I have about 25 sheets of Fabral MightyRib that I need to cut.

http://www.fabral.com/products/mighti-rib-pbr

Some, I need to cut in half on the ninety, others, I need to cut into about
two feet long pieces, with one end diagonal.

I have a compound radial saw that I think could be set up on top of my 4' x
10' welding table, and bolted down. A feed made up of roller stands would
hold the material, and it could be clamped in place.

A metal cutting blade would have to spin slower than the speed of this saw.
Can I use a dimmer to slow the blade down, or would that screw up the saw/

Any other ideas how to cut these? I do have a DW890 sheet metal cutter, but
where there are ribs, it will not follow the contour very easily. I COULD
use a 7" circular saw at those points, it would just be a lot of work.

And what about kickback?

TIA

Steve

"Steve B" fired this volley in
:

Any other ideas how to cut these? I do have a DW890 sheet metal
cutter, but where there are ribs, it will not follow the contour very
easily. I COULD use a 7" circular saw at those points, it would just
be a lot of work.


Although the Galvalume guys will tell you that using anything but a shear
voids the warantee, almost all the professional pole barn constructors in
this neck of the woods use a diamond saw to cut 5-vee, and standing-rib
barn metal. It works pretty well, if very noisily.

The reason the manufacturers say it's bad to saw is because a shear tends
to wipe the plated layers across the cut, while a saw (supposedly) leaves
the end clean and bare.

I use a power shear (Malco "Turbo-Shear" drill attachment). It's a tiny
bit of a chore moving up and down ribs, but not as bad as you might
think. The nose of the cutter has a geometry that allows you to follow
the ribbing without much distortion.

LLoyd

"Steve B" wrote in message
...
I have about 25 sheets of Fabral MightyRib that I need to cut.

http://www.fabral.com/products/mighti-rib-pbr

Some, I need to cut in half on the ninety, others, I need to cut into
about two feet long pieces, with one end diagonal.

I have a compound radial saw that I think could be set up on top of my 4'
x 10' welding table, and bolted down. A feed made up of roller stands
would hold the material, and it could be clamped in place.

A metal cutting blade would have to spin slower than the speed of this
saw. Can I use a dimmer to slow the blade down, or would that screw up the
saw/

Is it a universal brush motor? If so you can reduce speed with a router
speed control rated for the current of the saw. If it's an AC induction
motor then no.

I tried some experiments with "light dimmers" and felt they didn't work very
well for motor speed control, but then I didn't know that AC induction
motors don't like to be speed controlled that way.

Roller stands and roller tables are awesome tools to have. I use mine for
all kinds of things. I wish I had a couple more.... and a better place to
store them. LOL.

"Bob La Londe" fired this volley in
:

Roller stands and roller tables are awesome tools to have. I use mine
for all kinds of things. I wish I had a couple more.... and a better
place to store them. LOL.

DON'T store them, Bob. Dedicate a couple to every tool, and leave them up!
G

LLoyd

"Bob La Londe" wrote in message
...
"Steve B" wrote in message
...
I have about 25 sheets of Fabral MightyRib that I need to cut.

http://www.fabral.com/products/mighti-rib-pbr

Some, I need to cut in half on the ninety, others, I need to cut into
about two feet long pieces, with one end diagonal.

I have a compound radial saw that I think could be set up on top of my 4'
x 10' welding table, and bolted down. A feed made up of roller stands
would hold the material, and it could be clamped in place.

A metal cutting blade would have to spin slower than the speed of this
saw. Can I use a dimmer to slow the blade down, or would that screw up
the saw/

Is it a universal brush motor? If so you can reduce speed with a router
speed control rated for the current of the saw. If it's an AC induction
motor then no.

I tried some experiments with "light dimmers" and felt they didn't work
very well for motor speed control, but then I didn't know that AC
induction motors don't like to be speed controlled that way.

Roller stands and roller tables are awesome tools to have. I use mine for
all kinds of things. I wish I had a couple more.... and a better place to
store them. LOL.

I did find a foot control for a sewing machine today. Would that work? And
how do I tell if it is an induction motor or a universal brush?

I feel stupid asking that, but I'm merely ignorant, never having been told
about this before.

Steve

"Steve B" wrote in message
...
..
...And how do I tell if it is an induction motor or a universal
brush?

Steve

Universal motors normally spark inside. Induction motors normally
don't.

jsw

On 2012-05-29, Steve B wrote:
I have about 25 sheets of Fabral MightyRib that I need to cut.

http://www.fabral.com/products/mighti-rib-pbr

Looks nasty to cut.

