Hi Greg. Yes they are 1/2-13. I had to chase the holes a day ago. definitely 1/2-13. I got some bolts that will work from Paul (triplep) off a 60 3/4 ton. I'm just concerned about the clearance allowing the axle to rotate a little bit. The bolts are .495 and the hole is .530 if I remember right. The cone would center each bolt like wheel bolts do. I don't know how I ended up with two threads but, I'll attach the same photo's I did on the other thread.