I use a galvinized steel pipe about 2" in diameter and I have put steel shot into it. I then roll that over my forearm on all surfaces including the radius side which is very tender at first, as well as the underside of the forearm as well as the top.

I started out with small number of reps, lots of jow before and after along with massage. Add this to a Three Star routine and you will be able to withstand and give out great punishment with your lower arms strikes/blocks. I added a rep per week to slowly condition the bones to take the abuse.

Peace,

Dale