Forming tap to chase threads on Williams Foolproof ?

[Elric]

Well, there was a launch excursion while comparing Contender FP sights. There is an elevation screw hole, where the threads inside look... a bit inconsistent...

Anyways, I'm thinking [now that I -HAVE- to...] that a forming tap would be most likely to reform the damaged section of 2-3 threads in the aluminum base.

Comments?

 

[Missionary]

I have rethreaded holes with standard taps. The "deformed threads" may "reset", or they are going to disappear as the cutter begins working on them. I would give it a try.
On one occasion I used a tri corner file on the lowest thread cutting a "V" notch in it. The notch cut through the "messed up threads" and seemed to work fine afterwords. Motorcycle motors are what get most of my attention in the aluminum issues.
But here your writing about a precision adjuster. As long as that threaded shaft remains in enough good threads it should raise and lower as expected.

 

[KeithB]

I'd try re-forming it before re-cutting it w/a conventional tap. Thread forming taps in small sizes aren't that expensive.

About $20 here: https://www.mscdirect.com/browse/tn?searchterm=thread forming taps&hdrsrh=true&rd=k

 

[smokeywolf]

Wax may work better with the thread former in this instance than a cutting fluid like A-9 or Rapid Tap.

 

[Ian]

Wax may work better with the thread former in this instance than a cutting fluid like A-9 or Rapid Tap.

The blend of ester waxes in beexwax make it just about the best deep-drawing lubricant there is. Moly EP grease or a drop of your favorite high-viscosity case forming lube work well too.