Clarke CL300M motor axis diameter

Hi everyone,

I need to change the timing pulley of my CL300M lathe, the spare part I received from ARC (C3-148 Motor Timing Pulley) has an internal diameter of 8.85mm but the axis of the motor has a diameter of 7.91 mm, so of course the pulley moves around. Are there several models of these lathe, where the axis diameter has been changed? Any help much appreciated! As I don't live in the UK anymore, I can't just bring the lathe to a shop

many thanks!

Thomas

Is the lathe useable at all? If so you could bore the spare oversize to fit a plug in it and re-bore to the correct size. Another option would be to use some drink can to shim the pulley. It may take a few layers as the wall thickness of cans I have measured is 0.1mm. Try a few other things like oil cans, you may find a more suitable thickness.

Martin C

Unfortunately I can't use the lathe, but will try using a shim the pulley - I ordered some copper sheet, 0.5mm thick. Thanks a lot!

Thomas

That's the problem with mini lathes ... different factories, different detail; specs

Consider a sleeve as suggested above. A temporary wrap of insulation tape may last long enough to make one.

Neil

CATCH 22!

As Neil says, make a "shim" while you turn up a bush. Although with only 0.94 mm difference in diameters it will be very thin (0.47mm - 0.0185" thick )

So 0.5mm shimstock will be too thick, and 0.015" shim will, be too thin!

Any chance that you could still use the original pulley, and bore out the new one to take a thicker sleeve, Say 10 or 12 mm OD (Standard reamer sizes ) and then make a bush with that OD and bored / reamed 8mm?

A 7.91 mm shaft in a 8 mm hole will only have a clearance of 0.09 mm (0.0035" ), so if you don't push the reamer too far in, the lead may proide just eniugh clearance for the bush to be a snug fit on the motor shaft.

If the poulley is metal, you could use the "Heat and freeze" rechnique to secure the bush in the pulley; and the interference might close the 8mm reamed bore to provide a close enough fit on the shaft.

You might even have to hand ream it until it is large engh to fit onto the motor shaft.anyway.

Howard

Edited By Howard Lewis on 07/04/2023 21:03:23

All those years ago, I fitted a sleeve made from copper plumbing tube to do just what Thomas wants. The sleeve does not to be a complete circle, cutting a bit out and squeezing it in to the required diameter worked perfectly for me. However, when the time came to pull the pulley off for the next iteration, it would not budge (and having been a Clyde- trained Land Rover driver brutality came easily to me). I bet that countershaft and pulley went to heaven together. Be careful !

Dick

An option might be to leave the motor connected to the power and _reduce_ its shaft a little (with a file, motor powered up) to maybe 7.5mm. Drill a lump of aluminium freehand with a 7.5mm drill bit. Loctite it onto the motor shaft. Again file it down as it is spinning until it fits the ID of the new pulley.

Nominal bore is actually 9mm and I suspect your shaft is 8mm nominal OD. Plenty of 0.5mm wall 8mm OD tube on the internet which you could sleeve it with just cut a slot out of it for the key to fit (may need a longer key) Shaft may be 5/16" but if pully is also under then should be OK

If you want to bore it out as it is only plastic you could just turn the spindle by hand or cordless drill but you then have the problem of cutting a keyway.

Edited By JasonB on 08/04/2023 07:47:11

Edited By JasonB on 08/04/2023 07:48:22

Hi Thomas, have you not tried contacting Clarke's service for the correct part Clarke service & support ?

Regards Nick.

Amadeal do an 8mm bore one but suggest contacting them to check it will work with your belt etc

Edited By JasonB on 08/04/2023 08:00:25

Hello Thomas,

Do you really have a Clarke CL300M, or is it some other make?

If you have a Clarke CL300M, then you have ordered the wrong spare.

A Clarke CL300M is a C2 - brushed motor base model mini-lathe.

A C3 mini-lathe looks different from a C2 / CL300M mini-lathe.

You have ordered and received Spare part C3-148 - which has a nominal bore 9.0mm as specified in the details on this page link

You should have ordered C2-148 - which has a nominal bore 8.0mm as specified in the details on this page link

• A C2 mini-lathe is the same as a Clarke CL300M, and to the best of my knowledge, made by SIEG.
• A C2 brushed motor is smaller in frame size than a C3 brushed motor, made by SIEG.

For further clarification, C2 and C3 and CL300M are brushed motor minilathes made by SIEG.

The above models are different from SC2 and SC3 which are brushless motor minilathes made by SIEG.

Minilathes from Axminster, ARC, Clarke, Zoro/Cromwell - Osaki, to the best of my knowledge are made by SIEG.

When buying spares, it is best to be sure about which SIEG machine you... i.e. specifically SIEG C2, C3, SC2, SC3.

Hope above informarion helps.

Ketan at ARC.

Hi everyone,

Thank you indeed for all the ideas - I now received the correct parts and managed to fix the lathe.

many thanks!

Thomas

Thanks a lot Ketan, I have now ordered the right parts (-should have asked before ordering...). Would you have recommendations for changing the timing pulley? The first time I did not put enough tension on the belt and it ate the new pulley pretty fast. I would have it done at a Machine Mart but I am living outside of UK now, so I need to do it myself.

best

Thomas

Hi Thomas,

Glad you have got the right items now.

It’s been a while since I did a belt change. It should be straight forward. Just make sure it’s running true. The motor mount needs to be correctly adjusted to make sure the motor is mounted horizontal rather than at an angle.

This is discussed somewhere in the past on this forum, but I am sure someone will be able to explain better if I failed to explain properly.

Difficult for me to check as I am away from office ( for the coming week) with limited internet access over the mobile.

Ketan at ARC

Dear all,

I have ordered 2 pulleys and replaced the old one. After a couple of hours of work, the pulley got damaged again -apparently I did not put enough tension in the belt. So replaced the pulley again with my second spare, tensioned the belt better (I could give it half a twist without too much force). A few hours of lathe work later... pulley is again damage with all the teeth grinded smooth. Any recommendations on how I should replace the pulley and tension the belt to avoid this? I'd love to bring it to a Machine Mart but I now live outside of UK and it's not an option... Any tips very much appreciated. Ketan from ARCEuro trade has been super helpful already.

Many thanks

Thomas

It would be interesting to know what sort of work you are doing on the lathe particularly diameter, material and depth of cut as overloading the machine could be the problem

Hi JasonB,

In the second run, I just drilled a 100mm deep hole (diameter 20mm) in mild steel, so not too much for that lathe model

best

Thomas

Dig you go straight in with the 20mm drill bit?

I do not know the lathe but to drill 20mm takes a lot of torque so overload could be the problem ? Noel.

No no, I started with 9mm then 10, 14 and 18mm using cutting oil emulsion