Crank Pins, Material and Clearance

[FLtenwheeler]

Hi All

I used case hardened 1018 steel on my Allen 10-Wheeler and have had no wear. Now that it is time to work on the Mikado pins I am thing of going with 4140 and hardening after they are machined. I am looking for input. I will need to thread the ends for nuts, so I think pre-hardened would not be useable.

Also what clearance should be used for oil lubrication? For grease lubrication?

Thanks

Tim

[Bill Shields]

Do not make your clearances close or you will bind as the suspension works. A little extra clearance in this area never hurts.

I have always just use 4140 in unhardened form and never had any trouble / wear.

[Harold_V]

I will need to thread the ends for nuts, so I think pre-hardened would not be useable.

Bill addressed the clearance issue but I'd like to comment on the prehardened 4140. Use it! It's not too hard to machine and, in fact, tends to machine with a better finish than annealed material. You can enjoy success with HSS.

Harold

[10 Wheeler Rob]

I used the half hard 4142, it machined and finished up very nice for my 10 Wheeler. No noticeable wear after 3 years of running.

Rob

[LivingLegend]

I'd go with 4140HT, which is pre-hardened to Rc32. 4140HT machines nicely and threading the pins shouldn't be any problem.

If you want to go really exotic, you can use 52100 heat treated and ground.... But 4140HT will more than do the job.

LL

[FLtenwheeler]

I would like to thank everyone for the input. It will be a great help.

Tim