Hey, anyone got a suggestion for a 16 foot long straightedge? I'd like
to be able to use it for template routing, rather than jointing, the
edges of long panels and boards. I'm thinking an aluminum extrusion
would be the way to go.
JP

Jay Pique wrote:
Hey, anyone got a suggestion for a 16 foot long straightedge? I'd like
to be able to use it for template routing, rather than jointing, the
edges of long panels and boards. I'm thinking an aluminum extrusion
would be the way to go.
JP

Yup. Extrusions usually come in 20 ft lengths. I use a 1/4" x 6" x 12'
for roughing. It is sold by the pound. Any industrial alloy place will
have those. Usually made in Brazil.
Get the 6" wide one, because you'll need to leave room for the saw
motor to go by your clamps.

r

Hi Jay,

It all depends on the accuracy you want. Aluminum extrusions aren't
usually all that straight. As an example, I just walked out to the
shop and compared two 12 foot lengths of 6" x 3/4" by butting edges
together. There's a gap between the two that is, at it's widest point,
about 1/16". I've seen 1/4" or more gap in the past. You can expect
to do better on a table saw. If you can get a wide piece like this
(the 3/4" thickness isn't significant, 3/8" would be fine) and have an
edge milled (a shop with a large gantry mill) then you could probably
use it for some pretty accurate work. At 16', it will still be pretty
hefty, you might want them to mill out some of the interior while
they're at it.

Ed Bennett

http://www.ts-aligner.com

Jay Pique wrote:
Hey, anyone got a suggestion for a 16 foot long straightedge? I'd like
to be able to use it for template routing, rather than jointing, the
edges of long panels and boards. I'm thinking an aluminum extrusion
would be the way to go.
JP

Jay Pique wrote:

Hey, anyone got a suggestion for a 16 foot long straightedge? I'd like
to be able to use it for template routing, rather than jointing, the
edges of long panels and boards. I'm thinking an aluminum extrusion
would be the way to go.

You can't get there from here.

You could fabricate a rigid weldment, then have it machined to get a
straight edge, but then you would have to keep it in a controlled
environment to maintain it.

About 15-20K will get you started.

Lew

On Nov 29, 7:43 pm, wrote:
Hi Jay,

It all depends on the accuracy you want. Aluminum extrusions aren't
usually all that straight.

In the world of TS Alignment tools, you're right, that isn't straight.
As a saw guide, 1/32nd over a 16 foot length is probably sufficient...
even 1/16th.

[snip]
If you can get a wide piece like this
(the 3/4" thickness isn't significant, 3/8" would be fine) and have an
edge milled (a shop with a large gantry mill) then you could probably
use it for some pretty accurate work. At 16', it will still be pretty
hefty, you might want them to mill out some of the interior while
they're at it.

I use two. One is a run-of-the mill 6" x 1/4 x 12' extrusion and is
within 1/32nd.
Pinske ( http://www.pinske-edge.com ) makes a 5/16 x 5-7/8 x 150" which
is .005 TIR.
#3125150 $ 295.00 150" length

Again, not to pick at nits, but straight is a relative term.

Also, because extrusions are under tension, if you machine one side,
it'll warp like crazy...like reaction wood grown on the side of a hill.
A local machine shop, which turns propellor shafts for ships, tuned
mine to .002. Not that I needed it, but the guy was obsessional. What
is more important, IMHO, is that the sides are parallel so when you
flip the _fence_, you lose the error.

On Nov 29, 7:43 pm, wrote:
Hi Jay,

It all depends on the accuracy you want. Aluminum extrusions aren't
usually all that straight. As an example, I just walked out to the
shop and compared two 12 foot lengths of 6" x 3/4" by butting edges
together. There's a gap between the two that is, at it's widest point,
about 1/16". I've seen 1/4" or more gap in the past. You can expect
to do better on a table saw. If you can get a wide piece like this
(the 3/4" thickness isn't significant, 3/8" would be fine) and have an
edge milled (a shop with a large gantry mill) then you could probably
use it for some pretty accurate work. At 16', it will still be pretty
hefty, you might want them to mill out some of the interior while
they're at it.

I could probably live with a 32nd over 16 feet. If I did get a 3/8 x 6
x 192" piece of aluminum that was staight, or had it milled straight,
would it stay that way? I'm guessing it would be pretty whippy to move
around. Maybe I could loosely mount a wooden reinforcement to it or
something. Maybe coupling a pair of 8 footers together, and then
having the whole thing milled would be the way to go. I dunno. I'm
not too confident in the accuracy of manhandling a 16 foot, 24" wide
plank over a jointer!
JP

Jay Pique wrote:

I could probably live with a 32nd over 16 feet. If I did get a 3/8 x 6
x 192" piece of aluminum that was staight, or had it milled straight,
would it stay that way?

