Slipping Belts

In his first post on the subject the OP mentioned "leather belt problems". My Seneca Falls machine also uses la leather belt, and like many other members I have tried various belt dressings over the years. The original dressing I used came in a tube and was thick and sticky. Unfortunately almost all the labeling was gone so I was unable to order more when I ran out.

After trying everything from soup to nuts I settled on 3M Super 77 Multipurpose spray adhesive. I've been using it (sparingly) for over 10 years on my 1 1/4" leather belt. It does a great job and doesn't seem to affect the belt. I probably use it 3 or 4 times a year. Having said that I don't over tighten the belt to the point the machine will be damaged in a crash. I generally tighten it to the point that I can take a .125" deep cut off 6061 aluminum. This seems to be tight enough that I can take .060 - .080 cuts on 1018 without slipping, but in the event of a crash the belt will still slip.

If the belting is worn or cracked to the point it needs replacement they can be purchased by the foot from McMaster. They also sell several different styles of belt clips and lacings.
 
I solved the slipping belt on my Heavy 10L by replacing it with an automotive serpentine belt, which I had to splice. It works so much better than a leather belt, the motor will stall before the belt slips.
 
Tozguy said:
Just curious Jack, what is the problem with the V belts....noise...slippage...?
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The trouble is trying to make a silk purse out of a sow's ear.

Among the treasures lost in our recent fire was a nice Jet Mill/Drill.

A friend donated an old Power King drill press to the cause and I have been trying to turn it into a mill/drill. He happened to be a cabinet maker so the 3200 RPM motor didn't bother him much but it was pretty useless for metal work.

I replaced the motor with 1/2 HP 1700 RPM my wife found at a garage sale for $1 and it works great but is still too fast for my purposes.

I tried to re-create the pulley arrangement the Jet used and I think I may be missing something but it works well down to about 200 RPM but the belt/s slip when doing stuff like drilling large holes.

The 4 step transfer pulley I bought turns out to be a piece of Chinese junk but I made it work anyway. The slippage problem might be due to the fact that the pulley looks too pretty to have any traction. It has a mirror finish. Sandblasting might fix that but I think the cure really is in the rosin.

I can not increase the belt tension beyond a certain point that causes the motor to rattle and clack and it's just not good practice anyway. Furthermore, the slip is usuall in the other belt and there is even more reason not to stress that one.

So there you have my problem which may have been solved with all the great ideas posted here.

Thanks,

Jack


BELTS5.JPG
 
Get an old small motorcycle engine and carve the crankcase off it, most of them are 6 speed AND keep a couple of the step pulleys then you will have a real frankenmill.
 
jschmidling said:
View attachment 306494
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If you are trying to run it as pictured, those belts are nowhere near tight enough. Because of the small diameter of the pulley, especially the intermediate one, you would be much better with cogged v belts. They will give you a better wrap on small pulleys. Even with that, such a small pulley is going to have a limited ability to keep a belt from slipping.
 
I thought the same as RobertB but thought it might be an optical illusion. Now I've got my reading glasses on Those belts look like they could be the wrong section as well. They come in metric and Imperial and there are subtle differences

Transmission factors have lots of information for download. Here are some to look at.
 

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  • Gates-Belt-ID-Chart.pdf
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  • Bando V-Belt design manual.pdf
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  • Optibelt-technical-manual-v-belt-drives-manual-v-belt-drives-optibelt-vario.pdf
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NortonDommi said:
Now I've got my reading glasses on Those belts look like they could be the wrong section as well.
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Now that I have done the same thing(reading glasses on) you may be on to something there also. The one that you can see the best in the photo, upper intermediate pulley, the belt looks like it is seated far too deep in the groove.
 
Sorry for the misleading photo. I should have mentioned that I just threw it back together to take the pic. The belts were tensioned only enough to show the layout.

As a point of interest, the machine came with a half inch belt and I switched to 3/8" for convenience. I think I have at least ten belts so far. Every time I change something I need a different belt and it has become a joke around here.

Honey.... guess what? I need another belt.

js
 
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