Help with flat belt tracking

[michiganbuck]

Just for a test, I wonder if one might put a strip on tape at the midsection of a flat pully to see if that makes it go to that center. perhaps a 1/8" wide strip of duct tape for 5 wraps might do for a test.

 

[atomarc]

That little trick will work..I've done it, but if the driver and driven pulleys are wonky to each other the belt will still miss-track when run backwards.

Stuart

 

[RCPDesigns]

I was pretty confident it was the motor not aligned with spindle but it looked correct. I loosened the mounting bolts and twisted the motor (with respect to spindle) and no change.

I think the tape strip in the middle of the pulley is the next step. Hopefully that will be it. The grinding wheels I ordered, along with the suggested spindle oil, arrived today so I'd love to be able to test things out tomorrow or this weekend.

 

[JST]

If both pulleys are crowned, the system will accept a fair amount of misalignment and still work. That seems to work better with the rounded crown, vs the straight slope type, which is much easier to do.

 

[Tom A]

A belt that is not straight will move from side to side.

I was also thinking this - Take the belt off, and lay it out flat - If the belt itself is curved instead of straight, that may be your problem. A curved belt, being longer on one edge, for sure could track funny because of it.

 

[michiganbuck]

Be sure to figure out the expected spindle RPM. 7" surface grinder types often are 3450, and cups are what they say on the blotter. All wheels should have a blotter on both sides even if you make them out of cereal box material and stuck with dabs of Elmer's glue. Many diamond wheels can run at 5.500 and some higher.

A guard should be in place and still, you should stand not in the blow-up circle.

For cut-off wheels, it is good to have a weak to lock your spindle to tighten wheels because it is easy to crack one trying to hold it by hand.

Wheel spindle nut and flange nut should be as tight as an average strength guy can pull with a wrench about 6 or 7" long with a hand on the wrench and a hand on the wheel...and the nut turning should tighten towards the tightening..as if starting the spindle will tighten both nuts. I like to have a red-mark at the left-hand side to tell everyone that that end is left-hand.

Tc grinder should run right and left for different kinds of cutters. When you run the wrong way you avoid hogging, and be sure the wheel is tight. (Some times you run the wrong way to grind into the edge for carbide, and some times you wrong way to skim off a burr.

Diamond wheels like 4500 to 6500 SFPM (and higher), but will grind OK at 3000 to 4000 with not hogging, slow speed like this can cause more wear to the wheel but is commonly done.

The labeled wheel RPM is often best, and that maximum speed..

 

[RCPDesigns]

Really great advice in this thread. Many thanks! Can't wait to grind a couple lathe tools.

 

[michiganbuck]

Qt: (Can't wait to grind a couple of lathe tools.)

You can fudge up an angle plate with a long V block at tilt 12* x 30* and so have a decent drill point grinder. Yes, you hand-roll the heal after the Tc grinder after you facet grind the primary cutting edge..

Oh: and the other end thread of the spindle is noted for catching one's shirt and winding up so tight to cause injury, Good to design some kind of smooth ball or something to have on/cover that end for safety. Or have a guard in place so you can't get that close with your shirt.

 

[RCPDesigns]

Qt: (Can't wait to grind a couple of lathe tools.)

You can fudge up an angle plate with a long V block at tilt 12* x 30* and so have a decent drill point grinder. Yes, you hand-roll the heal after the Tc grinder after you facet grind the primary cutting edge..

Oh: and the other end thread of the spindle is noted for catching one's shirt and winding up so tight to cause injury, Good to design some kind of smooth ball or something to have on/cover that end for safety. Or have a guard in place so you can't get that close with your shirt.

Dang... hadn't even thought about the other end trying to grind me up, thanks for the tip!

Added some duct tape and she runs right down the middle... just perfect!

I'll be taking the spindle back apart as planned to add the new felt seals. I'll add a crown to the pulley while I have it apart.

Many thanks to everyone here, such a wonderful resource of information that was gained from experience.

 

[michiganbuck]

I like a slight heat rise from a plane-bearing spindle. You might consider going up oil weight until you feel a little heat gain with an hour's running. I jog-start all grinding spindles, up to about half speed, let down then fire up.

Spindle oil of 10-15 and 20 are common. 10 and 20 are common for high-speed spindles
8 weight can be had but is hard to find.
The spindle should not get too hot to place your hand there, just a little warm is good. one end may get hotter than the other, go by the hotter end.

QT: (Added some duct tape and she runs right down the middle... just perfect!) *but that is just a test because it may wear loose and get tangled...so sucking in your lathe, mill, drill press and pet dog into the works...and possibly making you spill your beer.