Oh ... now you want durability too? ;-)

When you carry / store that aluminum, never let the 'straight' edge face
either up or down without support under it. All straightness will be but
a memory the next time you try to use it.

You might consider getting a section of box channel iron and having it
surface ground square in a machine shop with a big surface grinder. But
I wouldn't. How would I get it back home and down into my basement sop
without losing all that expensive straightness?

Me? If I was going this route I'd probably rip a couple widths off some
3/4" plywood and lap joint / dowel them, using a third section to line
up the joint.

But I'm new here so what do I know?

Bill
--
If God didn't exist, there would be no need for atheists.

Bill, you have presented probably the best approach. Getting a piece of
aluminum or steel that size and having it machined presents a few problems.
Finding a shop with a milling machine that big is going to be a challenge
in most places. If you do find one, they will likely charge $150.00 per hour
for the milling. Milling one edge will release stresses causing it to warp.
Milling the opposite edge may well warp it back but, chances are, milling
and flipping a couple of times will be needed. Minimum of $300.00 shot.
Milling away material to lighten it will likely make the problem worse
unless done equally on both sides. We're up in the neighborhood of $600.00
now. The idea of grinding a piece of steel presents the same problems. In
addition to that, in my 20 years of machining, I have never seen a grinder
that big though you may find someone with a grinding head on a big mill or
planer. After it is all done, you have the transport and storage problem
Bill mentioned. Do the wood, much more practical.

"Bill in Detroit" wrote in message
...
Jay Pique wrote:

I could probably live with a 32nd over 16 feet. If I did get a 3/8 x 6
x 192" piece of aluminum that was staight, or had it milled straight,
would it stay that way?

Oh ... now you want durability too? ;-)

When you carry / store that aluminum, never let the 'straight' edge face
either up or down without support under it. All straightness will be but
a memory the next time you try to use it.

You might consider getting a section of box channel iron and having it
surface ground square in a machine shop with a big surface grinder. But
I wouldn't. How would I get it back home and down into my basement sop
without losing all that expensive straightness?

Me? If I was going this route I'd probably rip a couple widths off some
3/4" plywood and lap joint / dowel them, using a third section to line
up the joint.

But I'm new here so what do I know?

Bill
--
If God didn't exist, there would be no need for atheists.

CW wrote:
Bill, you have presented probably the best approach.

Thank you. Even a blind dog finds a bone once in a while.

now. The idea of grinding a piece of steel presents the same problems. In
addition to that, in my 20 years of machining, I have never seen a grinder
that big though you may find someone with a grinding head on a big mill or
planer. After it is all done, you have the transport and storage problem



There's one in Troy, MI (used it to grind robot platforms) and another
in Farmington, MI. Bound to be others somewhere. Table moves, head is
stationary. BIG BUCKS for a surface grinder that needed roughly 40 feet
just to cycle back and forth. ;-)

I want the contract to scrape it back to true when the bedways wear. ;-)

We welded up the pads, machined, keyed and assembled them then had them
ground as an assembly.

The place in Farmington was an 89 day shop I made 87 days in. They fired
three mill hands, hired me, let me work for 87 days and then told me
that I was incompetent.

They're probably right. If I had known how to handle that part of the
trade I'd have recognized them for the type of shop they are and never
have tried to stick it out there.

Franklin Forge, ISTR.

Bill

--
If God didn't exist, there would be no need for atheists.

What about a few of these from Lee Valley.. I am not sure but I would
think that you could join more than two together to get to the length
that you want...

http://www.leevalley.com/wood/page.a...240,45313&ap=1

A.

Bill in Detroit wrote:
CW wrote:
Bill, you have presented probably the best approach.

Thank you. Even a blind dog finds a bone once in a while.

now. The idea of grinding a piece of steel presents the same problems. In
addition to that, in my 20 years of machining, I have never seen a grinder
that big though you may find someone with a grinding head on a big mill or
planer. After it is all done, you have the transport and storage problem



There's one in Troy, MI (used it to grind robot platforms) and another
in Farmington, MI. Bound to be others somewhere. Table moves, head is
stationary. BIG BUCKS for a surface grinder that needed roughly 40 feet
just to cycle back and forth. ;-)

I want the contract to scrape it back to true when the bedways wear. ;-)

We welded up the pads, machined, keyed and assembled them then had them
ground as an assembly.

