Hi there - I probably posted a while back regarding my valve recon project. Im Really struggling with this thing - when I chuck the valve in and tighten, and start the motor - the darn valve keeps getting loose (the chuck basically unscrews!) after i start doing grinding (small tiny cuts).. Did i muck something up? It does spin in the opposite direction of the grinding stone.. just no clue why the chuck would undo itself?
I'd say that 2old2fast pretty well nailed it. One of my buddies had one that I used more than he did and those chucks do need some cleaning. The grit from the wheel and the metal from the valve face can get in them. Also the soluble oil that you cool the valve face with when you grind it is as much water as it is oil . Every time I used Jim's grinder I spent as much time cleaning it up and getting it ready to use as I did grinding a set of valves. There should also be a stop that sets the depth the valve goes in the chuck. I'm pretty sure that the valve spins in the opposite directon than the wheel on all valve grinders. If the machine has the attachment that lets you chamfer the valve tip and dress the valve tip it is best to chamfer them and if needed slightly dress the tips before you do the face that way you take away the chance that a damaged tip will cause a slight wobble with the valve. When you go to dress the stone be damned careful and gentle as it is real easy to knock the diamond out of the nib and you just blew between 30 and 70 bucks to get a new one depending on where you get it. I'm not sure what the cost is now but one for a Sioux valve grinder was 35.00 in the late 80's and my students usually killed one a year being a bit careless. Clean up the chuck and go from there.
I didn't think of that one, he may have a valve grinder that was in a truck or equipment shop originally that is designed for larger valve stems.
https://goodson.com/products/bvr-38-black-decker-replacement-collet What I thinking of was different expandable collets like the one shown not available anymore.
As far as the diamond for dressing the stone, I got real good at "fixing" that little rock into the steel holder, when I was at school, & became the go-to-fix-this guy. A lot of heavy fisted hunyuks that couldn't be told how to do something... got fairly decent at dressing the stones, too. Anyways, assuming the diamond isn't lost('bout the size of a small plastic pin head, iirc), I carefully drilled(or use a Dremel moto-tool w/mini-round-ball cutter)the center hole in the holder a bit deeper, chamfered the end 'till it was very close to the hole, & used 2-part epoxy to hold the stone in. I set the depth of the stone to just barely clear the top of the hole, so's to give as little leverage on the stone as possible. It's a very good idea to get an extra, sooner or later, you'll need it. When(if) you find the ripped-out one, just put it back into spare parts area. Repeat as needed... . Oh yea, get real good at taking *very* small cuts on the stones to true them. . Marcus...
Hi all thanks for the replies.. no stop in the unit.. its an expanding collet. I did have the whole thing apart and cleaned it as part of the restoration. As for wiring it backwards i though of that last night, but doesnt a single phase motor only spin one way? the upper motor spins real smooth - the one that holds the valve seems like its laboring and despite putting the armature on the lathe and flattening it with new hi grade brushes.. everything seemed in pretty good shape.. ive been test cutting with marvel mystery oil - I did buy a dresser and did dres the stone, it was pretty close but a little did come off, luckily nothing broke having said that it was chinese and very well secured as short as possible to reduce the stress - even tho i made light cuts. spent more than a day trying to lap valves and muck around for a motor i gotta get going yesterday.. just really frustrating.
fwiw ill try reverse the wiring and see however not sure if that will change the direction. As i understand it yes all valve grinders spin the 2 moving parts in opposite directions- let me have another look today and report back. So simple a job and its taking me all the time i dont have(!)
Most single-phase small motors are reversed by swapping the wires on one or both of the field windings. Swapping the incoming line wiring won't do anything.
Are u saying the wires inside that connect to the brushes and the magnets? there were 2 spade connectors for the brushes, cant recall if there were more - is it possible I connected them incorrectly? Right now the valve spins against the upper stone which is correct, having them spin in the same direction at the contact point is wrong yes?
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