Question about working with stainless steel

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Hi All, I am currently making some bicycle cone wrenches and originally thought about using cold-rolled steel because it is tougher and harder to bend than hot-rolled steel. I also decided not to use high-carbon steel for various reasons partly because the purpose doesn't require it. But I did notice my metal supplier has stainless steel 304 available in a flat-bar size needed for the project. It is more expensive but I don't think painting it to keep it from rusting is needed for stainless. (Correct me if I am wrong.) My questions are, is 304 stainless steel as tough as cold-rolled steel? Tougher? Is it more difficult to cut using an abrasive cutting wheel? Below is a drawing of my design(s) and dimensions. Thanks for your opinions.Steve Attached ImagesJunkYard Tools .com
Reply:Can't help you with the properties of SS, but I can help with the cutting portion. You can cut 304SS with a regular abrasive wheel, but you'll eat wheels and it will cut slowly. You can buy cutting discs made for cutting SS. They will help a lot.
Reply:Thanks Catbed, that's exactly what I needed to know.SteveJunkYard Tools .com
Reply:Cutting stainless steel?  A lot depends on what you are using to cut it.  Plasma doesn't care if it's stainless or high-carbon or cold-rolled or what not.  Abrasive or toothed cutters (milling cutter, drill bit, etc)?  Make sure you have the appropriate cutter speed and feed rate and then go through it.  If you diddle around or don't have things set up right (speed and/or feed rate), stainless steel often work hardens and then is a real b%&$ch to get through.Cold-rolled steel often warps all to blazes once it is machined, because of the built-in residual stresses in the material from the cold-rolling process.  Hot-rolled usually doesn't warp as much compared to cold-rolled.Next, some relatively thin flat bar wrenches seem to me to be pretty easy to warp or bend in use if they are -not- made of some hardened steel.  Some easy use or a one or two time use tool might be OK using plain mild or unhardened steel.  Anything with some torque or load on it pretty much either calls for thick sections and/or hardened steel.  IMHO.And some plain old 304 stainless is usually pretty "tough", in the metallurgical sense because "tough" means it is not going to crack easily.  It is really not all that much harder or 'stronger' than some cold-rolled steel, as both will "yield" and permanently bend at about a stress level of 30-50 ksi with the cold-rolled usually having a slightly higher yield strength (31 ksi yield for 304 stainless vs 51 ksi for 1020 cold-rolled).  As a comparison, some O1 oil-hardening tool steel quenched from 800C and tempered at 425C would have a hardness of Rc 50 and a yield stress of 218 ksi.Some A2 air-hardening tool steel quenched and then tempered at 400F has a yield stress of 229 ksi.Some 4340 steel oil quenched from 1570F and then tempered for 4 hours at 450F has a yield stress of 225 ksi.Making a tool?  Use some sort of tool steel or at least some alloy steel IMHO.Oh, and I'd say to round off the handle ends of the wrenches,  Easier on the hands when there is no sharp or pointy wrench corner digging into them.  Also, if you can put a slight fillet in those inside slot corners of the wrenches.  The sharp inside corner is a BIG stress riser and will tend to cause the steel to rip apart right there once you start cranking onto the wrenches.  The best laid schemes ... Gang oft agley ...
Reply:are you planning to make pretty cone wrenches?  they're pretty cheap from your LBS.  I notice you're making it out of 1/8" thick stock.  If i remember right, I think the store bought ones are 3/32"... is that why you want to make them yourself, to make it thicker?  you could braise two of the store bought ones together and it will be plenty beefy.
Reply:Thanks Moonrise and Oxy,Yeah, it's just a "lotta-time-on-my-hands" type of project.  The typical LBS (local bike shop) set of cone wrenches runs well over $50 for a set of 5 "stamped steel" wrenches. I guess stamped steel could also be considered cold-rolled steel. Amazon has them at around $45. The key to cone wrenches is their thin profile. An 1/8-inch thick is a little on the high side for a cone wrench but will work in most cases. That's the thinnest stuff my metal supplier has. I cannot make anything from tool steel partly due to not having the equipment, and also not having the desire really. The purpose doesn't require it either. Most bicycles have tightening ratings measured in inch-pounds, not foot-pounds, as an idea of the requirements. Some notable nut tightening measurements run around 360 inch-pounds (or 30 foot-pounds). And my bicycles are not carbon-fiber frames either. All mine are classic road bikes prior to 1990, chrome-moly steel frames. But I went ahead and bought some stainless steel today and will see how it turns out.  Thanks for the input though.  SteveJunkYard Tools .com
Reply:Here's a photo of my favorite bicycle. It's a 1984 Schwinn Super LeTour in perfect condition, all original. It was built in Chicago before Schwinn started building them in Taiwan. Today's Schwinn's are now built in mainland China though.Steve Attached ImagesLast edited by rookie_steve; 08-02-2010 at 07:32 PM.JunkYard Tools .com
Reply:The bike looks really good for 26 years old Steve!If the stainless doesn't work well for you try, Latrobe Viscount 44 Prehardened Tool Steel (special ASTM H13S). Properties are 165ksi yield, 205ksi tensile, Rc42-46. Can be dry sawed and machined with HS tooling, it is non work hardening (it's plenty tough though). It's the go to stuff for special wrenches, sluggers, sockets etc.I get it from a midwest tool steel house that has no problems selling real small quantities; http://www.fordtoolsteels.com/index.aspx?page=8Matt