[ ... ]

I have a compound radial saw that I think could be set up on top of my 4' x
10' welding table, and bolted down. A feed made up of roller stands would
hold the material, and it could be clamped in place.

A metal cutting blade would have to spin slower than the speed of this saw.
Can I use a dimmer to slow the blade down, or would that screw up the saw/

I think that most radial arm saws, and hand held circular saws
as well, are brush equipped universal motors. Those should do pretty
well with a dimmer -- or even better with a speed controller which
senses back EMF between the pulses to determine speed and adjusts the
power to try to maintain that speed.

But this won't do much for the needed torque. A saw *made* for
this would have a mechanical way to slow down the motor -- such as
perhaps a worm gear. That boosts torque while cutting speed.

However, if you have no brushes (consult the diagram in your
manual if you can't find external brush caps), it will not work well at
all.

Any other ideas how to cut these? I do have a DW890 sheet metal cutter, but
where there are ribs, it will not follow the contour very easily. I COULD
use a 7" circular saw at those points, it would just be a lot of work.

Frankly, I have no idea. I can imagine the makers have a custom
shear which follows the contours -- but that would be good for just a
90 degree cut -- or they might have another for 45 degree and maybe even
30 and 60 degree cuts -- depends on what the demand is.

Do they offer suggestions as to how to cut it?

And what about kickback?

I, personally, would be very worried about that. The only thing
which might make it somewhat safer is the loss of torque because of your
speed control. :-)

Good Luck,
DoN.

--
Remove oil spill source from e-mail
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On 2012-05-29, Steve B wrote:

"Bob La Londe" wrote in message
...

[ ... ]

I did find a foot control for a sewing machine today. Would that work?

Probably not well at all. Sewing machine motors are very low
horsepower, compared to circular saws. (Something like 1/10th vs 1 HP
or so -- more for larger blade diameters.)

And
how do I tell if it is an induction motor or a universal brush?

1) Look for insulated screw-in caps on the outside which allow you
to inspect and change the brushes. (They wear out over time.)
They should be about in line with the end of the rotor where the
commutator would be, if you know what those are.

2) If you can't find screw-in caps (probably a cheaper saw), look
in the manual (download it from the maker's site if you can't
find the one which came with it) and look at the diagram. If
you know what motor brushes look like, you should be able to
recognize them in the drawing. If you don't, spend time reading
through the parts list which accompanies the manual looking for
the word "brush" or "brushes".

I feel stupid asking that, but I'm merely ignorant, never having been told
about this before.

And you've never had a power tool quite working because the
brushes are worn out, either? If all your tools are new, maybe not. If
you get old ones, and they start acting flakey, they probably need new
brushes (very cheap repair items), and the commutator may need to be
turned and (perhaps) the mica in the grooves undercut.

But I really don't think that this will be very satisfactory
even with a speed control. If you want to cut at slow speeds, you need
to gear the speed down and the torque up -- e.g. use a motor designed to
run that kind of saw blade.

Good Luck,
DoN.

--
Remove oil spill source from e-mail
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On 5/30/2012 1:47 AM, Lloyd E. Sponenburgh wrote:

the Galvalume guys will tell you that using anything but a shear
voids the warantee,

I was told it's the heat harms the coating, so only cold cutting should
be done.
You could rough cut say one inch out from the desired line, then cut to
line with manual snips.

Jordan

On Tue, 29 May 2012 14:51:08 -0700, "Steve B"
wrote:


I feel stupid asking that, but I'm merely ignorant, never having been told
about this before.

Definitely not stupid, Steve, you know that you don't know, so you
are intelligently asking for help. A real dummy would go ahead
without asking.

For cutting corrugated, I use a metal cut off disc in a 9 1/4 saw
or for smaller stuff a 1 mm disc in an angle grinder. Lotsa noise &
sparks, watch for grass or other combustibles. I has a grass fire
start from 6 metres away, all around where I was working was bare
soil.

Alan

wrote in message
...
...
For cutting corrugated, I use a metal cut off disc in a 9 1/4 saw
or for smaller stuff a 1 mm disc in an angle grinder. Lotsa noise
&
sparks, watch for grass or other combustibles. I has a grass fire
start from 6 metres away, all around where I was working was bare
soil.
Alan

I bought an old Sears table saw with the blade arbor pulley safely
outside the base housing to use for sawing sheet metal with abrasive
cutoff disks. The table tilts rather than the blade, making it very
inconvenient for sheets of plywood.

