name I've seen occasionally applied
to parts having that function...

I'm too busy to dink around with new projects for the foreseeable future
but you might want to ask Eric for a ballpark quote...simply make from a
solid bar...

Thanks. "Heat spreader" is, indeed a term that I remember now that
you've joggled my memory.

Tim, take a look at this:

http://www.midamericaextrusions.com/...ock-shapes.pdf

Look at "Angle Unequal Legs–Square Corners," page 14

--
Ed Huntress

Hey Tim,

I was looking for something else in the shop, and I stumbled across a
piece of 3/4 X 3/4 X 1/8 wall about 18" long as you describe, no
discernible radii anywhere. You are welcome to it if it is of use.

Available as "WORK-SAVER" line of products, available at a hardware
store, but if not....

H. Paulin Co.
12400 Plaza Drive, Unit 1
Parma, OH 44130-1057
Tel: 1-216-433-7633
Fax: 1-216-433-7622

On 3/21/2012 1:32 PM, Tim Wescott wrote:
On Wed, 21 Mar 2012 13:05:05 -0500, Lloyd E. Sponenburgh wrote:

Tim fired this volley in
:

If I must go with rounded corners, can I expect that there is a
standard? What is it? Is there a place I might find it on the web?


Tim,
Have you checked smallparts.com? Most big-box home improvement centers
and ACE hardware carry a good selection of aluminum angles, some with
unequal legs.

I just bought 4' of 4"x4"x1/2" aluminum channel from MSC. They carry
other sizes, but few with unequal legs.

On the MSC metal, the INSIDE corners (all) are rounded (ends of the legs
as well as the crotch), but the outside corners are all square.

4x4x1/2" should be big enough for your little TO-220 sink, yes?

I'll take a look. It really needs to be something that's commonly
available for machine shops, though, and for the entire life of the
product -- I'm going to be specifying this to the manufacturer for whom I
am designing the board; I'm sure they'd rather not have to send out a guy
to dig through the racks at Home Depot for something that might disappear
at any moment over the next ten years or so.



You might look he
http://www.mdteam.com/index.php/prod...a-metal-sheets
Macklanburg Duncan makes these aluminum extrusions and should be readily
available through most lumber yards and box stores.

--


___________________________________

Keep the whole world singing . . .
Dan G
remove the seven

DanG fired this volley in news:jkn8ui$tm3$1
@speranza.aioe.org:

You might look he
http://www.mdteam.com/index.php/prod...a-metal-sheets
Macklanburg Duncan makes these aluminum extrusions and should be readily
available through most lumber yards and box stores.

That was already suggested to him a week ago... no bite. Odd, that,
because MD makes a whole line of very standardized extrusions you've been
able to buy since the early 1960's with no changes in the line.


Lloyd

"DanG" wrote in message
...
On 3/21/2012 1:32 PM, Tim Wescott wrote:
On Wed, 21 Mar 2012 13:05:05 -0500, Lloyd E. Sponenburgh wrote:

Tim fired this volley in
:

If I must go with rounded corners, can I expect that there is a
standard? What is it? Is there a place I might find it on the web?


Tim,
Have you checked smallparts.com? Most big-box home improvement centers
and ACE hardware carry a good selection of aluminum angles, some with
unequal legs.

I just bought 4' of 4"x4"x1/2" aluminum channel from MSC. They carry
other sizes, but few with unequal legs.

On the MSC metal, the INSIDE corners (all) are rounded (ends of the legs
as well as the crotch), but the outside corners are all square.

4x4x1/2" should be big enough for your little TO-220 sink, yes?

I'll take a look. It really needs to be something that's commonly
available for machine shops, though, and for the entire life of the
product -- I'm going to be specifying this to the manufacturer for whom I
am designing the board; I'm sure they'd rather not have to send out a guy
to dig through the racks at Home Depot for something that might disappear
at any moment over the next ten years or so.

You should go to Hadco Metals to see what is/is not standard.

Architectural is sharp-cornered, structural is round-cornered. The heaviest
in architectural is 3x3x1/4.
If you need 4x4x1/2, AND you need a sharp corner, I don't think a machine
shop would charge too much to square the inside/outside corners of
structural.

And for what MSC/HD charge, you could get whole lengths from Hadco or other
alum suppliers.
PSC in PA will cut and ship UPS, nice people.

Btw, 4x4x1/2 is really hefty stuff. I've got 2.5x2.5x1/4 structural, and
DATS hefty!!
--
EA





You might look he
http://www.mdteam.com/index.php/prod...a-metal-sheets
Macklanburg Duncan makes these aluminum extrusions and should be readily
available through most lumber yards and box stores.

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___________________________________

Keep the whole world singing . . .
Dan G
remove the seven

"Existential Angst" fired this volley in
:

If you need 4x4x1/2, AND you need a sharp corner, I don't think a
machine shop would charge too much to square the inside/outside
corners of structural.

And for what MSC/HD charge, you could get whole lengths from Hadco or
other alum suppliers.

I have a machine shop, and I needed only 4' of the heavy angle, and the
next morning.

Since I live in the boonies, not near any major cities, MSC was the
supplier of choice. In truth, they were only about 20% more expensive
than most on-line suppliers, once you figure shipping (which was a flat
$8.95).

But the OP who asked the question didn't need anything that stout; I was
ribbin' him about whether or not 4x4x1/2 would be big enough to heatsink
one TO-220 transistor or regulator.

For standard architechtural shapes in small sizes, MD is the way to go.

LLoyd