Pivot pin steel type

[antithesis]

Let's suppose a guy not unlike myself decided to make his own steel pivot pins( think Benji 392 pump pin. High stress). What would some of you more seasoned veterans choose for material?  I'd like at least a semi stainless variety, provided a stainless could harden properly enough. And also, how far over the final diameter should I allow for polishing?

[subscriber]

Bill,

It would help to know the diameter and length of your pin.

You can browse these dowel pins:
All pins: https://www.mcmaster.com/steel-pins/=23e3570d1871480ea82440d5301d9f1cjzjubozp
4140 pins: https://www.mcmaster.com/steel-pins/=c81fd17c49da4047a77c5cc3a88d82bdjzju14jx

As you can see, a 1/4 pin can hold 10,000 lb.  Listing of increasing surface hardness.  RC 50 probably combines best wear resistance with fracture resistance:
https://www.mcmaster.com/98381a544
https://www.mcmaster.com/98381a547
https://www.mcmaster.com/98381a332

What force does your pin need to hold?  (pressure x piston area) What is your safety factor?

Choose pin no more than 0.001"oversize for polishing.  Polishing down more than that will make the pin effectively barrel shaped (not cylindrical). Oversize pins listed here:
https://www.mcmaster.com/steel-pins/=c81fd17c49da4047a77c5cc3a88d82bdjzju7zd9

Lube the pin and it won't rust.  Stainless not required.

[antithesis]

Bill,

It would help to know the diameter and length of your pin.

You can browse these dowel pins:
All pins: https://www.mcmaster.com/steel-pins/=23e3570d1871480ea82440d5301d9f1cjzjubozp
4140 pins: https://www.mcmaster.com/steel-pins/=c81fd17c49da4047a77c5cc3a88d82bdjzju14jx

As you can see, a 1/4 pin can hold 10,000 lb.  Listing of increasing surface hardness.  RC 50 probably combines best wear resistance with fracture resistance:
https://www.mcmaster.com/98381a544
https://www.mcmaster.com/98381a547
https://www.mcmaster.com/98381a332

What force does your pin need to hold?  (pressure x piston area) What is your safety factor?

Choose pin no more than 0.001"oversize for polishing.  Polishing down more than that will make the pin effectively barrel shaped (not cylindrical). Oversize pins listed here:
https://www.mcmaster.com/steel-pins/=c81fd17c49da4047a77c5cc3a88d82bdjzju7zd9

Lube the pin and it won't rust.  Stainless not required.

I did end up just getting polished dowel pins, its loads better than the original spring steel roll pins. I just get a lil overzealous with the diy sometimes..

It's not the weakest point anyways, Timmy mac1 got the rest covered I'm sure