Red motor push-in stud measurement?

[Harv]

I've been cleaning out and selling off some of the GMH service tools that I have accumulated. In the box of "I bought it but don't know what it is" tools is a short reamer. I suspect it is a rocker stud reamer to suit red motor. When the push-in studs got sloppy, GMH supplied them in both 3-thou and 13-thou oversize. To fit, the appropriate reamer was used to open the hole, the stud lubricated with gear oil then press-fitted in.

The reamer I've got is not labelled, but I figure I can run the vernier over it. Problem is, I can't find the spec for the original, 3-thou or 13-thou over studs. Anyone know what the studs diameters were?

It's probably a redundant process... most of the time now you would tap the boss and fit screw-in studs. It irks me though that I've got a neat tool that I don't know.

Cheers,
Harv

[ardiesse]

Considering that the rocker studs are 3/8" UNF, and judging on the amount of effort it took to remove and replace a bent one, I'd be inclined to say that the diameter of a standard size rocker stud would be 0.3755" - 0.376".

Rob

[Harv]

Any chance that a standard rocker stud is 0.372"? The ream measures as 0.375", so could be the 3-thou over version.

The alternative is that it could be for the 4-banger early Torries. They had reams in 6-thou and 12-thou oversize, though again I don't know the base size. Less likely though... the tools in the batch I bought many years ago had lots of grey and red tools, though not much for the early Toranas.

Cheers,
Harv

[ardiesse]

It's entirely possible that the rocker stud would be 0.372" diameter. The major diameter of the thread is less than the nominal size, so why not?

Rob

[Blacky]

I would assume the threads would be rolled not cut so it stands to reason the O.D. of the thread would be larger than the O.D. of the stud ?