Mule drive pin, broken.
 

I had picked up a 1810 with a bad motor for a parts tractor last year. I removed the deck and mule drive and found this pin broken off. Anyone have a opinion what hardness?

Seeing as it is a welded pin, I would guess it is not hardened.
Grind off the stub and knock it out, and weld in a new one, paying attention to making it square to the bracket.

I took a grade 5 bolt modified it with my 1922 South Bend lathe. I left the threads on and will bolt it in place. Then weld and cut to length.

:ThumbsUp:

I would of used my 1918 south bend lathe and used a soft common bolt or piece of cold roll steel that has not been case hardened that will be changed during the welding process.
If you insist on using that bolt, use low hi rod (7018) when welding it. :beerchug:
And skip using the threaded part as it is the weak part of the bolt.:biggrin2:

I cut the heads off of 2 bolts and the threads and used the unthreaded stubs to weld into a mule drive for a wide frame/ cockeyed idler pulley style. They were eaten away to half or less of original thickness.