Been looking at Stainless steel for bearing shaft. I usually buy 303 stainless bright bar for bearings shafts, and was looking for what would be better.
There’s a link to the comparison of what the different numbers mean.
But here’s a summary of the highlights and I’d love to have the input of an actual mechanical engineer on my assumptions. Two things I can see that would affect the steel to use is its tensile strength which I would guess relates to its reluctance to deformation ( IE how likely it is to be straight) and hardness measured in Rockwell hardness or Brinell or Vickers.
From what I understand you want bearings to be over Rockwell B100 (converts to a C22.8) for bearings.
303 stainless is B83 Tensile strength 89900
304 stainless is B70 Tensile strength 73200
316 stainless is B91 Tensile strength 89900
321 stainless is B80 Tensile strength 89900
347 stainless is B85 Tensile strength 95000
The link has more of them but by looking at it you’d initially think bigger numbers are better but its not so. 303 seems like a good mix of hardness and tensile strength 304 is much worse in both 316 is harder ( which is why its considered good for marine application. but all of them fall short of the B100 spec you’d like.
For than you’d like 4340 (chromoly) Normalized Alloy Steel.
It’s B100 and Tensile Strength is 186000 which is double what you get from 303.
I’m going shopping for some later today and will see how that translates to price. Something tells me if I can find it it will be double the price as well ( if I’m lucky)
So if I can afford it 4340 would be good, then 316or 347 should be better than 303 Ive been using otherwise I’ll just stick to 303. Atleast I know that 304 or 321 should be avoided.
https://www.onlinemetals.com/productguides/stainlessguide.cfm
the trick is making it simply appear in the workshop and hope no one notices.