On Sat, 2008-01-19 at 21:11 -0500, John Kasunich wrote: ... snip > Like taking a cut that is heavy enough that the VFD trips on overload, > and the machine keeps driving the no-longer-spinning cutter through the > workpiece. SNAP! > > My Van Norman mill had the feedmotor interlocked to the spindle motor to > avoid exactly that issue (designed in about 1939). When I replaced the > motor starters with VFDs I did the same, and I'm glad I did. That > little machine is very rigid - enough so that it can take a 1-1/2HP cut > that will trip the spindle drive with no audible sign of struggling. > > Last week I was doing a slot in cast iron with a 1/2" endmill. The cut > started 0.3" deep, but due to a slipping collet it wound up 0.7" deep > before the spindle tripped. There was no indication that the mill > minded taking that cut. > > Regards, > > John Kasunich
Well, I now have some more motivation to get something done. I assume this is your machine here: http://jmkasunich.com/vannorman/VN_Home.htm That is a pretty stout looking machine. -- Kirk Wallace (California, USA http://www.wallacecompany.com/machine_shop/ Hardinge HNC lathe, Bridgeport mill conversion, doing XY now, Zubal lathe conversion pending) ------------------------------------------------------------------------- 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
