My wanted a touch-pad for her recipes in the kitchen - so I got her one for Christmas. Now she is looking for a holder that will store the pad up under the upper cabinets and pivot down and out for her to read. The only articulating holder that I found was for an I-pad and hers is not the same size. I am thinking of a bracket mounted to the underside of the upper cabinet with a simple pivot, a pair of links that are saw cut for the touch-pad to slip into. I am thinking of making the links out of annealed 304 SS. Do I need to be concerned about work hardening from sawing? I have very little experience working w/ SS.
Slow the surface speed. There's no reason why you can't saw 304 stainless so long as you have two or more teeth in contact with the cut at all times. For thin material, shoot for a 32 pitch blade. Hard to find, but it will do the job.
If you want to see a discussion of bandsawing 304 - 316 stainless, I wrote an article about it last month that will at least explain what's going on, and what bandsaw blade makers do to overcome it:
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It's not easy with small bandsaws to get enough pressure on the cut. Most people try to use a fine-pitch blade, and that just work-hardens the material.
If you're hacksawing by hand, keep up the pressure, don't let the blade skate over the work, and use the coarsest-tooth blade you can get away with.
303 is easier to saw. Just don't use it for outdoors projects.
hard to find? I've never seen or heard of it for large blades. I've got 32 pitch in 1/4 in wide but no way could you put enough pressure for stainless. Where would you go for a fine pitch 3/4" by 10' blade?
Ed, I've got close to a 1000 sq ft of 304 in thickness from 0.060 to
0.250. Is there a Starret VTF blade for this? I have a roll in bandsaw and can put a fair bit of pressure on the blade.
I have cut some of the thicker stuff with a 10-14 bimetal blade. But it had better be a valuable project cause the blade won't last very long. Mostly, I just get out the plasma cutter or Modern brand gobbler.
Or speed it way up. Friction sawing SS works exceptionally well. The cut thickness is limited by blade speed. I can do 11ga on my older DoAll, but it maxes out at 1500FPM. I used to have a 36" Crescent that I set up to run at around 6000FPM. It made quick work of 3/8", slowed down for 1/2", and would cut 3/4" in a pinch. The DoAll Zephyrs are purpose-built for friction sawing and run up to 15000FPM.
A dull 10T carbon blade works fine, but will fail pretty quickly from fatigue. Factory welded friction blades run much longer before they break. Make sure to have good guards, and pay attention to the tick-tick-tick that signals the blade is about to let go.
-- Good ideas alter the power balance in relationships, that is why good ideas are always initially resisted. Good ideas come with a heavy burden. Which is why so few people have them. So few people can handle it. -- Hugh Macleod
Ya' got me, Karl. I think the VTH is primarily for barstock and thick sections.
You can take a look at Starrett's selection guides and see what they recommend. They're also very good on the phone. Here's their application-based blade selection info:
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Well, I guess you read my article and you see why regular bimetal blades have a tough go in austenitic stainless. They're probably the most commonly used baldes, however, especially if you don't have power feed. They'll do the job but, as you say, they don't last very long.
Thin stainless is a bugger to bandsaw. If you learn something from Starrett or anywhere else, I'll bet a lot of folks here would be interested.
Ned Simmons fired this volley in news: snipped-for-privacy@4ax.com:
nah... start with a sharp blade, and increase the down pressure.
There's nothing about 304SS in the annealed state that makes it hard to cut, except this: If the blade "skates" (even a tiny bit), it work- hardens the surface of the 304 to WAY beyond what a carbon blade can handle.
Start in a fresh spot - never, EVER try to re-cut in a kerf that failed - and keep enough down-pressure on the blade so that every tooth cuts the whole width of the work.
And _that_ means you may have to go to a coarser blade, because if a gullet fills up with chips, then it lifts off the work and skates. The tooth pattern must be coarse enough to handle the entire chip generated over the width of the cut.
There's benefit in a higher surface speed, because it makes each tooth pass through the cut faster, thus taking off less metal per "stroke".
It's the same thing drilling the stuff. Strong, continuous down- pressure, with fairly low surface speed for drilling by hand.
If you ever have to retract to clear chips, you must transition from full-pressure drilling to retracting in one quick reversal, so the cutting edges never, ever skate (idle is what the metal men call it) in the hole. For the same reason as when sawing, you should clear chips frequently to avoid the flutes' clogging and causing the chips to rub in the hole.
Direct to the mfgrs? Or ask a tool shop to find one for you, at the risk of paying a hefty premium to them for the search.
-- Good ideas alter the power balance in relationships, that is why good ideas are always initially resisted. Good ideas come with a heavy burden. Which is why so few people have them. So few people can handle it. -- Hugh Macleod
Speed that sucker up... I worked at an ultra high vac company that makes time of flight instruments, all in 304ss. They took a rather unimpressive Craftsman band saw and upped the blade speed into the lower reaches of friction sawing territory. It would saw up to 1/8" with ease,
3/16 would slowly bog the motor requiring cutting in short advances. Used 1/4" woodworking blades. Oh, it's pretty noisy...
Not often I learn somthing new. Sounds interesting. I'll try a dull blade, not much investment for that. Where would you order a regular friction blade?
I bought Milford brand blades from a travelling tool rep. We tried having them welded by a local saw shop, but the factory welds held up much better. The blades for that 36" saw were almost 20', and because of the blade length and large wheel radius, the saw teeth were usually just bumps by the time the blade let go. I never seem to run out of dull blades for my 16" DoAll, so I just use them instead of buying real friction blades.
Here's a supplier and some more info. Unless you have a very big saw with lots of HP I wouldn't bother with anything wider than 1/2" blades.
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The chips coming off my 36" saw at 6000FPM were hot, with a just a few dull red sparks. More a case of softening the material in the kerf and dragging it out rather than burning it. The saw in the pic on that page must be running much faster.
Never had a problem with igniting debris in or around the saw, but it'd be safest to remove any flammable dust before friction sawing.
I was saber-sawing an opening in a stainless steel industrial oven door and didn't notice immediately when the teeth stripped off and the blade began cutting by friction. The blade kept cutting at about the same speed, without throwing hot sparks. When the blade wore down unevenly I turned it backwards and continued.
Yup, when everything is working right, you apply pressure to the cut and there's a slight delay while the kerf heats up. Once there's some movement, it doesn't take much force to keep the cut going. If too much force is required it means the blade speed isn't high enough. At
1500FPM my DoAll works, but is less than ideal, on 1/8" SS.
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