On Thursday 02 June 2016 09:15:35 John Kasunich wrote: > On Thu, Jun 2, 2016, at 12:34 AM, Gregg Eshelman wrote: > > There's bound to be some roller chain size between that and bicycle > > chain, which would be ideal for your application. > > Unless this is a mighty slow lathe, I don't think chain is the > appropriate drive mechanism. > > 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. > I've never seen this lathe, only tried to parse Gene's written > explanations. So I have no idea what the real limitations are > as far as pulley size, belt width, etc. Basically its such a poor design that I an biting the bullet and buying a bigger one, which I am trying to make a hole for in the detrious on my garage floor right now, and which I need to get tuit. > > A photo or two of the spindle area would help. What are the > real constraints on pulley size and drivetrain configuration? > > Also helpful would be the following: > > Motor rated power (hp or watts, at a particular speed) > Motor rated speed (at which it develops rated HP) > Motor speed range when used with the drive in question > Desired spindle speed range > > From that information, you can use online resources to > determine the proper type and size of belt and the proper > pulleys to design a reliable drivetrain. Once you know what > you need, then you figure out how to make it fit. > > This chart is a good starting point. > http://www.sdp-si.com/D265/HTML/D265T006.html > Given the rated HP and the speed of the faster pulley it > shows you which belt families can handle the power. > > Doing it any other way is bass-ackwards IMHO. > > It sounds like the existing belt is an XL series. According > to the chart, the maximum power for an XL belt is about > 1/2HP at 3450 RPM, about 1/3HP at 1750 RPM. And that > assumes properly chosen belt widths (not 3/8") and pulley > sizes. If you've increased the motor beyond those limits > (or even close to them), there is simply no way it is going > to be reliable. > > Another option instead of timing belts is multi-groove > V-belts (J series). They have the advantage that you can > make your own pulleys (if you have a working lathe). > A spindle drive shouldn't need positive registration, so > you don't really need toothed belts. 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
