Poly-Vee Belts

Quick query re Poly-Vee Belts. Seems they can come with a variety of variation of ribs - 4, 6, 8, 12, 16 etc. I presume selecting the number of ribs required for a particular belt is dependent on the power required to be transmitted. The question is, what determines the number of ribs required for any particular application of poly-vee belt.

Or put another way, how does one determine how many ribs are required?

Chris

As with Vee Belts there are various different sizes of Poly Vee Belts.

Let me have your details via a PM and I will send you a PDF catalogue showing all the details.

Phil

Phil - pm sent!

Chris

Have a play with this, Chris

**LINK**

https://www.hutchinsontransmission.com/resource-center/online-calculation-softwares/poly-v-design-online

MichaelG.

Hi Chaps

New to the forum, have just inherited a small lathe (Zyto) which has flat cone pulleys on the spindle and countershaft. It has a flat belt with it that was stapled together but it is too wide, making only the middle pulley usable. I need to relocate the countershaft as the original setup has been lost. So was thinking, I will locate in a way that is convenient and cost effective for belts. So among these corridors has anyone run a regular poly-v belt inside out on flat pulleys ?

ie the flat portion of the belt in contact with the pulley ? Or has anyone ran "A" powertwist on flat pulleys ?

Thanks

The use of pollyv is very common normally suggested to be run inside out ie flat side to pully but also mentioned that the rubbery v inside handles more power. The disadvantage is that the spindle has to be taken out to thread it into the belt.

Thanks Baz. So the V ie normal side handles flat pulley ok too ? How about Powertwist belt on the flat ?

.

It is used that way in [probably millions of] Tumble Driers

Small Poly-Vee pulley at the motor; and the belt wraps either round the drum, or large flat pulley.

MichaelG.

I know when i changed my Serpentine belt on a Renault trafic van. The dealer asked is it 5 ribs or 6. I said i'm not sure. The next question was does it have air con. Yes. So it needs to be the 6 rib belt. Without air con it only has 5. I take it the more ribs the more power it can handle. Best answer i can give to the question asked.

Steve.

Hi Chris

Poly vee belts populate my workshop 4 PJ ribs up to 1hp & 6 PJ ribs on 2.5 sawbench.

Eric

Can you re-machine the flat belt pulleys to accept poly vee properly? I do realise you'd need access to another lathe

I run a poly v belt on the flat pulleys on my old Drummond M type. Seems to work best with the vees contacting the pulleys. The back of the belt seems more slippery. From memory its an LK series belt about an inch wide.

Cutting the v grooves in the pulleys has been on the round tuit list for some years. Main advantage would be less belt tension on the bearings.

Yes of course it is.....Thanks for jogging my memory !

Thanks to other gents who responded, haven't got time to reply individually now but appreciate the assistance. Can you acknowledge a post with a like or thumbs up type click just to show appreciation ?

I'm led to believe that cows don't live forever. Leather beltig is available. I also have a length of some specialised rubberised modern belting but it has no ID marks on it. On another forum as an aside in another topic someone mentioned that they used fiberglass reinforced packing tape made up into a belt for a Southbend lathe.

If thnking of making grooves in a pulley I would suggest starting with an aluminium casting.

I have been using a toothed belt on it's smooth side to drive my Drummond lathe for years as I reckon it gives a better grip than leather and no changes in it's tension. Colin

Long live the cows. Cows lives matter

Cheers Colin

Not at the moment ...no but that could change as just been offered a Viceroy. It's like it's just starting to rain lathes in my life ! That can't be such a bad thing can it !?

I have been looking at this myself, and thouroughly endorse Micheal Gilligan's recommendation of the Hutchinson Transmission website application to have a play around with power levels, pulley sizes, speeds etc, having had a play with this recently.

My new application - looking at a belt drive conversion of a Warco WM16 mill. I am generally happy with this, but when I push it (not really that) hard, I get a severe 'shrieking' noise from the transmission area , no idea what this is (some resonance set up between the primary drive step down to the intermediate shaft and the secondary step driving the spindle?)

So, as said I have been looking at belt drive, step down of 4:1 could be a bit of a problem, 5000 to 1250RPM for lower speed range, therefore requiring around 25mm pulley on the motor to 100m spindle pulley, and around 120N or more belt tension. So twice this + overhang factor on the motor spindle, around 240N plus 20%, so 30kg or 65lb sideways pressure on the motor end bearing (at 25mm driving pulley, 5000RPM, 0.7kW), Bit concerned about motor bearing.

But for Bibnah:

My 'middle sized' lathe is a Zyto, and iniitially came with a leather belt which was very close to falling apart at the clasp between the leather belt ends. Many years ago I replaced the belt by a Halfords poly-v fan belt, seen in photo, with ribs down onto flat puuley. It is a little slightly wider than pulley width - abolutely not a problem apart from being to wide for the smallest pulley / highest speed,step next to the bull wheel, which would be too fast a settiing anyway. The poly-v works very well on flat pulley for this light loading, and you absolutely do not need to machine your existing pulley to fit.

Martin