Thread: Looking for a 16 rib J section serpentine belt...

This motor I have for doing the VFD conversion on my Rivett as an existing sheave I would like to try to use. It uses a 16 rib J section belt 1 21/32 wide. I cannot find a J section belt that wide, am I supposed to just use two 8 rib belts?

Its just a 5hp motor, a 8 rib will probably outlive the machine. I think heavy truck are 11 or 12 rib, and they will transmit over 20 hp for thousands of hours.

Originally Posted by jkilroy

This motor I have for doing the VFD conversion on my Rivett as an existing sheave I would like to try to use. It uses a 16 rib J section belt 1 21/32 wide. I cannot find a J section belt that wide, am I supposed to just use two 8 rib belts?

Not unless you want to implement two separate idlers, in which case a bit of a gap and a pair of 6-rib might be better. Doable enough though.

If non-stock - you order from a distributor high enough up the food-chain to be an authorized 'slitter'. They buy the belting in WIDE section, slice-off the width/rib-count needed. Not at all cheap though, more especially if length is uncommon.

But before you do that, ten-rib are more likely to be stocked, and even the older PolyVee before 'improvements' rule-of-thumb rates out at point-7 HP per rib, ergo 7 HP on a 10 rib. And that is for quite long durability, not just peak.

How many HP do you expect to pull, what is it worth to have more on-tap, and how much work is involved if/as/when you must change a belt?

Bill

Thanks for the prompt and informed replies guys. The motor is 7.5 hp at 1785 rpm. I did manage to find a 20 rib but still no 16. McMaster carries 16 rib pulleys but only lists 10 rib belts, I bet a call to them Monday will clear this all up. If 10 rib is good for 7hp then that will be fine for me. I don't see any reason to not run the 10 rib belt on the wider pulley. Thanks again. I'll try to find my card reader and post a pic.

IME Poly Vees will stand a lot more ''abuse'' than the manufacturers specs in both power and torque.


FWIW can you go to a K section? - quick comparison here.

Custom Multi Ribbed Pulleys, Multi Ribbed Pulleys


Tip;- If you can, match up with a common auto app,..... the belts are much cheaper and more easily available.

If you found a 20 rib, why not just slice off 4 ribs?
Randy

Originally Posted by Limy Sami

IME Poly Vees will stand a lot more ''abuse'' than the manufacturers specs in both power and torque.


FWIW can you go to a K section? - quick comparison here.

Custom Multi Ribbed Pulleys, Multi Ribbed Pulleys


Tip;- If you can, match up with a common auto app,..... the belts are much cheaper and more easily available.

Yes but 'common' auto and truck generally go only to 6 or 8 ribs. And are usually WAY too long, given their typically 'serpentine' paths, so even a pair of 'em is not assured to be readily found.

Bill

Originally Posted by ratbldr427

If you found a 20 rib, why not just slice off 4 ribs?
Randy

That can work. Proper 'slitter' machines are quite precise, but a box-knife should be good enough for a less-critical customer who needs but one belt.

Bill

Shit, "K" section? I didn't know those existed, now I have to measure the existing pulley and see exactly what I have. I just thought it was a J section, which was the only one I was familiar with, back soon with an update after I get certainty on what this is.

Originally Posted by jkilroy

Shit, "K" section? I didn't know those existed, now I have to measure the existing pulley and see exactly what I have. I just thought it was a J section, which was the only one I was familiar with, back soon with an update after I get certainty on what this is.

There are more, yet. But if that is what is on a 'scrounged' motor, what is on the lathe?

You may be going to entirely too much expense to avoid changing the motor sheave.

New ones are not cheap, but they are much easier to turn from scratch than a multi-groove Vee of comparable power handling.

And Vees waste more power as heat and offer shorter lives as well.

Bill

7 1/2 hp? Do you think the motor is original or has someone substituted a larger motor? I didn't realize they came in anything other than 5 hp.

