On Tuesday 11 March 2014 12:29:32 John Kasunich did opine: > On Mon, Mar 10, 2014, at 11:09 PM, Gene Heskett wrote: > > Damn John, I just counted it twice more and got 31 both times. > > At a top of the tooth diameter of 1.803, where the heck does that > > leave us/me? > > > > > > The smaller driver pulley, is .976" across the top of the teeth, and > > 17 teeth, .388" between the flanges. So a .375 wide belt will fit, > > as will a 9.5mm wide belt. But a 10mm will be pinched until it > > burns up the flange anyway. > > OK, we have two data points: 17 teeth and 0.976 OD, and 31 teeth with > an OD of 1.803. > > We also have two unknowns, the belt pitch and the distance from the > OD to the pitch line. That should be solvable. Wait a bit while I try > to do math. > > OK, math done. The pitch comes out to 0.1855", which has me mystified, > because I've never heard of such a thing. (I've done a fair bit if > tooth- belt research for different projects.)
I think you have nailed it. > I did some googling for 3/16" pitch belts. I stumbled across a few > similar tales of woe on various forums. Eastern lathes with belts of > approximately 3/16" pitch, and nobody able to find spares. > > http://www.cnczone.com/forums/general-metal-working-machines/112495-timi > ng-belt-available-lathe.html > http://madmodder.net/index.php/topic,5006.msg56077.html?PHPSESSID=tef5o > 88m42hje4vlt64jolptb2#msg56077 > > One person said: > >> I believe that Roman is correct on the 3/16" pitch. This is an old > >> design from the 50's or 60's and was know as an F profile. There > >> were never any standard sizes and molds were just purchased > >> for a specific OE project. The bad news is that very few F profile > >> belts are still available and would not be something that an > >> industrial distributor would be able to get for you. > > Why a fairly modern Chinese lathe would be using a 50 year old > inch belt type is another mystery, although someone in one of > those threads speculated that the Chinese factory either had a > big stock of belts, or had the mandrel that is used to make the > belts. Again, it makes sense, this design had been in the sale papers of the cheap tool peddlers like HF for at least 10 years when I bought this one back in the late 90's off a Speedway truck at the local VFD. > At this point I'm pretty sure it is NOT any modern standard > belt profile. How hard would it be to replace the pulleys? > XL profile is probably the most readily available and cheapest. >From SPI-SC, about $175 a set in metal & what I assume is kevlar belt backing. In XL format. The bores are a hair odd, and it would be the first time they ever broached a 4mm key in a 10mm bore for the top pulley. STD is a 3mm for that bore. And there is not room to make the top one more than 30 thou bigger without dremel work on the bolt bosses that hold that die cast cover in place on the back of the spindle/gear housing. So it can be done, just bring money. OEM stuff can be had for about 10% of that, for a full set, 2 pulleys and the belt. The weather is decent, already 60F & change, so I'll mess with it some more today, and maybe even refit the motor mount. But the tooth miss-match tells me wear will be high under any conditions of enough tension to keep it from walking. Thanks John. Cheers, Gene -- "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> ------------------------------------------------------------------------------ Learn Graph Databases - Download FREE O'Reilly Book "Graph Databases" is the definitive new guide to graph databases and their applications. Written by three acclaimed leaders in the field, this first edition is now available. Download your free book today! http://p.sf.net/sfu/13534_NeoTech _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
