I picked up a few IHMSA rear sights for the T/C Contender. The stock elevator stem has a crude black finish that is not hard. Its already wearing away in the dovetail.
I did some Super High Intensity Tinkering, and found out that you can open the base dovetail and the elevator stem of a Williams FoolProof fits right in.... However, there is a problem, as the IHMSA sight (possibly T/C made investment casting) uses a 6-40 thread, and the Williams FP uses a 6-48 thread. Result- the elevator screw makes about three turns, then everything stacks up.
I picked up some stainless steel hypodermic tubing, .148 OD and .110 ID to thread internally. Drill out the existing thread, then press in the threaded tubing. Waa-laa, correct thread.
Sight base is steel (suprise!) Web thickness around existing internal thread is @.200"
The tubing comes out as .1475 OD on my Starret. The load will be light, just the elevator stem. What should I drill the existing thread out with (diameter) and follow up with a reamer (diameter)?
I dimly remember a drill should be about .005" under the diameter of the reamer.
What should the final diameter be for a press fit?