Drilling and tapping M1917 receiver

[Bruce_in_Oz]

i drill all the way through the locking lug weighs, drill all the way through,, why? ever break off a tap in a blind hole?

YES!

Use LOTSA GOOD lube, small "bites" and frequent "backing-out" and swarf removal, and one other hint:

Use best-quality SHARP, CARBON steel taps, not the new-fangled alloy-steel ones.

Why?

Even if you snap off a carbon steel one, and the broken off tip is fully in the blind hole, you can either try the appropriate tiny tap removers, or gently bash it with a small hard punch and it should shatter and be removable in pieces. (Caveat: Murphy was an optimist!)

Alloy steel ones are a lot less brittle, (but they still break) and if you start pounding on them, will distort and embed themselves deeper into the cut thread. Once that happens you only have a few choices.

1. Find your local EDM operator and have it "eaten out"; probably not a cheap exercise, but causes minimal damage.

2. Find someone who has Stellite, or better, diamond tipped tooling and try drilling it out.

Good Luck!

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[rcathey]

1. Find your local EDM operator and have it "eaten out"; probably not a cheap exercise, but causes minimal damage.

Good tip to keep in your back pocket! I work with specialty tooling that costs many times more than the average sporterized 1917. Broke a tap off in a $1,500 one once. It’s good to know a good EDM guy