jackieschmidt
Gold $$ Contributor
Al, I agree that the blind hole is solely for aesthetics. But if you are set on it, first drill your hole with the #3 drill with the point at the desired depth, being as close close to break through as you feel comfortable,
Then, at the Bench Grinder, square the point of the drill, (grind it flat). then re establish the cutting edges on the drill. This will allow you to establish a flat bottom in the hole,
Then chuck your tap up in the collet, and start it dead straight. If you are worried about tapping 416 stainless, it drills and taps quite easily due to it’s free machining qualities.
I have added a 3d screw to several of my bolt ins for the same reason you described. My Bat M, the one I converted to a screw in shroud where I had to move the trigger hanger back, I use three bolts, discarding the rear tang. Two are 1/4 28, one 10 32.
Al, for an old tip, use a carbon steel tap. For one or two holes, it will cut just like HSS, but in the case you do break it, you can take a small torch, heat it red, let it cool, and drill it out as, unlike HSS, it will anneal.
Remember, the two biggest causes of tap breakage are too small of a tap drill, and the tap going in crooked.
Then, at the Bench Grinder, square the point of the drill, (grind it flat). then re establish the cutting edges on the drill. This will allow you to establish a flat bottom in the hole,
Then chuck your tap up in the collet, and start it dead straight. If you are worried about tapping 416 stainless, it drills and taps quite easily due to it’s free machining qualities.
I have added a 3d screw to several of my bolt ins for the same reason you described. My Bat M, the one I converted to a screw in shroud where I had to move the trigger hanger back, I use three bolts, discarding the rear tang. Two are 1/4 28, one 10 32.
Al, for an old tip, use a carbon steel tap. For one or two holes, it will cut just like HSS, but in the case you do break it, you can take a small torch, heat it red, let it cool, and drill it out as, unlike HSS, it will anneal.
Remember, the two biggest causes of tap breakage are too small of a tap drill, and the tap going in crooked.
Last edited:
I've edited my original post. -Al
-Al
