Kirk Wallace wrote: > Is tapping obsolete? > > http://www.emuge.com/carbide_thread/ >
No. ;-) Reasons: 1) Thread milling works best on larger threads. A thread-mill has to have room to orbit inside the hole - not a problem in a large hole, but the smaller you get the more difficult it is. McMaster Carr has some thread mills in their catalog - the smallest they have is #4-40. Regular taps go down to #0-80. 2) Item 1 above implies that you can't thread very deep with thread mills. The small ones (4-40 thru 8-32) in the McMaster catalog can thread about 1-1/2 screw diameters deep, the larger ones can go to 2 diameters. Taps can usually do at least 2-3 diameters with little trouble, and deeper is often possible. 2) Thread mills work _only_ on CNC, and they require a very accurate machine to produce good threads. If you have any backlash, your threaded holes won't be round. Drills and taps produce round holes and threads, even on a drill press. 3) At McMaster Carr, thread mill prices start at $150 and go up to $300. In the same catalog, taps cost between $6 and $50. Some large taps (3/4" and larger) cost more, and for large sizes thread mills might have an advantage. But under a half inch, the tooling cost is heavily stacked in favor of taps. Regards, John Kasunich ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
