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View Full Version : Sourcing and making Poly-V belt/ ribbed belt pulleys



MattiJ
01-23-2018, 04:31 PM
In another thread I mentioned making these poly-V pulleys.

Just a heads up in case anyone else wants to buy cheap pulleys:

Automotive alternator pulley is abouts 45 to 63mm and you can get new ones for less than 10 euros a piece when you find right shop. 20euros a piece gives you already plenty of selection. 17mm bore seems to be most common.
Power steering pump pulley is something like 100 to 160mm diameter, I haven't found any new source for these but junk yard in eastern Europe sent me one for 10 euros including shipping
(Audi A4 pulley, about 150mm pitch diameter)

Automotive sized PK belts are easy to find in sizes between 700 and 3000mm.

"Industrial" Taper-lock pulleys were crazy expensive with several weeks lead time. Other belts than automotive sizes are not too easy to find either. (still easier than pulleys)

Mark Rand
01-23-2018, 06:48 PM
I've got two 250mm x 85mm disks of aluminium waiting to be turned into poly-V step pulleys for my milling machine. I have got the belt, but am quite worried about how small it is. J section with four grooves for 2hp. It's tiny!

johansen
01-23-2018, 09:29 PM
I've got two 250mm x 85mm disks of aluminium waiting to be turned into poly-V step pulleys for my milling machine. I have got the belt, but am quite worried about how small it is. J section with four grooves for 2hp. It's tiny!

Figure 50% efficiency for a car alternator, so its not that bad.

lakeside53
01-23-2018, 09:54 PM
I've got two 250mm x 85mm disks of aluminium waiting to be turned into poly-V step pulleys for my milling machine. I have got the belt, but am quite worried about how small it is. J section with four grooves for 2hp. It's tiny!

The hp transmittal capability of the J section belt is quite high, but it depends on the speed and the pulley wrap. Graphs are available... https://www.myodesie.com/images/wiki/2/Cross-Section_Selection_Chart_edit.png


I have no issues getting reasonably priced J-section belts in the USA and pulleys are dead easy to make. I get a stock cast iron taper lock "B" belt pulley, turn off the sheave and insert a 6 (or more) groove j belt poly-v profile on the remainder.

Like this (follow link).

http://i238.photobucket.com/albums/ff150/lakeside53/Clausing%20conversion/DSC_9049Custom.jpg

http://i238.photobucket.com/albums/ff150/lakeside53/Clausing%20conversion/DSC_9051Custom.jpg

lakeside53
01-23-2018, 10:09 PM
Figure 50% efficiency for a car alternator, so its not that bad.

cars are typically K section.

J Tiers
01-23-2018, 10:18 PM
Making the pulley is not difficult. I think I made one in cast iron way back when I only had a lowly "109" lathe. That one is still working.

Just takes grinding a cutter to fit, and doing some measuring while making the part. I was reducing the diameter a bit to get a different speed ratio, so I had grooves to fit the cutter to.

velocette
01-24-2018, 01:32 AM
I've got two 250mm x 85mm disks of aluminium waiting to be turned into poly-V step pulleys for my milling machine. I have got the belt, but am quite worried about how small it is. J section with four grooves for 2hp. It's tiny!

Hi mark with apologies Matti being a Poly Vee addict had to jump in
Six ribs will fit OK as 85 / 4=21.25
6 ribs j Poly Vee = 14.04 + 2.34 = width over grooves 16.38 will fit OK. Make the outer diameter of the pulley 4 to 6 mm greater than the crests of the Vees.
Alignment is critical shafts must be parallel and groove lined up and tensioned.

MattiJ
01-24-2018, 03:34 AM
The hp transmittal capability of the J section belt is quite high, but it depends on the speed and the pulley wrap. Graphs are available... https://www.myodesie.com/images/wiki/2/Cross-Section_Selection_Chart_edit.png


I have no issues getting reasonably priced J-section belts in the USA and pulleys are dead easy to make. I get a stock cast iron taper lock "B" belt pulley, turn off the sheave and insert a 6 (or more) groove j belt poly-v profile on the remainder.

Like this (follow link).

http://i238.photobucket.com/albums/ff150/lakeside53/Clausing%20conversion/DSC_9049Custom.jpg

http://i238.photobucket.com/albums/ff150/lakeside53/Clausing%20conversion/DSC_9051Custom.jpg

Anpther pretty good design guide including basic pulley dimensions:
http://www.optibelt-usa.com/fileadmin/files/Catalogs_and_Manuals/TECH_MANUAL_RIBBED_BELTS.pdf

I did one pulley from mystery steel and canít say it was dead easy if not too difficult either. With K profile you need to cut about 8mm wide chip or take gazillion smaller chips if you get too much chatter.

Noitoen
01-24-2018, 06:28 AM
For taperlock use, you can buy a ready made female cone to adapt/weld to a normal pulley:

http://www.fptgroup.com/dss/docs/689_06_Fenner_Shaft_Fixings.pdf

EVguru
01-24-2018, 10:10 AM
If the large pulley is more than about five times the diameter of the small pulley, then you don't really need to groove the larger pulley, just the small. The torque transmission will be limited by the small pulley.

MattiJ
01-24-2018, 11:43 AM
If the large pulley is more than about five times the diameter of the small pulley, then you don't really need to groove the larger pulley, just the small. The torque transmission will be limited by the small pulley.

This is taken to extreme on washing machines, belt pulley ratio is something between 15:1 ... 30:1

lakeside53
01-24-2018, 12:01 PM
Anpther pretty good design guide including basic pulley dimensions:
http://www.optibelt-usa.com/fileadmin/files/Catalogs_and_Manuals/TECH_MANUAL_RIBBED_BELTS.pdf

I did one pulley from mystery steel and canít say it was dead easy if not too difficult either. With K profile you need to cut about 8mm wide chip or take gazillion smaller chips if you get too much chatter.

You can also step-rough it then profile in a couple of final passes.

MattiJ
01-24-2018, 05:40 PM
i wouldn't want that for lathe less than 5-10 hp :p

edit: this post was reply to "someone" posting 6 tooth profile tool. Seems like he did ninja edit later on and now my reply looks like out of place :p
Should always quote the poster you are answering ..
http://www.machinery.co.uk/article-images/75578/NTK-Cutting-Tools-Poly-V-260215_popup.jpg

lakeside53
01-24-2018, 07:29 PM
Way less with J-section ;)

Peter.
01-25-2018, 02:09 PM
Making the pulley is not difficult. I think I made one in cast iron way back when I only had a lowly "109" lathe. That one is still working.

Just takes grinding a cutter to fit, and doing some measuring while making the part. I was reducing the diameter a bit to get a different speed ratio, so I had grooves to fit the cutter to.

Is this the pulley type that John Stevenson said he made hundreds of using a 11TPI thread chaser? I bought a chaser I found at a tool shop just in case I ever had to make such a pulley.

lakeside53
01-25-2018, 09:17 PM
Yes, but not everyone agrees with him. Pretty easy to just make the right tool and step it over the specified distance.