Derek wrote:
> Question. Why do taps have such long threaded portions? I
> can understand the tapered lead-in section but why the long
> parallel section?
I would guess that it keeps the thread pitch accurate.
If you were tapping with a lot of force, and only one or two threads
were riding the "completed" thread, the danger would be that the thread
pitch decreases as the cutters get ahead a little bit.
With a dozen full-depth threads in the fresh hole, it should help
keep it moving at the correct ratio of turns per inch.
--
Trevor Boicey, P. Eng.
Ottawa, Canada, tboicey@brit.ca
ICQ #17432933 http://www.brit.ca/~tboicey/
Now 10% more grizzled.
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