Official Luthiers Forum!

I had some people ask me how I cut my Aluminum for jigs and how to cut sheet metal for resos if you don't have a shear. Well this is how I've been doing it.

Thanks Chris! You da man

_________________
Ken

Very cool Chris!
I've cut aluminum and brass before but never thought about cutting steel, will come in handy from time to time.

Thanks,
Joe

When I worked in the rolling mills they use to cut 6 X 6 angle, channel and I beams with 4' saw blades. They also make a 12" blade for a miter saw that will cut heavy steel. It's about a $130 blade. I used one at work once for even cutting 3" rigid conduit and angle. It was pretty strange cutting it even so. My concern with cutting anything heavier the sheet metal steel with these blades is with the teeth coming off and going a flying. The blade designed for the heavy steel are just square teeth and not angled.
I know that carpenders use to turn blades around in their circular saws to cut Aluminum sofit to size in the old days.

In the steel mill (US Steel Clairton Works) they sharpened the 4' blade on a machine that used a fibre cutting disc
http://www.ykgoodwill.com/products2.asp ... %3E323-%3E
to cut the teeth into the blade. The blade was just some type of harden steel and it mounted on the machine that would rotate the blade about 3/4" and the cutter with the fiber blade would just plunge down and make the tooth cut. Pretty simple actually. That was the tool room guy's job to sharpen the blades. They also use to have what was called the slow speed saw which was exactly that a 4' X 1" blade that ran slow and each tooth that was cut at a pitch would just mill off the steel . They use it on certain large flats that couldn't be cut with a torch for reasons I'm guessing would mess with the temper specs or something.
Here's some metal cutting blades designed for some heavier steel.
http://www.maxtool.com/index/wm_carbides.asp
You can also google it for more.

Cutting steel on a table saw can cause a fire. The sparks can ignite the sawdust on the undercarriage of the saw, and also inside the dust collector system.
The real danger is that the sparks can cause a slow smoldering condition that can erupt into a blazing fire some time later when you are no longer in the vicinity.

Ray

While your at the depot get yourself a full face shield too. I got one a while back and just hang it on the saw easy enough to pop it on and make a cut.
Good tip on the steel and fire. I don't use the dust collector with metals. Just let it drop on the floor and vacuum it up later. I have an open bottom contractors type saw.

A good thing to remember. Whenever I cut metal on my saws I do two things - vacuum the sawdust up and turn off the dust collector.

_________________
Steve Smith
"Music is what feelings sound like"

I sell both the metal cutting saws and the carbide toothed blades . KEEP IN MIND the saws designed for cutting STEEL are a slower RPM than a standard saw . ALuminum and brass are NO problem . However Steel is dangerous if the carbide comes off because of a higher RPM than is recommended it is like a bullet .

_________________
The Shallower the depth of the stream , The Louder the Babble !
The Taking Of Offense Is the Life Course Of The Stupid One !
Wanna Leave a Better Planet for our Kids? How about Working on BETTER KIDS for our Planet !
Forgiveness is the ability to accept an apology that you will probably NEVER GET
The truth will set you free , But FIRST, it will probably Piss you Off !
Creativity is allowing yourself to make Mistakes, Art is knowing which ones to Keep !
The Saddest thing anyone can do , is push a Loyal Person to the point that they Dont Care Anymore
Never met a STRONG person who had an EASY past !
http://wiksnwudwerks.blogspot.com/
http://www.facebook.com/groups/GatewayA ... rAssembly/

The real saws for cutting steel with a carbide blade are the cold saws. They spin at a slow speed that mills the material off leaving almost a burr free finish. If somebody is grabbing a dull sawblade and running it at high speed through, say 1/2" mild steel, what you are doing is more like friction cutting. Friction cutting relies on pre heating the material and plasticizing the material so it can be removed. Before someone gets hurts you need to remember that the 2 enemies of carbide are heat and shock. Couple that with the fact that the teeth are brazed onto the blade and you have a situation that can be a crap shoot for safety. It can be done........most the time.
I've done enough friction cutting over the years to know that is probably the least safe and scariest operation in a shop. There is absolutely no finesse involved, just speed, power, and force. Keep the red dot on the line and don't stop. If the saw blade happens to break 1/2 way through your screwed.
With good backing you should be able to cut sheet metal OK. Not sure if I'd be grabbing larger size steel to cut on a table saw though. Bandsaw at a slower speed works just fine for me.

