On Wed, 16 Feb 2011 23:05:21 +0200, you wrote: >On 16 February 2011 19:28, Igor Chudov <ichu...@gmail.com> wrote: > >> Which brings up a question, can one tap with a plug tap first, on a CNC mill >> that is equipped for rigid tapping? > >Probably, but one flute of one thread cuts the whole thread. With a >taper tap the work is shared over several teeth and flutes. > >Machine taps are somewhere in the middle, not needing the >self-aligning taper of a hand tap, but not threading right to the >bottom like a plug tap either.
There are predominantly two types of machine taps. For through holes there are spiral point taps, very much like a conventional hand "second" tap. For blind holes use spiral flute taps. They don't thread all the way to the bottom, but not far off - certainly better than some of the hand plug taps I have with pointed ends! Here's a link with a picture of both types on one page http://www.cutweltools.co.uk/files/ww/BSP%20Spiral%20Flute%20&%20Spiral%20Point.pdf As for using hand plug taps for machine tapping - I wouldn't, they have a nasty habit of snapping off in the hole! My spark eroder has earned some good money because of that - it cost's far more than the price of a machine tap to remove a broken one from a blind hole ;) Steve Blackmore -- ------------------------------------------------------------------------------ The ultimate all-in-one performance toolkit: Intel(R) Parallel Studio XE: Pinpoint memory and threading errors before they happen. Find and fix more than 250 security defects in the development cycle. Locate bottlenecks in serial and parallel code that limit performance. http://p.sf.net/sfu/intel-dev2devfeb _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
