Cutting thin hard material

"Proctologically Violated©®" wrote in message news:JeEUh.358$ snipped-for-privacy@newsfe12.lga...

Try a lapidary diamond saw, 6" x .032. They are about $15 + S&H on eBay. I use them to trim SS wire brushes. Spin them at 10k+ RPM.

If you already have the band saw you can try friction sawing. To do this select a medium pitch blade, preferable an old one, and install it up side down, i.e., with the teeth points up. Set the speed to the fastest possible and use a push stick as the work is going to get hot.

Push the work into the blade and push hard. Nothing much happens for a bit and then, if your band saw is powerful enough, the blade will start to cut and it cuts faster then any band saw you've ever seen.

What is happening is that the up side down blade can't cut so it just slips. The heat generated will reach the melting point of the material and then the teeth only have to clear the swarf out of the cut.

We used to do it all the time with a 36 inch Doall saw. It didn;t seem to make much difference what kind of metal you cut except that some took a little longer to get started. I have cut 1 inch high Speed steel tool bits this way.

It does generate some pretty sparks also.

Bruce in Bangkok (brucepaigeatgmaildotcom)

"Proctologically Violated©®" wrote in message news:JeEUh.358$ snipped-for-privacy@newsfe12.lga...

snip---

If the saw model in question is capable of high surface speeds, something above 2,000 FPM, use a fine toothed blade that is no longer serviceable and run it at top saw speed. The faster you run the blade, the better. Some friction saws run up to 15,000 FM, but I've accomplished it on a much slower saw, an old DoAll, circa 1956. It's called friction sawing. You can saw a file in half with almost no effort. Place the object against the rapidly moving blade and watch the heat come up and the cut begin. The teeth need not be running in the right direction, nor are they a requirement. I suggested a fine tooth blade only because it will help prevent the thin material from shucking teeth from the blade. You can actually make the cut with the back instead of the teeth and achieve success. It does take more horsepower, however.

Don't know how it will behave on stainless, I've done it only on carbon steels. It may not work at all.

How about a report when you've given it a go?

Wear eye protection.

Harold

Go fast, ugly, and oversize, with an abrasive cutoff saw, or plasma cutter, then clean up to the line you want with an belt sander.

Or a fiberglass reinforced cutoff wheel on your rotozip.

If you use a wetted down block or bar of metal as your backer, there will be somewhere for the heat to migrate to, other than the rest of the blade.

Cheers Trevor Jones

"Proctologically Violated©®" wrote in message news:JeEUh.358$ snipped-for-privacy@newsfe12.lga...

Send out a plate to your local waterjet shop?

I guess one moral to the story is, Never throw *anything* away!!

Intriguing use of shop tools, really getting every last ounce out of yer dollar. Almost as good as getting a 2fer1 from yer local errant HD cashier!!

Interestingly, the DoAll ML series does go to 1500 rpm, whilst the newer (I think) V series only goes to about 475. One might be able to kluge sumpn sumpn with the pulleys to bump up the speed, OR put the saw on VFD. Not sure what the hp is on the ML, will have to contort my body and check. :)

Appreciate the other ideas, Bruce's details. Really fascinating. Man, a water jet would be nice, eh? This friction stuff is sure a whole lot cheaper than carbide grit!

So it seems like you can use an old blade for friction sawing, until the blade pert near disappears!

I just got a VFD, good for 2 hp, so we'll see if I can bump up those fpm.

If it's the same as my ML, it's 3/4 HP. The 1500 FPM is marginal for friction sawing, but I'm able to cut up to 1/8 SS, so you should be able to manage thinner materials pretty well. I used to have a 36" Crescent that ran at about

6500 FPM which cut 1/2" SS readily, and would do 3/4" in a pinch.

Ned Simmons

I don't recall ever giving up on a blade before the weld broke. These days, for occasional use, I just use a dull blade. But back when I had the big saw and was running it every day I'd buy welded-at-the-factory friction blades. They looked like regular 1/2" x 10 TPI blades, but would run much longer before the weld fatigued.

When you heard the tick-tick-tick of an impending weld failure it was time to get your hands off the table. Most of the time the blade would simply fall of the wheels, but if the weld was in just the wrong place when it broke a couple feet of the blade would pile up on the table in neat little zig-zags.

Ned Simmons

cutting them thin is one thing, doing it without affecting the temper is another. For your purposes though, it sounds like temper really isnt too critical. The cheapest, fastest, lowest heat, lowest tech approach is to buy some razor thing cutting disks for a 4" or 5" grinder. These are made by a few different companies and are iron free, they are designed for cutting stainless. They are super thin, so be careful when using them. If you press too hard, they can just disintegreate. used properly though, they are fast and cut through hardened stainless like the proverbial hot knife. They arent cheap to buy compared to standard cutting disks, but for the ammount of cutting i envision you doing, you'll probably get away with it in

2 or 3 disks to do quite a lot of cutting and it will end up cheaper per-cut that almost anything else, as well as being very acurate and giving a nice clean finish. It puts very little heat into the workpiece. we use these at work for most of our stainless cutting, its better than plasma.

Shaun

It's funny you should mention this, because this is what I used to do w/ .015 blue spring steel on a surface grinder. That the mat'l was magnetic helped, of course. The wheel I used was a 7" x 1/32 non-reinforced, 1.25" hole, and it cut nicely--while it lasted. One errant move, and , dozens of pieces of it all over the shop.

It sounds like they are for an angle grinder? Which means they'd proly last forever on a SG. Mfr? And, it sounds like they will cut broad arcs, as well, which would be very useful.

Also, this material is not *that* hard that I can't use a traditional band saw blade, as it turns out. Will certainly shorten the blade life, so I'll just have to find the finest finest pitch out there, and dedicate it to thin material.. Mebbe flood the table with oil, or use mist coolant. AND try that wild friction stuff! These disks sound promising as well. Will be interesting to see what works best, but it might very well be some combination.

Thanks.