Putting some grip (stippling) on an aluminium drive pulley.

[JimDobson]

Putting some grip (stippling) on an aluminium drive pulley.

I've always wanted to work out a way to put some extra grip on a home made drive pulley to prevent or cut down on belt slippage. It would be nice to have the tooling that Wilesco use on their grooved pulleys. I had a Dremel saw accessory that the outer plastic shell broke and I thought what can I do with the saw blade. Rudimentary, but it worked well. I should be able to work out now a way to mount it so it doesn't need to be held, though its not as dangerous as that looks and being hand held allowed me to skew the saw blade at the various angles needed easily.

 

[RM-MN]

I think you will find that along with the extra grip you get from that you will also find excessive belt wear. The more common way to transmit more power is to use a wider belt and pulleys.

 

[BaronJ]

Hi Jim, Guys,

Knurling a shaft has long been a technique for improving the fit in a pulley bore.

 

[goldstar31]

I think the Health and Safety people might have might the same view as myself.
Initially, ther is ubsupported machining and secondly, the idea is gimcrack-- to say the least.

I'd welcome the thoughts of the qualified- which I am not

 

[fcheslop]

Probably would have had a size 10 boot up youre backside as you left the establishment
Keep counting fingers just to make sure they are all still attached

 

[BaronJ]

Hi Guys,

Whilst I understand what Jim was trying to do, I wouldn't have posted that video as a method of achieving the machining.

In my opinion it was a poorly thought out video ! Displaying a dangerous procedure. Certainly a practice not to be recommended.

 

[josodl1953]

Pulleys for drive belts should have a vee-shaped groove, making the belt wedge into the groove and thus create friction to transfer power from one pulley to another. The reason Messrs. Wilesco knurled their grooves on the steam engine pulleys was that they did not use ordinary belts ( rubber) but belts made of a long thin spiral spring. The idea behind this was that this type of drive was not critical on center distance ot the shafts. The attachments that could be used, for instance a circular saw or grinding equipment were just for show, not to do the actual job. So, the power transmitted was negligible and made the spiral spring belt ideal for the job. After all, we are talking about toys. I had a few of these attachments on my Wilesco steam engine long time ago back in the sixties when I was a child....

Jos

 

[IanN]

Returning to the original post:

What are you trying to do with the pulley system, and why are you using the belt/pulley you show?

If you want to transmit power you should use a belt/pulley designed for the job rather than taking a belt design/form intended to transmit little power and “over-rate” it (as others have already said)

If you must use the belt you show, a standard way of increasing the power capacity is to run two (or more) belts in parallel pulleys

Also, as already said by others, for power transmission a vee profile groove or a flat pulley with a crown is used, never a radiused profile groove

Finally - belt transmission has been in use for (literally) centuries, and in that time has been perfected through experiment and the development of engineering theory. Common sense suggests that if texturing the pulley was a good method of increasing the power capacity the all pulleys would be made that way .....

All the best,
Ian

 

[JimDobson]

Works very well for its intended purpose on Model & Toy Steam -

 

[JimDobson]

And happy to add no wear and tear to the belting

 

[terryd]

Returning to the original post:

What are you trying to do with the pulley system, and why are you using the belt/pulley you show?

If you want to transmit power you should use a belt/pulley designed for the job rather than taking a belt design/form intended to transmit little power and “over-rate” it (as others have already said)

If you must use the belt you show, a standard way of increasing the power capacity is to run two (or more) belts in parallel pulleys

Also, as already said by others, for power transmission a vee profile groove or a flat pulley with a crown is used, never a radiused profile groove

Finally - belt transmission has been in use for (literally) centuries, and in that time has been perfected through experiment and the development of engineering theory. Common sense suggests that if texturing the pulley was a good method of increasing the power capacity the all pulleys would be made that way .....

All the best,
Ian

Hi Ian,
we used to apply a bit of powdered rosin - the stuff violinists use on their bows - if a Vee or similar belt showed signs of slipping, but that was not often neccessary. If the pulley and belt are matched properly, then tensioned correctly slippage should not be a problem. We used lightweight round section plastic belting on small machines such as sensitive drilling machine with never any slippage problems, but they had elasticity could be stretched onto the pulleys for tension (not excessive of course, not enough to cause bearing wear) and didn't stretch,

Terry

 

[RM-MN]

Contrary to what one would expect, a little oil on a v-belt that was beginning to slip due to age and wear would cause it to grip better. It would get the farmer by during the last of the harvest when time was critical but that belt better be replaced before the next harvest.

 

[goldstar31]

Few of us seem to have forgotten( or just don't know' just how many uses rosin and other resins can be put.

 

[terryd]

Contrary to what one would expect, a little oil on a v-belt that was beginning to slip due to age and wear would cause it to grip better. It would get the farmer by during the last of the harvest when time was critical but that belt better be replaced before the next harvest.