Tim

This is absolutely correct . The brand saw I sell is scotchman coldsaws , they run at general speed of 22/44 rpm and use a HSS blade . The carbide toothed blades for Chopsaws and Hand saws " evolution Brand" are running at about 1/2 the rpm of a standard saw . This is where the danger lies . can it be done yes . Do alot of people do it yes . would I do it NO . Proper tool for proper job. again brass and aluminum ok . .... Steel , .... well .... be carfull if you do it.

Also , if the sheet metal binds up and kicks back at you , you now have " basically " a thin dull knife blade comming at you out of the saw . This would apply to Aluminum and brass as well , so have a good solid hold down and protection if you choose to do this .

Please be carefull .

_________________
The Shallower the depth of the stream , The Louder the Babble !
The Taking Of Offense Is the Life Course Of The Stupid One !
Wanna Leave a Better Planet for our Kids? How about Working on BETTER KIDS for our Planet !
Forgiveness is the ability to accept an apology that you will probably NEVER GET
The truth will set you free , But FIRST, it will probably Piss you Off !
Creativity is allowing yourself to make Mistakes, Art is knowing which ones to Keep !
The Saddest thing anyone can do , is push a Loyal Person to the point that they Dont Care Anymore
Never met a STRONG person who had an EASY past !
http://wiksnwudwerks.blogspot.com/
http://www.facebook.com/groups/GatewayA ... rAssembly/

Also, if you are using a fence, you need to make sure that the fence is tight to the table. If the thin material slips under the fence you will have a problem- binding/kickback.

Cutting metal on the tablesaw is scary. I use a Freud non-ferrous blade for brass/aluminum with a sliding carriage, with good hold-downs for the stock being cut. Gloves and full face shield and standing to one side. There are a lot of flying metal chips.

Be careful!

John

You're correct about the fence. If you look in the video I have a polycarbonate aux. fence because my fence doesn't sit flush with the table.

Yeah....that might be the most dangerous way to cut metal that I can conceive of. Using the miter guide is safer than sliding metal along the rip fence but any kind of binding will put a far higher point load on the teeth and blade in general. Think shrapnel.

In a commercial metal shop, if it's too big to cut with a stationary chop saw it goes on an articulating bandsaw of some kind. Moving a blade against secured metal is far preferred to moving metal against a blade. When the situation requires metal to be moved against a blade the metal is secured to an articulating table.

To do what you are attempting, I would make a large, simple square frame with 2 x 4 and a 1" plywood bottom and devise a way to clamp your metal to the inside of that box. Then screw some rails to the bottom of the box that run in your table grooves. This will be consideraby safer than the video I just watched.

Also, as stated, if you are going to do this then use the smallest diameter blade you can in order to decrease surface speed at the tooth. I don't what the rpm of that saw is but carbide will last quite a bit longer when it's actually cutting rather than scraping homogenous materials such as aluminum and steel. One sure way to dull a carbide blade is to have it cut sheet metal as depicted in the video. Basically, carbide is hard and brittle so it likes cutting through a stable media...but the introduction of vibration greatly increases the propensity to microchip (dull). If there is no other way to do it I get why you're cutting it on the table saw.....but that looks like a nice blade that you'll need for later.

_________________
I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

Hopefully this is not a hijack:

I've got to cut about 55 pieces of 3/16" aluminum rod to the same exact length and was planning on using the table saw with like a cross cut sled type of thing with one of those toggle clamps to hold down the small piece. The pieces are short - about 2/3rds of them will be around an inch long and the other 1/3 about 1/2". I've got a pretty old carbide combination blade I was going to use for this and then I think it's time for it to retire.

Does anything there sound drastically unsafe?