Reply:Originally Posted by rookie_steveThanks Moonrise and Oxy,Yeah, it's just a "lotta-time-on-my-hands" type of project.  The typical LBS (local bike shop) set of cone wrenches runs well over $50 for a set of 5 "stamped steel" wrenches. I guess stamped steel could also be considered cold-rolled steel. Amazon has them at around $45. The key to cone wrenches is their thin profile. An 1/8-inch thick is a little on the high side for a cone wrench but will work in most cases. That's the thinnest stuff my metal supplier has. I cannot make anything from tool steel partly due to not having the equipment, and also not having the desire really. The purpose doesn't require it either. Most bicycles have tightening ratings measured in inch-pounds, not foot-pounds, as an idea of the requirements. Some notable nut tightening measurements run around 360 inch-pounds (or 30 foot-pounds). And my bicycles are not carbon-fiber frames either. All mine are classic road bikes prior to 1990, chrome-moly steel frames. But I went ahead and bought some stainless steel today and will see how it turns out.  Thanks for the input though.  Steve
Reply:I'm all for those "too much time in my hands" type projects.  heck, I just spent a few houre making $30 light stands.another thought:  there's quite a few knife makers on this board.  you might be able to keep the cost down by using hot rolled and ask some of the knife makers for help in hardening... if memory serves, you'll need a heat source (coal, rose bud, OA torch...whatever) and some old trasmission oil for quenching.good luck & take a lot pf pix to show us
Reply:Steve,You can get either pre-hardened pieces of some alloys of steel, or you can use something 'simple' like some O1.  Both can usually be gotten in 1/8 inch thicknesses.  For the O1, you pretty much heat it up (pile of coal with a bellows/blower to make it hotter or a propane weed-burner torch maybe with a few pieces of firebrick to hold things, rosebud, etc) until a magnet doesn't stick, then quench in some oil (watch out for the flames and smoke and spattering oil).  Tempering?  You can use the house oven, that's usually 'good enough'.  Crank oven to 450F (most can get to that), wait for it to preheat, then put the hardened quenched pieces in and leave alone for a few hours.  Turn oven off and leave alone.  Come back later after everything is all cooled off (overnight) and you now have some quenched and tempered tools.  Easy.  Mostly.  Oh, cut and shape the O1 while it is still in the soft state or else you will be filing and grinding for a while.  1/8 x 2 inch O1 from Online Metals about $20 for a 36 inch long piece.  There are other small-order metal places all over the Net too.To me, it's just that 'soft' steel is well, soft.    If I go to the trouble to make a tool I usually kind of want it to last.  Sometimes soft steel, or aluminum, or brass is called for.  Sometimes hardened steel is called for.  Your choice.Oh, and the bike?  Old-school down-tube shifters.  But why is the seat so low?        The best laid schemes ... Gang oft agley ...
Reply:Originally Posted by Matt_MaguireThe bike looks really good for 26 years old Steve! . . . I get it from a midwest tool steel house that has no problems selling real small quantities; http://www.fordtoolsteels.com/index.aspx?page=8Matt
Reply:Originally Posted by Oldiron2When I was 13 or so, I made some gun parts using just a hacksaw, a file, and possibly a propane torch to case harden them; I used the little that I had but it served the purpose. I still have a few of those parts! You say you don't have "the desire really' to use tool steel, but there's little difference in working that vs. cold rolled, once you get some. Case hardening mild steel might also be nearly as good, so long as you don't try safe-cracking with the tools!
Reply:I've got both cold rolled steel and stainless steel to try on this go around. There didn't seem to be a lot of difference in drilling, cutting, or grinding between the two metals. The wide piece is 2-inch cold rolled to be a 29mm bottom bracket wrench. The smaller one is a one-inch wide 15mm stainless steel cone wrench. When I get to filing down the desired dimensions using a hand file then maybe I will notice a difference. Steve Attached ImagesJunkYard Tools .com
Reply:The photo below shows a completed 17mm cone wrench that I previously made from cold rolled steel. I painted it to keep it from rusting. It's not exactly pretty but it looks "industrial."  Painting the last one here is why I wanted to check out using stainless steel but so far I really don't see much difference in working with it.Steve Attached ImagesLast edited by rookie_steve; 08-03-2010 at 06:44 PM.JunkYard Tools .com
Reply:Is that 304 stainless, or other grade?  If it was 304, good job drilling it.I used 304 on some exhaust systems and some kind of 300 series stainless (it might have been something other than 304... can't recall exactly what at the moment though) for a thick plate, I think either 1/4" or 3/8", to make a flange out of.  It was real hard to hacksaw, in particular the thick plate.  I recall there were occasions where the teeth would get stripped right off the hacksaw.  Hacksawing was just the pits on it.  Friction cutting (with a radial arm saw and a metal cutoff wheel) worked well on it though.  Drilling (just with a hand drill, not a drill press) was much more difficult than normal steel.  The thick 300 series plate ate HSS drill bits for lunch, but I found I could make a hole and maybe some more with the same bit afterward if the bit was a Cobalt drill bit.  Huge difference in longevity there over HSS.  I have a feeling having the drill press for drilling would have helped a great deal over hand drilling, it didn't seem like you had any problems drilling your (1/8" was it?) stainless plate.  I can't remember really clearly how filing went, but I think it was slow on the 300 series stainlesses.Now other grades of stainless I have used, 409 in particular, cut and worked like butter... as easy as mild steel (maybe even easier!)Some types of stainless can be heat treated, such as 400 series (martensitic stainless) however all 300 series (austenitic stainless) can't be heat treated.