What is being claimed for Mach is that it can do rigid tapping IF the spindle is a controlled C axis rather than just a free running spindle. Under these conditions any CNC control that can do two axis coordinated motion can do rigid tapping. Rather a special case as most machines owned by hobbyists and small shops do not have the capability to run the spindle as a controlled axis.
Tapping using a "compression/extension" holder is possible with most machines even without a controlled spindle. It can be a guessing game with stopping the spindle and accounting for inertia, but lots of folks do it. Steve Stallings > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Sam Sokolik > Sent: Wednesday, October 03, 2007 11:03 AM > To: [EMAIL PROTECTED]; Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Desktop CNC Website Information > > > ok - that is not rigid tapping. In rigid tapping - the tap holder is > rigid - no movement in or out. Emc2 tracks the spindle thru the reversal > and back out using a quadrature encoder with index. At all times > the axis > motion is synced with the spindle. > > http://youtube.com/watch?v=JCEwlfJj__A > > that is a tap held in a Jacobs chuck. (no movement) (and yes - > it was done > in metal also :)) We wish we would have recorded that. You can > read about > it here. > http://www.linuxcnc.org/docs/devel/html/gcode/main/index.html#SECT > ION00340000000000000000 > > Sam > > ----- Original Message ----- > From: "Steve Blackmore" <[EMAIL PROTECTED]> > To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> > Sent: Wednesday, October 03, 2007 2:29 AM > Subject: Re: [Emc-users] Desktop CNC Website Information > > > > On Tue, 02 Oct 2007 20:57:37 -0500, you wrote: > > > >>sam sokolik wrote: > >>> really - I was in on a converstion with art at the > cncworkshop - he had > >>> said > >>> he thought mach would probably never do rigid tapping. > > > > He's known to be wrong on occasion <G>. > > > >>> Could you explain? I could see if you had the spindle setup > as a rotory > >>> axis... but other than that I have no clue. Maybe some external > >>> hardware - > >>> doing it outside of mach? (I am not a mach person). > > > > The spindle is set up as a spindle. The feed/speed is at the thread > > pitch for rigid, at 95% pitch for an expanding nose tapping head. > > > >>Yes, if they use one pulse per rev in a single-channel sensor, > >>then Mach can't know which way the spindle is turning. > > > > It knows because you told it either M3 or M4 - everything doesn't "have" > > to be complicated. > > > >>You have > >>to have a quadrature encoder with index to do it properly. And, > >>you need much more than one pulse per rev so the Z axis can keep > >>up with the rapid speed change when the spindle reverses. > > > > Define "properly" - I've done it, and somebody else wrote recently they > > have been rigid tapping regularly with Mach. Nobody told them they > > couldn't - so they did. > > > > I tap on a regular basis but not strictly rigid fashion - I use an > > extending nose tapper "Tapmatic SM4". It works fine. Through hole is > > easier than blind hole, but spiral point taps are pretty much essential. > > But I also remember all those people, including Art, who told me years > > ago that you couldn't do lathe threading with only one pulse per rev ;) > > > > > > Steve Blackmore > > -- > > > > > ------------------------------------------------------------------------- > > This SF.net email is sponsored by: Microsoft > > Defy all challenges. Microsoft(R) Visual Studio 2005. > > 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 > > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Splunk Inc. > Still grepping through log files to find problems? Stop. > Now Search log events and configuration files using AJAX and a browser. > Download your FREE copy of Splunk now >> http://get.splunk.com/ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