What is very obvious when watching old farm machinery such as threshers or field saws is how slack the flat belts are. I was once told that is deliberate as it increases the length of belt around the perimeter of the flat pulley thus increasing friction. Tight isn't always a good thing.

TerryD

 

[Mechanicboy]

30 degree "V" shaped pulley is common to get better grip on the belt. Knurled pulley is not good for belt.

 

[goldstar31]

Whilst I was brought up in horse drawn machinery and steam traction engines, it was rarely safe for workpeople.

During WW2 my cousin made Spitfire oleo legs on a lathe and she wore a 'snood' to avoid trapping her long hair.

Incidentally- wide belt pulleys were 'coned' to keep them in track.
Then there was 'fast and loose ' ones.

It's all really ancient like balata belting- and underground conveyor belts-- and some were illegally used as transport underground to anf from the coasl faces. My father used to 'socket' the wire ropes that pulley the coal wagons to and from the mines to the staiths were coal was loaded for shipment.
We used to walk the waggon ways as shortcuts but we had to dodge the ropes when the wagons started to move. Our stuff was worked by gravity- and downright dangerous.

But mens' lives were cheap

 

[terryd]

H

Few of us seem to have forgotten( or just don't know' just how many uses rosin and other resins can be put.

Hi Norman,

We have forgotten many valuable things, some of which have been reinvented. For example, the 'Diamond' tool holder which holds the tool bit almost vertically, very similar tool holders are described and illustrated in a book published around 1860 by a factory inspector of which I have a facsimile copy. In the rush for the latest aids, CNC, carbide tooling we seem to have forgotten that past masters produced very high quality products using Carbon steel tooling, manual lathes and simple hand tools.

I went to an exhibition of the work of Maudslay and Marc Brunel (father of Isambard Kingdom B.) for the admiralty block making machinery at the London Science museum and Maudlay's screwcutting lathe was exhibited. I was astounded by the quality of his work and the precision involved - it certainly was outstanding when compared with any modern lathe of any manufacturer and the surfaces had been hand scraped and then finished to a high polish. But then again Maudslay was a 'Mechanician' of incredible skill at a time when there were many like him.

It's time we got back to basics and the forget the idea that throwing money at a problem will solve it or improve our skills.

TerryD

 

[terryd]

Whilst I was brought up in horse drawn machinery and steam traction engines, it was rarely safe for workpeople.

During WW2 my cousin made Spitfire oleo legs on a lathe and she wore a 'snood' to avoid trapping her long hair.

Incidentally- wide belt pulleys were 'coned' to keep them in track.
Then there was 'fast and loose ' ones.

It's all really ancient like balata belting- and underground conveyor belts-- and some were illegally used as transport underground to anf from the coasl faces. My father used to 'socket' the wire ropes that pulley the coal wagons to and from the mines to the staiths were coal was loaded for shipment.
We used to walk the waggon ways as shortcuts but we had to dodge the ropes when the wagons started to move. Our stuff was worked by gravity- and downright dangerous.

But mens' lives were cheap

Hi Norman,
My first, early training on a lathe, before I was allowed in the toolroom was with an old boy who produced small batches or 'one offs' of components for our special conveyors (one type of which were the wide belt conveyors for coal and mineral mines). The lathe he worked on and taught me on had the words cast into it's front headstock cover "Austin Motors - 1906", one of the originals when the factory opened at Longbridge. It had 4 thou' play in the headstock bearings but he could still make stuff to within 1 thou'. All carbon steel tooling, no messing with modern HSS stuff for him.

It was also belt driven with a cone of pulleys on the lathe and an opposing cone on a loosely hinged angle iron frame driven by a large electric motor which provided the weight to keep the belt in tension. we changed speed while the lathe was running by hitting the belt with the side of the fist. By the way, I think that you will find the term for the pulley profile is 'crowned' or 'bellied' rather than 'coned'.

TerryD

 

[goldstar31]

TerryD
I greatly appreciate another 'view of the last' because combined with today's knowledge, we can really mpve onn to greater things.

I had a really interested young man writing to me and who is desperate to learn. He has limited and old tools and this time asked about 'taper turning', I presume on his recently. acquired ancient rattle trap Clarkson grinder

So I wrote about the Morse Taper- and saif 'Really the sine should be 10 inches( and not 12) so that the offset can accept a 'Quarter of an inch'. Yes people might argue but that was the 'intention'

Again, case hardening which needed a ginger headed virgin boy's urine for the task. Of cours , chemically, it is so nearly right
Best Wishes

Norman

 

[chrsbrbnk]

the farmers don't have a slack belt intentionally and definitely not when under high load but the belt weight on a 100 ft 6inch wide flat belt 3/8 thick kind of sags itself and provides a lot of tension on the pulley faces the stippling does work a little more tough on the belt but its a model not a production machine a safer method would be using a purpose built handle for the saw blade or maybe just chuck it in the dremel and let the dremel free wheel