Thanks for the info AmishWarlord, the actual tracks he used on our test stands are the Incra T Tracks.
http://woodworker.com/search.asp?sea...FQmMtgodVV_l3g
They use regular 1/4x20 bolts and the heads fit without machining. But I think he might have machined the bolt heads to use larger bolts in the test stand.
All this time and I totally had forgotten about the Mitre channels and Tee Tracks.