Responding to John Thompson (?, top), John Betmanis (lower) wrote:
At 09:18 PM 1/5/07 -0600, John Thompson wrote:
>>In a pinch you can grind a common tapered tap to make a functional >>bottoming tap. I have one I use explicitly for lever bosses.
Or more likely, grind a flat end on a broken one. Done that more times than I can remember. ;) ++++++++++++++++++++++++++ As a tight-fisted, make-do, type of chap, I'd just drill through the bottom, into the downtube, using the drill that's closest to the diameter for threading that size. Then tap it clean with a regular tap. I just really don't like working with small bottoming taps.* I mean, like the stress riser introduced by the drill-and-tap is (or should be) completely surrounded by a "washer" to prevent crack propagation, and we all grease our threads to prevent water movement, eh? I won't tell, though, if you don't.
harvey sachs
mcLean va.