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I have been asked to do some small repair work on two nice Museum model Cornish steam mining engines.

I need a drive band for one about 75cm  in total length and around 3 mm wide. The original has been replaced correctly with a glue  joined leather belt but it has failed - because the replacement was a flat belt which has been chewed up since the pulleys are essentially v shaped.  I think a round belt would do fine - i suspect an actual v shaped leather belt would be hard to get, but I have seen round ones.

It works fine with a rubber round section one  I found, but it would be nice to get a leather replacement.

Can anybody point me at a source ??

 

 The museum also has a unique model ship - Flower Class -HMS  Rhododendron - made in icing sugar !!!  Plus some souvenirs of the vessel

image.thumb.png.8da9208c2fcc5359a7ed9d27add2ad9a.png

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You might check in a jewelry supply store or website. They sell thin leather beading cord material for necklaces and bead stringing.

 

Amazon has pages full of it: https://www.amazon.com/Leather-Jewelry-Supplies/s?k=Leather+Jewelry+Supplies

 

Here's 3mm flat leather cord, too:  https://www.amazon.com/LolliBeads-Genuine-Leather-Braiding-Espresso/dp/B00BJ8Z5HK/ref=sr_1_102?dchild=1&keywords=Leather+Jewelry+Supplies&qid=1599013818&sr=8-102

 

It is also available in 2mm flat and, of course, various sizes of round cross-section, too.

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  • 2 weeks later...

Should Tony Griffith (as per link above) have run out of the round leather belting, I obtained such belting from Chinese sources via ebay in the past.

 

Such belting would be connected with two staples. That's historically historically correct, but doesn't make for a smooth running belt.

 

I have never seen leather V-belts, btw.

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This belt is glue jointed - would remake the joint but i cant get that extra bit of slack.

I think its too small  to be stapled - at least with my skills and kit.

 I rather presumed that v shaped belts were unlikely  but one of the pulleys is v shaped and appears to show signs of wear. 

But a round belt should be perfect - what is certain that a flat one as presently fitted is never going to last any time

I have found a rubber one which suffice but it would be nice to have a leather one.

 

Thank you chaps for the leads I will deal with the making a loop problem when I see what is available .

I was ratherr hoping there was some nice model engineering supplier who could magic one up fully made up to length ! 

 I will take a pic of the engine and post it .  I rather suspect it was a prewar "kit" construction.

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Mining engines would have actually had flat belts - round belts were only used on very small machinery. V-grooves for round belts would normally have an included angle of around 50° to provide for the wedging force.

 

The flat belts of old times were either sewn together or also stapled. In some cases a sort of hook system was also used. Pulleys for flat belts were slightly barrel-shaped to keep the belt centred - sounds counter-intuitive, but works.

 

You could drill a couple of thin holes cross-wise through the round belt on each end and then lash it together with either wire or thread. I have done this in the past, but for practical pruposes this did not run smooth enough on my watchmakers lathe (one sees the period bumps from the lashing on the turned surface ...). However, for a demonstration model this may be good enough.

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Unimat SL owners regularly use O-rings for drive belts on their mini-lathes.  Early versions of these lathes originally came from the factory with braid-worked fiber cord belts, laid up much like thin Turks' heads.

 

Below are three styles of wedding bands with decorative Turk's heads worked around them which illustrate the way in which a drive belt can be worked up out of round or flat material to form various widths of flat or round belting. These can be made from round or flat leather lacing or fiber cord. One advantage of this belt is that it can be adjusted for size (tightness) easily and its runs very smoothly. This is old school stuff, of course. The O-ring option has pretty much replaced braided belts. I haven't seen one in use in a long time.

 

 

 

13-117-t_5-2wy-goldturksheadring18K.jpg

 

13-R4011-8C-t-goldturksheadring.jpg

 

13-R970-8C-t-goldturksheadring.jpg

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