I think I need to clarify. The lathe is a Rivett 1020F with a 5hp reeves type drive that is flat worn out and makes more noise than a 747 at take off. Parts for the reeves drive are near impossible to find and very expensive. I wish to remove the original motor, and attached reeves drive, and replace it with this new motor with fixed drive and vfd for speed control. I upsized from 5 to 7.5 to compensate for torque loss and the new motor has an encoder so I plan on using a flux vector type drive. I could just swap out the pulley that came on the motor for a regular V belt drive, which may be cheaper, but if I can use it, why not.

The existing drive provides an output range of 400 to 4000 from the existing 5hp drive in "open belt" or direct drive to the spindle. The new motor has a safe operating range up to 7200. I plan on setting up the new motor with a 1:1.75 ratio to get the same 4000 at top motor speed of 7000. At the original low end of 400 the new motor will be running at 700 which should give me good torque. Probably not as much as the geared down 5hp original but close. If there are torque issues I would gladly sacrifice some top speed and change the pulley ratio to one with a higher reduction. The machine also has two back gear ranges so low speeds lower than 400 in direct drive are not an issue. I have to get everything together because I use this machine all the time and can't afford for it to be down for a long period.

Originally Posted by jkilroy

The new motor has a safe operating range up to 7200. I plan on setting up the new motor with a 1:1.75 ratio to get the same 4000 at top motor speed of 7000.

I would really, really not want to rely on that. And I don't think you need to do.

At the original low end of 400 the new motor will be running at 700 which should give me good torque. Probably not as much as the geared down 5hp original but close.

Probably more than good enough, especially if your chosen VFD is 'CT' capable, in which case you can drop to half or less of that RPM and still be in decent shape.

If there are torque issues I would gladly sacrifice some top speed and change the pulley ratio to one with a higher reduction.

I suspect that you can actually go the OTHER direction.

Consider this:

'Whatever' section, J or K of the motor pulley .. can you fab either ..

- TWO machine-side pulleys, mount the motor to a swing-plate, and use a single 6-rib or belt trimmed to 7-rib so as to have a hi-low range to hand.

- ELSE fab a single machine-side sheave to match, but use a lesser belt-width at least for starters, if that gets you making chips faster - as it should do.

Idlers or idle-sheaves to take up length to allow use of more than one common belt size are little or no harm, either. Ex; 'dummy' A/C compressor sheaves for some vehicles instead of simply shorter belts (which may not have a clear running path in that case).

A common 6-rib will not last as long as an 8 or 10 or better - but it will last a good while at 5-7 HP.

Just do the grocery-store math on the load of water-pump, 100A+ alternator, power-steering pump, and air-con compressor over 60K + highway miles - and all that with multiple reverse-bends and at higher temps than your lathe will likely produce where the belt lives.

Bill

Back to basics, JK:

16-rib seems not so uncommon in J, K, PK, sections. Suspects are air-compressor drives and generator sets, so they even show up on ePrey and similar 'remaindermen', as in:

22189013 Poly-V Belt (16 Ribs)

Also here:

V-BELTS > MULTIRIB (POLY-V) BELTS > PK Section V-BeltsD&D Power Transmission Products

There are plenty more.

'Job ONE' is to measure the sheave you have and confirm WHICH section it really is.

Job TWO how long over both sheaves, and how much adjustment you can engineer-in to allow use of one if not two or even three 'off the shelf' lengths.

Bill

Consider also that your reeves drive MIGHT have been 60% efficient at best. You'll gain a lot just from the switch to poly-vee (or Micro-v as Gates calls them). Log onto the Gates website and download their V belt design guide. It has masses of tables so you can calculate exactly what you need. They also have their "Design Pro" software that will do all the calculations for you.

Vehicles are typically L or K, which is a lot heavier. I've made many J section pulleys. Assuming decent pulley wrap, one J rib is good for about 1.6hp max under nominal conditions. This is down-rated as speed falls. On vfd with a 1750rpm 3hp motor, and two identical 4.0 inch PD pulleys I use 6 rib J section down to a 400 or so RPM. I can get away with this on a vfd as hp falls with speed (assuming constant input voltage); at 400 rpm I get maybe 0.7 hp.

6 and 10 rib belts are easy to find. Without knowing more about your design (like the diameter of the motor pulley and or the service factor of the motor), I'd say 10 rib will work fine.




