On Saturday 16 May 2015 18:03:51 Greg Bentzinger wrote: > I bought a HF 7x about 2004 to try and use onsite to make and modify a > huge amount of circuit board standoffs. > > Was doing a major retro fit / upgrade on rack mount chassis equipment. > Bottom line fighting the machine ate up all the time savings of not > just driving to the real shop to do it on proper equipment. > > Gene - you are still looking at this like a 7x lathe owner - not a CNC > lathe owner. > > I would strip everything off the left side of the headstock, that > potmetal cover plate, all gears and other gizmos. Make one large > poly-V micro-v or whatever that is mounted directly on the rear of the > spindle tube and another smaller by what ever underdrive ratio you > deem fit to go on the drive motor. If you think you really need it put > 2 pulley sizes on each end.
That is on the back burner right now since I have a fresh head on hand. Turn the motor end for end and make a proper swing mount right off the back edge of the bed so its nice & rigid. This is a fairly fast motor so I'd likely need something in the 5" OD range to fit the 28mm diameter spindle where the change gear is sitting now. Then figure out how the heck to mount the encoder, whose wheel will then need to be even bigger. I'll have to double check the Y range on the mill, it might determine the pulley size. Motor pulley is of course part of the flywheel, and fixed at nominally 1 inch. 7 ribs IIRC. With a 5" on the spindle, 10k revs at the motor would give 2k revs at the spindle. That is a great plenty. Who needs a backgear? I do need to fiddle with my .hal file though, stop is completely off with no damping from the servo amp, but if I take the pwm down to 1 or 2%, it dumps back into the psu, slowing considerably faster and brightening the 7 watt lamp used for powerdown sink considerably. Programming s# changes while the program is running get good response. Clicking on stop, and it coasts. So it needs a 1% drive until the encoder says its nearly stopped. > > I picked up a nice German made 0.55kW 3ph motor for mine on ebay for > $30 shipped. The VFD may set me back $160 as I think I will get a 115V > 1phase input unit so I can take this innertube boat anchor anywhere. I > will use a 2.5:1 under drive and run the motor up to near 6000rpm. So > with this config I will have full bi-directional speed control and > with added breaking resistor the CSS and reversing will be almost > instant. That could be a problem with this motor, the flywheel/fan/pulley is screwed to the armature & might unscrew itself with "interesting results". However I superglued it back on the only time I had it off. > Seriously - go back to the poly-V - they are more than adequate. A > shop I do work for designs blower retrofit kits and there blower flow > test bench has a 15hp motor driving the Eaton blowers with a 3 rib > belt and no slippage. > > My Uncles Okuma MC4VAE Vertical machining center has a 5 rib on its > 7.5-10hp 12,000 rpm spindle, even tapping 5/8-18 it does not slip. > > All the extra shafts, gears and other gizmos sharing the spindle power > are parasitic drag and extra weight adding to spindle inertia which > fights CNC control. I'm too lazy to fight, I strip the resistance and > only keep what is functionally needed. This lathe will never be going > back to a manual config, so I feel no hesitation burning those > bridges. Neither wil this one. I've already burned that bridge and sold it for scrap when I put ball screws in it. ;-) > BTW - Once you decide on a belt spec I found many sellers eager to > provide 1 pc qtys on Amazon at great prices. I'll keep that in mind. Thanks Jon. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ One dashboard for servers and applications across Physical-Virtual-Cloud Widest out-of-the-box monitoring support with 50+ applications Performance metrics, stats and reports that give you Actionable Insights Deep dive visibility with transaction tracing using APM Insight. http://ad.doubleclick.net/ddm/clk/290420510;117567292;y _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
