On Thursday 02 June 2016 17:18:24 John Kasunich wrote: > On Thu, Jun 2, 2016, at 03:16 PM, Gene Heskett wrote: > > On Thursday 02 June 2016 09:15:35 John Kasunich wrote: > > > It sounds like part of the problem is a spindle pulley that > > > is too small. That hurts twice. First, it reduces the lever > > > arm and requires more belt pull per ft-lb of torque delivered. > > > Second, it reduces the belt wrap and number of teeth engaged, > > > which increases the load per tooth even more. > > > > > > Bigger pulleys help in other ways too. A big spindle pulley > > > provides some flywheel effect which can reduce chatter > > > and relieves the motor/belt of the worst shock loads. > > > > A larger upper pulley that drives the lathes head countershaft is > > not possible as it runs into the rear of the spindle at about 1 more > > cog. > > When I wrote that I was unaware that this lathe had gears inside > the headstock and that the belt was driving the shaft with the > gears rather than driving the spindle directly. > > I think your "bigger better lathe" approach is the right one. But > if for some reason I was stuck with the 7x lathe, I would ignore > the countershaft with its plastic gears and put a nice big pulley > on the back of the main spindle....
I have considered that, John, unforch no one makes a "J" format polygroove pulley big enough to be usefull as 4" seems to be about tops. I already am using the OEM 5 groove that comes on the motor as part of its huge fan/flywheel, which is about a 1" pitch diameter, and running over a 3" pulley that matches and that turns the jackshaft tht carries the pulley that burns up the belt, and if its the plastic OEM pulley, its burned up too. I'de love to use it as the horsepower ratings of that belt setup kick the best of the cogged belts about 3 drainages over. I even started to make a pulley, but can't buy the tooling to do it right anyplace. To do it right, I'd need a 1" thick piece of 7078-T6 about 7" in its narrowest dimension, and some vcmt tooling. And I'd machine a 360 slot plus index encoder slot setup inside the outer rim too. So if this doesn't help enough to suit me, I'll be online looking for some alu to make that pulley with. But I'll have to make it on the bigger lathe as this one swings about 4" smaller than that needs. 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> ------------------------------------------------------------------------------ What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic patterns at an interface-level. Reveals which users, apps, and protocols are consuming the most bandwidth. Provides multi-vendor support for NetFlow, J-Flow, sFlow and other flows. Make informed decisions using capacity planning reports. https://ad.doubleclick.net/ddm/clk/305295220;132659582;e _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