Poly-vee sheaves are difficult to find in some sizes. Sure, they are listed in catalogs, but ask for availability and you often get told 8-10 weeks. I needed a poly-vee with an internal bore of 1.75 inches, compression type mount (for going over an existing suspect surface) and a pitch diameter of 4-6 inches. Nothing available. So.. I made my own J section the easy way. Buy a QT SDS (or whatever) bushed A/B belt sheeve, turn off the V-belt metal and add on the Poly-vee grooves. A 5.0 PD B belt sheave will turn down nicely to a 4.0 PD Poly-vee. I can convert B to 6 groove poly-vee in maybe 10 minutes max. If you need more than 6 ribs, machine down a 2 belt B sheave.







Reeves sheave shot? Turn it into a poly-vee. This is from a Clausing 6913 lathe. The busted sheave turns down nicely to a 3.4 PD J-section poly-vee. For the sharp eyes : It's a tiny bit under spec on the shoulder width but I'm not concerned as it's cast iron and has a tapered face from the old sheeve. Next time it will be 3.25 PD!

Originally Posted by Lakeside53

Consider also that your reeves drive MIGHT have been 60% efficient at best.

About 70-75% 'at best' actually. But the belts cost the very Earth in higher powers, and a well-engineered PolyVee is closer to 98-99% best-case, and suffereth little even when used suboptimally.

Easy way to make a section Poly-vee - buy a QT SDS (or whatever) bushed A/B belt sheeve, turn off the V-belt metal and add on the Poly-vee grooves. A 5.0PD B belt sheeve will turn down nicely to a 4.0PD Poly-vee (4.030 OD). I can convert B to 6 groove ploy-vee one in maybe 10 minutes max. If you need more than 6 ribs, machine down a 2 belt B sheeve.

Two slugs of 5 1/4" dia. 8620 out of Speedy Metals seemed cheaper here (Burke #4 renovation).

Large assortment of NIB QD bushings already scavenged off ePrey. HIGHLY recommend those gadgets, BTW.

Waiting 'til the 10EE is under power again, as those 8620 rounds would be an all-week job - each - just to bore for the QD's on the 6" @las... and then they each want 5", 4", 3" ten-rib steps...

But some of us just don't 'DO' aluminium... '..our dreams are made of steel..'

;-)

Bill

Originally Posted by thermite

But some of us just don't 'DO' aluminium... '..our dreams are made of steel..'

;-)

Bill

The above are all cast Iron

Originally Posted by Lakeside53

The above are all cast Iron

Good stuff enough.

I just happen to like colour-case-hardening, hence the 8620....

;-)

Bill

Thermite and Lakeside, many many thanks. My previous experience with Poly-V belts is with my two K&T mills which both use a wide Poly-V. Based on my smaller mill, which is also 7.5 hp and has a 3" wide belt, I was thinking that a really wide belt like that was required. My larger mill, which is 15hp, has the same size belt, my guess is they standardized on the widest size to reduce inventory. Lakeside, that pulley rework is great, I may have a large browning sheave I can rework that is the correct size for the input shaft.

I had not considered the loss of efficiency of the reeves drive, and you are right, those damn belts are expensive.

Originally Posted by jkilroy

My previous experience with Poly-V belts is with my two K&T mills which both use a wide Poly-V. Based on my smaller mill, which is also 7.5 hp and has a 3" wide belt, I was thinking that a really wide belt like that was required. My larger mill, which is 15hp, has the same size belt, my guess is they standardized on the widest size to reduce inventory.

Cudda been worse. First one I ever saw was on a WW Grainger 'Dayton' El Cheapo air compressor. Such a belt-eating, belt screeching, belt-throwing POS we finally rebuilt it with notched B-section vee belting.

Years later I thot the auto-industry outright daft for adopting 'em for underhood use. But Detroit used STEEL pulleys, turned or stamped and form-rolled. Not undersized and die-cast crap.

Major difference, and I have since come to appreciate the PolyVee's several strengths well-enough to sub 'em where I once used nought but toothed Gilmer's (which 'cog' ...if only slightly).

Bill