I used 1 1/4" hexagon stock, then used 5/8" heim joints tightened up to the stock for bearings, the hex gives a nice place to weld the bolt to. By the way, I have the spindle jig and axle jig that I may no longer use if anyone is intrested in it? great scrub angle, works with 8" wide front rims, the Zero Tolerance used them for many wins?