The motor is under the plate the saw mounts on, protected from the
stream of sparks. It's weight tensions the belt so it lifts when the
blade jams. The fine adjustment is a rubber hockey puck wedged under
the hinged motor plate. I raised the saw base on blocks so I can blow
out all the sawdust before cutting sheetmetal.

If the cut edge is up, under another sheet or the ridge cap, the LPS3
I spray on it is enough to minimize rusting where the zinc has been
burned. Otherwise I cut the sheets with an air shear like this.
http://www.compresoresyherramientasd...m)_gp-838c.jpg
and lotsa hand pressure.

If you or storms mess up the corrugations you can reshape them over 2"
pipe with a plastic hammer:
https://picasaweb.google.com/KB1DAL/...85907089791234
https://picasaweb.google.com/KB1DAL/...85348223415954
https://picasaweb.google.com/KB1DAL/...83909402381154

jsw

In article , Jordan
wrote:

On 5/30/2012 1:47 AM, Lloyd E. Sponenburgh wrote:

the Galvalume guys will tell you that using anything but a shear
voids the warantee,

I was told it's the heat harms the coating, so only cold cutting should
be done.
You could rough cut say one inch out from the desired line, then cut to
line with manual snips.

Jordan

I have a blade I purchased years ago for my 7 1/4 Skill. It looks like a
diamond blade,but isn't. It has approx 5/8" deep slots every 30 deg.or
so. It works great for all types of sheet metal products. It's not
around now or I would try and see the mfg.
CP

Pilgrim fired this volley in newsilgrim-
:

I have a blade I purchased years ago for my 7 1/4 Skill. It looks like
a
diamond blade,but isn't. It has approx 5/8" deep slots every 30 deg.or
so. It works great for all types of sheet metal products. It's not
around now or I would try and see the mfg.

It's a "ferrous metal cutting blade". It's nothing more than a circle of
High Speed Steel with some notches. I have a couple.

They cut by friction, alone, and work fine, so long as you're not trying
to preserve a finish, or avoid burrs on the cut line (which they leave in
abundance).

LLoyd

I put them on my CNC plasma machine and just do up's and downs
as I cut the sheet.

Martin

On 5/30/2012 5:52 AM, wrote:
On Tue, 29 May 2012 14:51:08 -0700, "Steve
wrote:


I feel stupid asking that, but I'm merely ignorant, never having been told
about this before.

Definitely not stupid, Steve, you know that you don't know, so you
are intelligently asking for help. A real dummy would go ahead
without asking.

For cutting corrugated, I use a metal cut off disc in a 9 1/4 saw
or for smaller stuff a 1 mm disc in an angle grinder. Lotsa noise&
sparks, watch for grass or other combustibles. I has a grass fire
start from 6 metres away, all around where I was working was bare
soil.

Alan

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote


It's a "ferrous metal cutting blade". It's nothing more than a circle of
High Speed Steel with some notches. I have a couple.

They cut by friction, alone, and work fine, so long as you're not trying
to preserve a finish, or avoid burrs on the cut line (which they leave in
abundance).

LLoyd

So, Lloyd, is this a diamond blade, or just a blade with some sort of
coating or do the notches do the cutting? Might this be something the Borg
would stock? It sounds like what I need.

Steve

"Steve B" fired this volley in
:

So, Lloyd, is this a diamond blade, or just a blade with some sort of
coating or do the notches do the cutting? Might this be something the
Borg would stock? It sounds like what I need.

No, just a disk of HSS. The notches simply provide room so as the edge
expands, the blade doesn't cup or warp when it gets hot. It cuts purely
by friction heating getting the work metal hot enough to scrape away.
They count on the red-heat hardness of high-speed steel to make it
survive the red-heat softness of the sheet metal you're cutting.

You have to run them fast (rotation rate), and apply pretty good pressure
to get them to cut... no diddling in the work.

The Borg would normally stock them. Sometimes even my local ACE does.
Sears always did, too.

LLoyd

On Thu, 31 May 2012 12:15:00 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

"Steve B" fired this volley in
:

So, Lloyd, is this a diamond blade, or just a blade with some sort of
coating or do the notches do the cutting? Might this be something the
Borg would stock? It sounds like what I need.

