poly V belts

[AlexO]

I'm thinking to replace the belt on my lathe with a poly v to cut vibrations and noise. Anybody done that ? Does it work ? They seem prone to slipage on cars.

 

[HuFlungDung]

Yup, did that on my vari-speed Clausing. Its nice, and makes no noise compared to the original timing belt that was on it. This is a small 15" lathe, so it doesn't have to transmit oodles of horsepower, however I did machine the new pulleys to create an overdrive effect.

On a lathe it is not so critical if some slippage were to occur. But on a cnc mill retro used for tapping, a person might want a more positive drive like the Eagle PD by Goodyear. This is a herringbone style belt with matching pulleys, and is also superbly quiet, but you cannot make your own pulleys as easily, if at all

 

[AlexO]

Tell me please if the vibrations are gone compared with a normal v belt. I've changed the belt at least 20 times and can't get rid of vibrations.

 

[HuFlungDung]

Are you referring to belt slap, as on the slack side of the drive? It has been my experience that tension can be a critical factor in belt vibration. Too taut or too loose seem to both affect harmonic vibration of V belts.

Also, the fit of the sheaves on the shafts should be verified okay, as a loose fit will contribute to noise and vibration. I suppose you have already checked for runout of the sheaves in all other aspects.

If you work in a cold shop, it may take a while for V-belts to warm up enough to overcome the set they take on while sitting parked on the pulleys for several days.

Poly Vee is at least as good as any belt I've seen for being smooth and quiet. They are a good replacement for applications requiring matched V belts, as the PolyVee can be ordered wide enough to use one belt for the drive. That in itself may eliminate one source of belt vibration.

I have no complaints about the PolyVee drives I have on one lathe and one mill.

 

[AlexO]

Yes. I checked everything and no luck. Once they're warm they're better. I'll go for poly v.

 

[dennh]

Alexo, If this is on your Harrison, I know what you mean. A VFD will partially solve the problem as you can avoid speeds that causes resonance of the belts, motor, frame, etc. I've thought about changing to a Poly-V belt but didn't want to eliminate the stock brake which uses the V sheave. Den

 

[Hawaii Machinist]

Alexo
I have a Logan 10" lathe that I removed the crowned flat belt pulleys and machined them flat and grooved for poly-v belts about 15 years ago. It's the best thing that I ever did to it. My reason was that the flat belts would slip too much, and the poly-v solved that problem. I never had any vibration problems, though.
Aloha,
Doug

 

[Forrest Addy]

You might want to change from standard V belts to those having the narrow edge notched up to the tension element. They feature much greater flexibility and less trouble with resonance and rumbling.

This belt style is like standard un-notched belts in all particulars except for greater flexibility and an ability to run efficiently on smaller pulley diameters. They have "X" as a suffix to the section designator "AX" "3VX" etc.

 

[AlexO]

Thanks Forrest- I'll call GoodYear and see what's available. I take it you're not fond of polyV ??

 

[Limy Sami]

Poly Vee's are the way to go, IMO. Contact Gates for their design guide, explains what you need to know in pretty fine detail.

Take care. Sami.

 

[dennh]

I went thru the notched belt phase but they were not matched well. Then went thru Goodyear matched belts (no good), Browning matched belts (not much better) and finally, after paying a lot more for belts than should be necessary, I pulled two matched belts (by me) off the shelf at the local VIP auto. Standard Goodyear belts and the first two were closer than any of the matched series

Poly-V (Micro-V) will be next ... and last

Den