Older Doall cylindrical grinding attachment

Hi all,

I'm starting a cleanup of an older Doall cylindrical grinding and indexing attachment, and cracked it open last night. It's a bit rusty, the worst being on the bottom of the sine table but I don't see any pitting at least.

Inside, there's a 3 step pulley system to give some speed change capability. The pulleys look like miniature v-belt pulleys (smaller than an "A" belt size), but the belt that's on there looks incorrect. It's basically a flat rubber belt, with one side longer than the other, kinda like a Nascar track. It works, but I don't think it's correct.

- can anyone advise what the correct type of replacement belt should be?
- can anyone tell me what the heck this type of belt is?
- also, what's the purpose of the tension arm above the belt? It appears to generate enough torque to drive the spindle without it, so why is it needed?

If anyone has a lead for a manual for this, I'd love to grab one.

Thanks very much!

Lee

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Not sure about the correct belt type/size, but seeing that, my first thought is that the pulleys are out of alignment making the belt crawl up the side of the pulleys. Is there any adjustment to get the 2 shafts more parallel? The tensioner should also help keep the belt squarely in it's grooves.

Hi M.B.

Thanks for the suggestion, but I don't think that's it. It's essentially a flat belt, so it doesn't sit flat/straight in the v-shaped groove of the pulley. It always wants to ride up one side.

The belt is longer on one side, so it looks like a slice from a cone (or a Nascar track). The pulley alignment appears to be correct.

Lee

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There are a number of possibilities for the belts.
If the pulley groove top with is 1/2” you might be able to use a 4L belt for fractional horsepower motor that is lighter or thinner than an A Belt and if a 3/8” top with it might be a 3L belt .
Some belts are notched on the bottom side to give more flexibility .
If you check out the their site Gates sells V belts in both 4L and 3L .
Truflex(R) V-Belts | Fractional Horsepower | V-Belts | Power Transmission | Gates Corporation
They also make narrower Ployflex V belts but I think they have a different V angle than the others.
If you take your pulleys or the unit to an industrial supply shop that sell Gates or perhaps Dayco belts they may be able to find a match for you .
I would expect that the Doall parts book may only give a DoALL part number.
Maybe you would be lucky enough that DoALL would be able to supply the replacement belt.
Regards,
Jim

Any help? Dumore Grinders & Dumore Drills | Operating Instructions they say to call for ''retired'' models.

Hi everyone,

Thanks for the suggestions. I'll give doall a call and see what they say -can't hurt

Limy - not sure if you misread, but my unit is a doall rather than a dumore.

Thanks again

Lee

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leeko said:

Hi everyone,



Limy - not sure if you misread, but my unit is a doall rather than a dumore.

Thanks again

Lee

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Click to expand...

Sorry, my oops, ..I'm blaming my age.

Here are pictures of the papers that were with one of those units I used to have. V-belt part no. 109 is not very helpful, of course. These things are quite old and I would be surprised if DoAll had any parts.

It would be a pain to install a new endless belt because the spindle would have to be removed. If I had to fit a new belt, I would use round urethane of the appropriate section (10 or 12 mm diameter) and weld it in place.

I have been using the Chinese belting from eBay and it works fine. I have the fancy Swiss electric belt welder, but it can be welded with a hot butter knife once you practice on some spare material. Use a nail clipper to cut off the weld flash.

Round Urethane Drive Belt Diameter 2/3/4/5/6/8/10mm Rough Surface Green 1M | eBay

Larry

+1 for the urethane belting. We had one of those units at a place I worked in the 80's. Handy tool for little jobs.

My 70-year old Doall ML bandsaw has a placard with reference numbers for Gates belts. I imagine you’d have found such a plate if it was to be found, but I’m certain that Doall will sell you the belts. Tricky part will be convincing Doall to just tell you what Gates belt you need...


Jeremy


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Thanks everyone! Great info. The urethane belt looks like a great option

Lee

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