_________________
http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

It's a $14 blade from the depot. Myself, anything thicker then sheetmetal in steel I use a hacksaw ,bandsaw or sawsall.
Cutting Aluminun is less scary then cutting or ripping 2" hardwood. Although I haven't ripped anything over 1/2" X 12" plate and 1" square bar stock. Take the feed a little slower and let the blade cut and take all the precautions you take when cutting anything on the table saw. I've also used a router with a 1/8" - 4 flute carbide end mill to cut brass (GS) for Resos. Messy and noisy and you'll get about a back and top and sound holes and well to a mill.
You can see in the video that it cuts the 1/4" Alu. bar and the 22 gage like butter. You want a zero clearance on the side and at the front too if you can.

If it's short pieces or round rod I'd make a miter box style jig with a stop and use a sawsall or a bandsaw or something else. Holding rod is tuff unless you have a collet vise. I've cut bundles of 10 of emt conduit to 3' length by duct tapping the bundle together tightly at each side of the cut and cut it with a portaband saw. But that's no precise.
I've cut 1 1/2" X 1/4" brass pins for centerline finders with a jig and sawsall and finished up the cut ends on a belt sander.
It's also possible with something like 1/4" rod to feed it to fast and lock catch the hook of the blade. I'd would try another type of saw is the bottom line.

I should mention that the reason I posted this video is a friend wanted to thin the width of the sides that he had cut for a metal reso so I told him that he didn't need to find a shear for that and that the diablo would be fine. I wouldn't go into commercial production mood with it but for small jobs and occational cuts get yourself a dedicated blade if you want.

That's what I made for myself when I had to cut up a bunch of 1/8" aluminum plate. It took an hour or less, and saved a lot of tense moments. You still have to pay attention to the cut, even with a proper carriage.

For cutting aluminum/brass/bronze rod and tube, I use the non-ferrous blade in the chop saw. Usually I have to make a new backing board/box to support the work properly. Sloww cutting, face shield, gloves, long sleeves.

Cheers
John

That's EXACTLY right!

_________________
I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

Not to me ! round rod is hard to hold to keep from spinning and if a piece falls and spins wrong and hits the blade you have potential shrapnel. The toggel clamps might woork , just not sure . I would be carefull . they tend to pop open sometimes. I cut stuff like that in a chopsaw with a carbide blade and make sure it is clamped BOTH SIDES for safety . once the cut is made then unclamp both sides and move parts . will take alot longer but its safer

_________________
The Shallower the depth of the stream , The Louder the Babble !
The Taking Of Offense Is the Life Course Of The Stupid One !
Wanna Leave a Better Planet for our Kids? How about Working on BETTER KIDS for our Planet !
Forgiveness is the ability to accept an apology that you will probably NEVER GET
The truth will set you free , But FIRST, it will probably Piss you Off !
Creativity is allowing yourself to make Mistakes, Art is knowing which ones to Keep !
The Saddest thing anyone can do , is push a Loyal Person to the point that they Dont Care Anymore
Never met a STRONG person who had an EASY past !
http://wiksnwudwerks.blogspot.com/
http://www.facebook.com/groups/GatewayA ... rAssembly/

Andy-
One possibility would be to drill a 3/16 hole through a hardwood block and glue/screw the block to your sliding sled.
After it is all attached, cut through the block with your saw- this would support the rod on both sides of the blade and keep things under control. You could incorporate a stop for repeating the length quite easily.
As WudWerkr said, stop after each cut and clear. You don't want chunks of rod lying around on the saw table.

John

With 3/16" alu. you could cut it with a hacksaw and a home made miter box with a stop in no time. A table saw is way over kill.

Either way you gotta build a fixture of some sort.

I like the idea of drilling the hole for the rod on the sled.

These pieces of rod will end up being the "nuts" for a bandura I'm building so it's pretty important that the bottoms are flat and that they are the exact same length. Hacksaw is fine but I expect that the bottom will have to be cleaned up more than on the table saw. I'm hoping I'll just need to clean up the burr using the table saw. Using a hack saw I'll have to make yet another fixture to clean up the bottoms once they're made.

I've attached a lousy picture of what I'm making - the camera moved when I was taking the shot and the instrument I took the picture of is no longer available to me. On this instrument, the nuts are brass but typically they're Al.

_________________
http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com