No, just a disk of HSS. The notches simply provide room so as the edge
expands, the blade doesn't cup or warp when it gets hot. It cuts purely
by friction heating getting the work metal hot enough to scrape away.
They count on the red-heat hardness of high-speed steel to make it
survive the red-heat softness of the sheet metal you're cutting.


Plus, the heat of friction introduced into the disk is distributed
*around* the entire disk, while the roughly equivalent heat of
friction in the work is concentrated at the spot you're cutting.


You have to run them fast (rotation rate), and apply pretty good pressure
to get them to cut... no diddling in the work.

The Borg would normally stock them. Sometimes even my local ACE does.
Sears always did, too.

LLoyd

On 6/1/2012 4:25 AM, Ed Huntress wrote:

Plus, the heat of friction introduced into the disk is distributed
*around* the entire disk, while the roughly equivalent heat of
friction in the work is concentrated at the spot you're cutting.



I've heard that, with aluminised corrugated sheets (I think that's what
we're talking about?), too much heat can damage the coating, to the
extent that its rust preventing action is compromised.
It's made me too nervous to use a friction cut, except for real
galvanised steel sheeting. Then, a steel circular saw blade mounted
backwards serves OK - something I learnt here.
Or as mentioned, friction cut an inch outside the finished line and trim
with hand snips.

On Fri, 01 Jun 2012 08:58:57 +1000, Jordan wrote:

On 6/1/2012 4:25 AM, Ed Huntress wrote:

Plus, the heat of friction introduced into the disk is distributed
*around* the entire disk, while the roughly equivalent heat of
friction in the work is concentrated at the spot you're cutting.



I've heard that, with aluminised corrugated sheets (I think that's what
we're talking about?), too much heat can damage the coating, to the
extent that its rust preventing action is compromised.
It's made me too nervous to use a friction cut, except for real
galvanised steel sheeting.

Not having done it, I don't know how much damage it does to the
coating. Keep in mind, though, that the zinc on galvanized steel melts
at a significantly lower temperature than aluminum -- several hundred
degrees F lower.

If you get steel hot enough to melt, any zinc on it is hot enough to
vaporize. That's not true with aluminum.

I suspect that any damage is confined to an area pretty close to the
cut. But that steel is now somewhat oxidized, and the coating is, too.
So any rust-proofing repair -- with zinc chromate paint, or
zinc-loaded epoxy -- isn't going to stick unless you clean it well.

--
Ed Huntress

Then, a steel circular saw blade mounted
backwards serves OK - something I learnt here.
Or as mentioned, friction cut an inch outside the finished line and trim
with hand snips.

Jordan fired this volley in news:jq8t3g$cmo$1
@speranza.aioe.org:

Or as mentioned, friction cut an inch outside the finished line and trim
with hand snips.


Only that last preserves the plating. Even the backwards carbide blade
both heats and completely bares the cut end.

Lloyd

Ed Huntress fired this volley in
:

I suspect that any damage is confined to an area pretty close to the
cut. But that steel is now somewhat oxidized, and the coating is, too.
So any rust-proofing repair -- with zinc chromate paint, or
zinc-loaded epoxy -- isn't going to stick unless you clean it well.

Power shears are really the way to go. Those I picked up at the siding
supplier work a treat, and are only a tiny chore to get over ribs.

Lloyd

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
. 3.70...
"Bob La Londe" fired this volley in
:

Roller stands and roller tables are awesome tools to have. I use mine
for all kinds of things. I wish I had a couple more.... and a better
place to store them. LOL.

DON'T store them, Bob. Dedicate a couple to every tool, and leave them
up!
G

Well.... back when I had money I put up a 3000sqft warehouse next to my
house. Figured it would have room for a small office, storage for my
communications contracting business, room for my 3 trucks and 2 boats and a
little space in the back for wrenching on trucks and boats if times got
tough and I had to do my own work again.

Now that I don't have money I wish I had put up 6000 sq ft back when I did
have money. I never in my wildest dreams would have thought I would be
setting up a small shop much less a small machine shop and doing as much
work in the warehouse as I do in the field.

I am using every bit of it, and I only manage to keep one boat and one truck
inside now. My new service truck sits outside.

If I ever get around to finishing the office that will help some. I'll get
a stack of drywall out of the way, and move a lot of the shiny purty parts
out of the warehouse into the front office.

I'm also considering putting in some mezzanines to move some storage to a
second level. I have a 16' eve height so a 7' or 8' mezzanine in 1/2 the
shop would work out ok.... if I only had the money. LOL.