belt slipping on KMG

D

Dana Hackney

Joined
Nov 1, 2005
Messages
174
Hi folks,

I'm not sure what's going on but I've noticed that, when grinding on the flat platen, my bellts
slip even when I'm not pushing that terribly hard. I've got some pyro-ceramic glass on the platen and even had some of the graphite backing on it. I took off the graphite backing and still have the problem. I make sure I've got the tension set plently tight.

Could it be that I've worn out the little spring that's attached to the tensioning arm, or could it be that that the pyro-ceramic puts the belt too far past the rollers? I'm clueless as to where to look.

Many thanks,
Dana
 
Dana,

Check to see if it is: the drive belt ...or the abrasive belt, that is slipping. I think it might be the drive belt....if the abrasive belt slips..it ussually comes off.

Press into the machine so that it slips and the abrasive belt stalls. Quickly look to see if the drive shaft is turning while the machine is stalled.

It is unlikely that the spring is weak....check to make sure that the tension arm pivots freely...it might be binding with grit in it....such that it is not pulling the belt tight. Clean this joint...and reassemble with a drop of oil.

These are just the first thoughts that came to mind. I'll be watching this thread.

-Rob
 
I find that when I push on the belt it wants to slide in the direction of pressure.

I know I've had the tensioning arm stick before so I'll give it some oil tonight.

If the drive belt is, indeed, slipping is it advisable to use some belt dressing or should I
just go buy a new one? I cannot recall what size it is so I'll go look on your website.

Thanks again Rob,
Dana
 
I had the same problem. It was the drive belt. I simply had to reposition my motor so that the drive belt was a bit tighter. I already had holes drilled, so I just shimmed it up with a thin piece of plywood. End of problem.

For what its worth, I cant get the three pulleys to work the way I would like. If the motor is positioned so that I can swap them belt among the three grooves freely, it is also loose enough to slip as you mentioned. When I place the motor in a position so that the belt is tight, I have a very hard time switching among the grooves. Any advice?

Thanks,

John
 
This has to be the problem. I'll have to spend some time drilling some extra holes in the
mounting plate. I've got my motor (2HP Baldor) on a hinge and a hole through the base plate on which the assembly is mounted. On the opposite side of the motor I have a heavy wire attached to the motor's foot. The wire runs through the table and I have about 15lbs of weights for tension hung off of it.

Thanks again guys,
Dana
 
made sure the drive pulleys weren't slipping (they were not). I stalled the belt
and could see that the drive wheel on the KMG was spinning. I took a closer look
and the aluminum wheel was shiney smooth, so I took a piece of sandpaper and took the shine off the surface of the wheel. It seemed to do better but I'm still not quite sure
if this is the real problem. I don't want to do something stupid and damage the
machine.

All of the belts I've been using lately are used so the backings are a little worn and the insides of the belts are somewhat smooth/shiney. I would not suspect that using used belts should cause the slipping but,.....

Should I be applying as much force as possible on the tensioning arm when I install belts?
Does this cause undue pressure and damage the machine?

Thanks guys,
Dana
 
I just don't think your using it right. This is how I do mine when I change from different tooling. I pull the tension bar all the way down and hold it there while pulling out the tooling arm till the belt stops the arm and then tighten the lock. I'll turn it on and adjust with the tracking screw.
 
I follow the exact same procedure when putting on a new belt. It's only been lately that I've seen this problem.

Thanks Richard,
Dana
 
Hmmm... Dana I'm at a lose here...

I can't duplicate the problem here in the shop. For me....the motor slows down and stalls....no belt slipping with a normal amount for tension. "Normal tension" is hard to describe since it is subjective but you should be able to figure it out....since you already have a generous amount of experience with the grinder.

Do you think the belts might be slippery with graphite...? Clean the machine to remove any residue...and try a new belt....?

Sorry...I'm just guessing...I don't know the solution....
 
The belts I have been using had been used when I had a graphite backing
attached to the platen (I've also a some pyro-ceramic on the platen).

I will try a brand new belt after I wipe down all the pulleys and wheels.

I'm guessing your guess is the source of the problem.

I'll let you know.

Thanks a lot, Rob,
Dana
 
I'm sure that you must be able to get some of the same 'stuff' we have in the UK, used by 'fitters' and available from such places as hydraulic pipe suppliers.... well all it is a anti-slip spray (spray onto belt and it removes the shiny surface and keeps it from slipping), by using this stuff you dont even need to overtension the motor drive, thus avoiding bearing wear etc....
 
Have you adjusted the pivots at all on your machine? I found that after taking mine apart to paint it, upon re-assembly I very slightly over tightened teh lock nut on the spring arm pivot and it would bind a little causung too little pressure on the belt. I just backed the pivot nut off a half turn and everything was fine. That's probably why Rob uses Nylock type lock nuts on those pivots. The tolerances are pretty tight on both the arm pivot, and the tracking mechanism and too much torque on either will cause binding. I can't imagine any graphite in a friction drive system would help either, nor would you want to breathe it!
 
I'll take a look at the pivot arm lock nut as well. This is another
good possibility as I did tighten it up a bit a while back.

Thanks also for the tip on the anti-slip stuff Brit. I'll look into
trying some of that out.

Best regards,
Dana
 
You also may want to consider putting a single strip of electrical tape on your drive wheel. Put it around the center. I had a few minor tracking problems at first and doing so 100% fixed the problem, and may force the belt to stay centered. Can you see the belt wandering on the back drive wheel as well, or does it just migrate on the platen? Does it migrate on a contact wheel under pressure as well?
 
Dull belts will do that.....try a freash sharp belt and back of on the pressure you are putting on the blade......
 
for the additional tips and advice.

The tape trick sounds like a good thing to do regardless. I'll have to check to see whether or not the belt wanders on the drive wheel. I was only paying attention to the belt moving off the
platen.

Thanks much guys!
Dana
 
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