On Tuesday 31 May 2016 10:32:26 andy pugh wrote: > On 31 May 2016 at 14:47, Gene Heskett <ghesk...@shentel.net> wrote: > > 2. So this bore job will have to be done by the mill using a g2 or > > g3 cycle. And a fresh 1/4" mill. And I'll have to study up on > > shrink fits. I want this one tight enough it will take a hacksaw > > slot > > I was going to suggest keyless bushings: > http://www.mcmaster.com/#keyless-bushings/=12nf3l7 > But at that price, perhaps not. > Yes, pricey to be sure. I'd love to have the flush mount on the right side of the page, but they don't make one small enough. But it does give me an idea because theres nothing to prevent me from using smaller screws. There's nothing preventing me from boring it tapered and making another, smaller than I did for the z motors gear, miniature taperlock hub, perhaps with a dozen holes alternating threaded and clearance, doubling the three bolts normally used for a taperlock to 6 smaller bolts. A 3mm.5 times 6 should be able to get a non-slip grip on a half inch shaft. I ordered 2 pulleys, and I can bore the first one to fit the existing shaft, and use it to bore the 2nd pulley and make the hub. I do have room in front of it, enough to clear the screws heads if the flange is thin enough. And the hub length is such that a teeny taperlock wouldn't reach all the way thru it, so I could make the tapered insert shorter. I'd have about 1/3" inch of alu around it, which should be sufficient to hold the tapers wedgeing forces and give me plenty of room for 6 of the 3mm.5 cap screws. I've a whole box of them 12mm long.
But I just got a swag measurment on the C-C distance, and its about .2" longer than I got using the calculator, so I need to go find that page again and double-check the figures. I have enough room to move a bit, but I have to keep the shaft level too. Found it, and counted teeth on the upper pulley & got 30, I was thinking 32, so the belts I ordered will be a cog short, but I believe I can move the countershaft that much. I need to find a hex head metric bolt to use for a spacing jackscrew, whats in there now is a round head phillips and the only way to tighten it is grab the edge of the head with a suture clamp. And since I destroyed the belt, its obvious it was not tight enough if it allowed the cogs to climb out of the teeth in the pulley. Perhaps I could remove it and make flats to grab with a 5mm metric wrench. TBD obviously. > They are very good, though. At $55 & change for either of the two I could use, they'd better be. But I believe I can make the taperlock myself, I already have 2 I made in the Z drive, a 40 tooth on the motor, and an 80 tooth on the end of the ball screw that mates with the 40 on the motor. And that motor on about 37 volts can move the Z at 70+ IPM with quite a bit of drag from the gibs. I was amazed, a nearly identical 425 oz/in motor direct drives a similar screw in the G0704, and tops out at about 70 IPM in mid travel with a 42 volt psu. Set for a G0 of about 48 because thats all it can muster at the end of the tables travel, which obviously wedges the gibs a bit when its 40 lbs out of balance. Poking around in the detrius of the shop, I came across a bag I'd only faintly remembered, with 2 brand new and one nearly so of the 1.5x70 OEM chinese belts in it. I figured its about the right length, but I didn't feel like coaxing the alu pulleys off and putting the OEM plastic stuff back on, so I wrapped it around the new XL pulley and couldn't make it slip a cog. Humm, so I rolled it on, then jacked up the tension. And taking light cuts, running at about 150 revs, the belt was being slapped around quite aq bit becaquse of the cog spacing miss-match but it wasn't slipping. 4 hours later it must be wearing in as its not being slapped around near as much, but I paused it as it was not quite done since I was only cutting .1mm off the radius per pass, and it needed to cool as the whole housing, heated by radiant heat from the upper pulley was above 125F but the rest of the headstock was below 105F. And this was at nominally 150 rpm, making cast iron dust like fine playsand. Because normally thats all covered up, I wonder if even the correct XL belt was heating that badly at 5x or 7x the motor speed. Could be part of the failure mechanism of the kevlar/neoprene belt, and I'll sure check it out when the bigger pulley's and the 140XL037 belts arrive. Thanks Andy. 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
