Whats the thread size for the runner bolts on a TPI setup? I stripped one of the torx last night, and plan on replacing them all with allen head bolts.

 

The bolts are M8x1.25.

If you use hex-socket ("Allen" is a proprietary brand name of Holo-Krome) try to get cheese-head cap screws. Don't laugh, becuase that's what they're called. They are a lower profile, broader head cap screw, just like the originals.

A standard socket cap screw does not have enough bearing area under the sholder. If you have to use regular socket cap screws, you'll also have to get hardened washers to distribute the load so you don't stress crack any of the castings. 5/16" hardened washers will work fine if you cannot find 8mm washers. You'll also have to consider the slight length differential caused by the washers, and the extra head height, so trying to find the cheese-heads is worth your time. If you have a Service Supply or Fastenal distributor in your area, give them a call.

 

Are cheese head screws the same as button head screws?