Can anyone tell me why the through holes in the the idler arm are chamfered on the side that mounts against the frame?

What length bolt and thread pitch, Im thinking 3/8-16 x 1.250 w/ a lock nut?

Thanks Rich

The holes are punched not drilled so they wind up tapered, especially in thick material.

I'm pretty sure the bolts are 3/8" they are fine thread for sure, and use nylock or stover (crimp lock) nuts.
David

Thanks David,

I will look for some 3/8-24 hardware grade 8.