The place in Farmington was an 89 day shop I made 87 days in. They fired
three mill hands, hired me, let me work for 87 days and then told me
that I was incompetent.

They're probably right. If I had known how to handle that part of the
trade I'd have recognized them for the type of shop they are and never
have tried to stick it out there.

Franklin Forge, ISTR.

Bill

--
If God didn't exist, there would be no need for atheists.

You would need to do your own research on the degree of accuracy,
but these must be fairly accurate as they are used for highway
department and high f-number concrete work. They go up to 24
feet.

http://www.bontool.com/product1.asp?P=MAGSCREEDS
___________________________
Keep the whole world singing. . . .
DanG


"Jay Pique" wrote in message
oups.com...
Hey, anyone got a suggestion for a 16 foot long straightedge?
I'd like
to be able to use it for template routing, rather than jointing,
the
edges of long panels and boards. I'm thinking an aluminum
extrusion
would be the way to go.
JP

You might try a metals junkyard. They sometimes have lengthy aluminum
extrusions (Architectural shapes with rectangular cross sections)
salvaged from office buildings which are being torn down. The cost
would based on weight and probably more economical than any new
provider.
Jay Pique wrote:
Hey, anyone got a suggestion for a 16 foot long straightedge? I'd like
to be able to use it for template routing, rather than jointing, the
edges of long panels and boards. I'm thinking an aluminum extrusion
would be the way to go.
JP

Robatoy wrote:

In the world of TS Alignment tools, you're right, that isn't straight.
As a saw guide, 1/32nd over a 16 foot length is probably sufficient...
even 1/16th.

True, but my quick test wasn't very rigorous. I don't know if the two
pieces bent in oposite directions or the same direction (one less than
the other). At 65 lbs each I was too lazy to try all the various
combinations.

I use two. One is a run-of-the mill 6" x 1/4 x 12' extrusion and is
within 1/32nd.
Pinske ( http://www.pinske-edge.com ) makes a 5/16 x 5-7/8 x 150" which
is .005 TIR.
#3125150 $ 295.00 150" length

Very interesting! I never knew that these existed. I wonder how well
that 0.005" spec holds up over time. Probably only good lying flat.
Such a long piece would sag quite a bit on edge.


Again, not to pick at nits, but straight is a relative term.


Absolutely. And, it's quite refreshing to hear someone say that.
There are only degrees of accuracy, nothing is perfect.

Also, because extrusions are under tension, if you machine one side,
it'll warp like crazy...like reaction wood grown on the side of a hill.
A local machine shop, which turns propellor shafts for ships, tuned
mine to .002. Not that I needed it, but the guy was obsessional. What
is more important, IMHO, is that the sides are parallel so when you
flip the _fence_, you lose the error.

Very true. Extrusions do have a lot of internal stress. Machining the
thin edge of a wide piece isn't likely to cause nearly as much trouble
as facing one of the broad sides. Still, it would need to be checked
after machining. Anybody with a mill that can handle pieces 144" (or
even 150"!) won't have any trouble doing the job right.

The local rate for raw aluminum extrusions is $3.99/lb. My 3/4" x 6" x
144" pieces cost me nearly $260 each at the local metals supply. I
would expect a 3/8" piece to cost about $130, a 1/4" piece should be
around $87. Given the machine work, the Pinske straight edges look
like quite a bargain to me. It sounds like just the thing for the OP
if he doesn't want to take his chances with a raw extrusion.

Ed Bennett

http://www.ts-aligner.com

You would need to handle it pretty carefully. It would have a tendency
to sag if you stood it on edge. If you left it that way for too long
it would definitely lose its shape. Best to store it lying flat. And,
you'll need to be careful not to ding the edges. Aluminum is pretty
soft. And, it would be best if it were kept in an environment with
relatively stable temperatures.

Joining pieces is much easier said than done. I wouldn't expect it to
be a good solution. Best to stick with one long piece.

Ed Bennett

http://www.ts-aligner.com

Jay Pique wrote:

I could probably live with a 32nd over 16 feet. If I did get a 3/8 x 6
x 192" piece of aluminum that was staight, or had it milled straight,
would it stay that way? I'm guessing it would be pretty whippy to move
around. Maybe I could loosely mount a wooden reinforcement to it or
something. Maybe coupling a pair of 8 footers together, and then
having the whole thing milled would be the way to go. I dunno. I'm
not too confident in the accuracy of manhandling a 16 foot, 24" wide
plank over a jointer!
JP