Small (20mm 10mm bore pulley) – source of?

[Andy_HParticipant @andy_h]

Not sure if this is the right topic – but seemed the closest match!

I need a 20mm pulley for round belts with 10mm bore (preferably aluminium). I found one on Amazon (although one reviewer said the bore was actually 8mm) and one on Aliexpress. Both reasonably priced but very long delivery time so obviously coming direct from China with all that entails.

I've spent several hours searching via Google but can find nothing from a UK supplier.

So just wondering if anyone has a "go-to" UK supplier they would use for such components – one that has evaded me in all my searching?

Andy

[Andy_HParticipant @andy_h]

[noel shelleyParticipant @noelshelley55608]

I take it you cannot make one ? It would be quite easy ! Noel.

[Andy_HParticipant @andy_h]

Posted by noel shelley on 03/10/2023 15:50:58:

I take it you cannot make one ? It would be quite easy ! Noel.

I could make one, once I've got a pulley this size on the new motor to get my lathe working. I think the term is "chicken and egg"

Andy

[Benedict WhiteParticipant @benedictwhite51126]

Ah. Where are you roughly Andy?

[noel shelleyParticipant @noelshelley55608]

I have some alli bar 1" I think, give me dimensions I should be able to make it ? Noel.

PS I have yards of bar so I can send a spare bit as well !

Edited By noel shelley on 03/10/2023 17:19:16

[Benedict WhiteParticipant @benedictwhite51126]

I have loads of aluminium bar too, purchased from the scrapyard at £2 a kilo, though I don't have a tool with a profile for round belts.

[noel shelleyParticipant @noelshelley55608]

I don't either but I have a radius gauge, a grinder and plenty of tool steel. Noel.

[AJAXParticipant @ajax]

Does it matter if the pulley is aluminium rather than steel? Just curious to know. If I were in this situation, I'd just bodge a temporary one from anything I had to hand, then make a better one.

[Howard LewisParticipant @howardlewis46836]

Sorry to be Job's comforter.

A 20mm OD pulley with a 10 mm bore will only have 5 mm wall thickness into which the belt groove can be cut.

What section round belt will the pulley be for ?

This suggets that the belt will need to be a pretty small section, say 6 mm max. This would allow a half round groove 3 mm deep, leaving only 2 mm wall between the bottom of the groove and the bore of the pulley.

Howard

[Benedict WhiteParticipant @benedictwhite51126]

Fair point Howard.

Ajax, I suspect it does matter though aluminium is easier to cut.

[Martin ConnellyParticipant @martinconnelly55370]

If it's only to get the lathe working then it does not need a long life so a 2mm wall will last long enough to make a replacement at some point.

Martin C

It occurs to me also that if the pulley can be mounted on the end of the shaft and the motor positioned to suit you do not need a through bore so the wall thickness can be increased.

Edited By Martin Connelly on 03/10/2023 18:20:53

[Peter Cook 6Participant @petercook6]

If you have access to a 3D printer, printing a pulley for temporary use works well. That said the "temporary" set I made for my Watchmakers lathe back gear is still in use some three years later!

[Neil WyattModerator @neilwyatt]

I was going to suggest drilling a hole in a bit of bar and using a round file while it spins on the motor to make a groove in a temporary pulley.

If there's a bigger pulley on the lathe to keep the belt aligned, you could just build up the motor shaft with masking tape, this would work well enough to make a pulley.

Neil

[Andy_HParticipant @andy_h]

Posted by noel shelley on 03/10/2023 17:09:20:

I have some alli bar 1" I think, give me dimensions I should be able to make it ? Noel.

PS I have yards of bar so I can send a spare bit as well !

Edited By noel shelley on 03/10/2023 17:19:16

Thanks for all the replies. Answering a few points raised.

Noel – I will send you a PM.

The belt size will be 6mm.

The difference between diameter and bore had occurred to me and I think the blind bore approach would be best as I freedom to position the motor accordingly.

No it doesn't have to be aluminium. I did say preferably but if pushed to explain that preference it might be difficult to come up with a good argument!

Andy

[JasonBModerator @jasonb]

I think the usual rule of thumb for round belts is minimum pulley is 4 x belt diameter so you might want to think again about size

[peak4Participant @peak4]

Posted by JasonB on 03/10/2023 20:02:48:

I think the usual rule of thumb for round belts is minimum pulley is 4 x belt diameter so you might want to think again about size

According to Simply Bearings, the minimum pulley diameter for a 6mm round belt is 57mm
https://simplybearings.co.uk/shop/p20247560/6mm-RPN-Type-Round-Volta-Conveying-Solutions-Cord-Belting-(Green)/product_info.html

However, if a 6x4mm Mini V belt will fit the headstock pulley, then the recommended minimum size for that is only 20mm.
https://simplybearings.co.uk/shop/p680016/Optibelt-VB-6×280-Li-Cogged-Classical-6mm-Wide-4mm-Deep-V-Belt/product_info.html

Still need to source or make a pulley of course.

Bill

[Nigel Graham 2Participant @nigelgraham2]

For a round belt pulley, you could free-hand grind a tool-steel blank to a semicircular edge to match a radius-gauge.

Alternatively make a simple tangent tool-holder to use a piece of round tool-steel or hardened and tempered silver-steel.

[not done it yetParticipant @notdoneityet]

Not knowing any further details, but I would likely change the belt type – unless it is a special requirement – if practicable. Multi-V comes yo mind.

[JuddyParticipant @juddy]

There is this which may get your lathe running: 20mm OD Motor Pulley (Suits Folding Doors) (reeley.co.uk)

or from Amazon : 20MM Single Groove Pulley 4/5/6/8/10MM Fixed Bore Pulley Wheel for Motor Shaft 6MM Belt (10mm) : Amazon.co.uk: Business, Industry & Science

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