Swingarm Pivot Bolts--- Machining, Metallurgy

[DohcBikes]

What are those better options then bob? I'm glad to have an experienced opinion. So far you are the only person saying to definitely not use stainless, and it makes me wonder why. I want to use whatever is best for making the bolt, and cost isn't a big factor.

[BOB MARLIN]

Post #11 would be the ultimate (in my opinion).

[El Camexican]

Its marine grade not medical grade.(******)440 stainless is medical grade and can be heat treated to get very hard (scauples are made of this)

Besides marine grade 316 is also called medical grade SS as far as I know. I believe it is used for some plates that get left in and blunt interments. 440 is as you say used for scalpels (as well as high end knives and some hockey skate blades). 300 SS wont stick to a magnet, but 400 SS will. I think, but am not certain that some if not all 400 SS will corrode a little if circumstances are right.

[El Camexican]

I routinely spill Hot McDonalds coffee in my crotch, just to ease the numbness of everyday society.

If that SS axle ever lets go in a set of whoops your crotch conditioning may come in handy when dealing with the impact.

[atc007]

My expertise on metal? I can weld,and I care for way too much of it... I do however think this is a Pretty damn classy thread with replies from guys who have certainly not seen eye to eye in the past,to say the least . Great thread. MHO? I know it won't stop you Dohc lol. But it is a pretty big motza ball hanging out there if one fails. It kills me to say that.. But it is unfortunately the way things are.

[rg97]

300 SS wont stick to a magnet, but 400 SS will. I think, but am not certain that some if not all 400 SS will corrode a little if circumstances are right.

Right. 300 series, like your 304 or 316 will never rust. 400 series can, like El said, if you have the right circumstances. Just what those are exactly escapes me unfortunately. Just know that it can happen.

I'm sorry if I can't be much of help, I do a lot more work with tool steels like a2, d2, CPM, and so on than I do stainless.

If you dont mind me asking, whats the plan of approach on these? I would guess either find rod of "X" steel that is the dia of the oval-shaped (not endcap, the 1/8" or so part that lines up the frame slot) end then lathe down the long part to fit orig. diameter, then thread end and work on oval slot. I wouldnt want to take it on for the same reason that Motorgidd said, that oval part just makes everything harder. But if you have the means to do it, more power to ya. Discontinued parts being reproduced is a good thing for the most part.

[El Camexican]

Right. 300 series, like your 304 or 316 will never rust. 400 series can, like El said, if you have the right circumstances. Just what those are exactly escapes me unfortunately.

Just moisture, or contact with carbon steel as far as I know gets the 400 series SS to rust. My shop work bench is made of 400 series SS (not sure which grade, got it for the cost of scrap steel) and it develops a thin rust stain if I leave a wet rag on it for a day or two, but it wipes right off. I used to have a scalpel in my tool box and I seem to recall it getting a little rusty after banging around with the carbon steel tools.

Shops that make food handling equipment out of 304 SS have to keep carbon steel away from it at all cost as any contact including grinding dust can cause it to rust. and then acidic passivation (I think I got that right) paste is needed to clean and neutralize it (the same paste you use to turn the welds from black to silver). You'll see all SS commercial food equipment delivered with a tough white tape covering it. That tape allows it to be broke, drilled and rolled on steel surfaces. We also used wood table to weld it on. There are also special grinding discs that are made for SS as the discs for carbon steel contain materials that could contaminate it. I think the discs material is called zirconia, but I'm not sure.

I love SS, it polishes well and holds a shine, looks great and is clean to weld. I spent a large part of my early life working with it and when I go home 30 years later there it is at the airport looking just the way it did the day we installed it. I just wouldn't use it for a swing-arm bolt, an axle or to bolt on foot pegs. I have SS bolts in my triple clamps, brake calipers and holding my discs on and it bothers me. I really should rethink those applications...

[muthey]

I as well deal with stainless 304 316 and 416 on a regular basis, however I do use carbide with mine. scrap the 304 idea for sure. 316 is decently harder than 304, and will not rust. 416 is much harder than 316 but it will rust as it has carbon in it. you are planning on putting a stainless rod in a steel tube so you will still have rust issues as the rust will build around the stainless. My personal experience with stainless is this it heats up very quickly under tool pressure, and as such it expands much more than normal steel does. I always rough my parts in to .100 of said size and cool it off with coolant then take 2 passes of .050 to the finish. A great steel I use when making pivot bolts is 1170 stress proof. machines to a nice finish and will flex without breaking. A comparative to that is 1040 tgp heat treated although it heats up and expands fairly quick, which requires cooling. if you are determined to use non rusting steel then I would go with 316ss. check out this pdf www.ssina.com/download_a_file/specifications.pdf

[atc007]

I as well deal with stainless 304 316 and 416 on a regular basis, however I do use carbide with mine. scrap the 304 idea for sure. 316 is decently harder than 304, and will not rust. 416 is much harder than 316 but it will rust as it has carbon in it. you are planning on putting a stainless rod in a steel tube so you will still have rust issues as the rust will build around the stainless. My personal experience with stainless is this it heats up very quickly under tool pressure, and as such it expands much more than normal steel does. I always rough my parts in to .100 of said size and cool it off with coolant then take 2 passes of .050 to the finish. A great steel I use when making pivot bolts is 1170 stress proof. machines to a nice finish and will flex without breaking. A comparative to that is 1040 tgp heat treated although it heats up and expands fairly quick, which requires cooling. if you are determined to use non rusting steel then I would go with 316ss. check out this pdf www.ssina.com/download_a_file/specifications.pdf

Given that.....I really wonder how Billy's stainless pipe is coming along??? Sounds challenging