Chester Lathe timing belt

I have a little Chester Multi-Mini lathe/Mill unit. I need new timing belts for this unit. I have bought these in the past from Chester Machine Tools but current requests for these belts from Chester has been met with "will have to see if we can source these". A previous order to Chester in 2014 had the following Product code "203-S-029A" and Product description as "Conquest Lathe drive belt 1.5M-100-9.5" - none of which appears to make sense when compared to the physical item as follows:

These appear to be unusual belts in that the pitch is 4.2mm (as far as I can estimate from measuring over 10 teeth (front edge to front edge), 10mm belt width, with 83 teeth. These (I think) are reinforced polyurethane belts. The width and length are not critical as I could make an idler tension wheel to take up slack - but the unusual pitch is the problem.

So - are 4.2mm pitch timing belts made? 4.2mm is not even close to an imperial size. The other option would be to replace the driving cogs with 5mm pitch ones - then that becomes a new sourcing problem. The other option that I have been thinking about is just buy another lathe - slightly bigger (Warco, Axminster or Armadeal) and this could be my explanation to the wife.

You could try beeline engineering at Milton Keynes, google is your friend....

Or alternatively, if you go the 5mm pitch route, you could make your own pulleys, there was an article in a previous journal detailing the method using a formed fly cutter....

Is there any writing on the old belt?

Colin,

You may find this page useful: **LINK**

http://www.gatesmectrol.com/mectrol/brochure.cfm?brochure=3143

... each type has a link to its 'Pitch Details'

MichaelG.

John Rudd: Thanks but no joy there - although I haven't searched the entire site. I have sent them an email.

JasonB: No unfortunately. Both the old ones and the current one are just yellow transluscent polyurethane (I suppose) with about 11 reinforcing threads around the circumference.

Michael Gilligan: thanks for the link - but not sure which pitch type my belt is - but will look at this site in greater detail.

Some more information: just to reassure everyone that the 4.2mm pitch is correct, I bought a 168XL-037-84 belt from SimplyBearings - this being a 9.53mm wide, 5mm pitch and 84 teeth. When placed around the drive sprocket - it was obvious that the pitch was miles (well micrometres) too big as it just rode up from the first tooth onwards.

MIchael Gilligan: the site is very through but all pitch sizes close to mine are 5mm and the nearest imperial pitch size is XL at 0.2" - 4.2mm translating to 0.165354...."

The manual for the multi-mini is here: https://chestermachinetools.forumchitchat.com/post/manual-for-the-mini-multi-7111323

If the manual is correct the belt may be the same as the C1 lathe supplied by Arc Euro - http://www.arceurotrade.co.uk/Catalogue/Machine-Spares/C1-Lathe-Spares/C1-131-Timing-Belt although as far as I can tell this is an "XL" size belt of 5mm pitch.

Edited By Bizibilder on 02/06/2017 15:51:47

Edited By Bizibilder on 02/06/2017 15:52:09

I had the same problem some years ago- Chester had no spares then. Eventually sourced some in USA, but can't remember who. I have considered getting a rubber 5mm pitch belt next time and just shaving a little off the edge. Probably cheaper to buy/make new wheels to suit a standard belt. I'm assuming this is for the belt from motor to jackshaft.

I concur, the belt is the same dimensions for the Chester machine and the Sieg C1.......

http://www.arceurotrade.co.uk/Catalogue/Machine-Spares/C1-Lathe-Spares/C1-131-Timing-Belt

not sure on the 'XL' measurement...

Edited By John Rudd on 02/06/2017 16:37:21

My C1 lathe belt pulley will accept a Qualcast T 47169 belt (once it is cut down to 10mm wide!) and that is an "XL" size belt. If you google that code you should find similar belts listed. I ended up buying from fleabay/Hong Kong as 83 teeth is a non-standard size in the UK but 84 teeth are available.

In my case the Qualcast belt was a "short" and I have yet to modify the motor mount by extending the motor mounting slots so that it will fit.

Bizibilder has probably rendered this thought redundant, but:

[Colin] ... Is conceivable that your belt has stretched significantly?

I have no idea what reinforcement the specified belt uses.

It might be worth measuring a NEW belt [e.g. from Arc] before tearing your hair out.

I have a sneaking suspicion that the '1.5' might represent the 'half pitch' of the specified belt ... which would make it a 3mm pitch.

Of course, another option would be to carefully measure the pulley.

MichaelG.

Update: Dave at Beeline Engineering Products in Milton Keynes has offered to look at the broken belt I have just sent him. He also is puzzled by the 4.2mm pitch.

Gordon W: Yes - the belt from motor to jackshaft. The only other belt on the Chester is for the drive from the jackshaft takeoff to the milling head spindle.

Michael Gilligan: Yes I compared the broken belt with the new belt I put on by marrying up the truncated "treads" and they matched OK. If the belt had stretched, the current 4.2mm pitch would have originally been even narrower. With regard tp the pulley: a) the current "new" belt fits perfectly and I measured as best I could the distance between leading edge of one tooth to the leading edge of the next tooth with vernier calipers and it is 4.2mm.

To the rest: thanks for your great inputs: I will look into the C1 option and the others. I'm just hoping that Dave will come up with at least some more information.

If I don't come up with a suitable easy and cheap solution - I will get a new bigger lathe (ooh - goody!)

2nd Update: Bizibilder - I had a copy of the manual and should have checked. Anyway - yes it seems that the specification is the same for both the Chester and the C1 - so I have ordered a belt from Arceurotrade - now wait to see if it fits - I'll let you know the outcome - damn - how do I justify a new lathe if it fits?

You need a bigger lathe to machine bigger bits, the current machine cant cope.....easy...

It may help - if you are UK based, or don't mind a wait for the post - to know that XL belts are widely available. Try this:

**LINK**

Cheers, Tim

.

Fair point, Tim ... but; [despite Bizibilder's apparent success with XL] Colin has assured us that the pitch of his pulleys does not match that of XL belts.

MichaelG.

Final Update: Dave at Beeline Engineering Products on looking at the sample belt I sent him agrees that it measures 4.2mm pitch and had never seen one before - best he could do was a 4.7mm pitch belt.

Bizibilder & John Rudd: The (hopeful) purchased belt from Arceurotrade arrived this morning, looks the same as current belt, and fits perfectly (code C1-131, Timing Belt 1.5*83*10). But on measuring the pitch it is 4.2mm - so now confused as to actual pitch dimensions and standard designations.

In any case couldn't wait - a new Amadeal CJ18A lathe is arriving here tomorrow. Not quite what you big boys would use but will be perfectly adequate for my hobby uses. Avoided the wife's wrath by buying her a new Oak table and 6 chairs.

Thanks again for your help.

Colin