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01-4-2013 14:37:20  #1

Bar-Let. Replacing the rollers

I finally got round to doing this, though I've had the materials sitting around for a while.

The problem with my Bar-Let was that the roller rubber had hardened flat, meaning it was virtually impossible to feed any paper through and turn the platen. You can see the three rollers in the picture below (marked with arrows - I took off the Bar-Let's cover to avoid scratching the paintwork). When the carriage is pushed to the right, a small catch is revealed that allows you to flip up the whole carriage assembly, making access very easy. (This picture actually shows the Bar-Let, after the repair, not before.)

The pictures below show the top two rollers (the third, on the bottom, was not too bad so I left it alone). On the first roller, the rubber had already started to crumble away to reveal the barrel. The rubber had the consistancy of hard, brittle toffee.

I should say that the rollers are secured in place with long brass pins (which turned out to be easier to pulll out than push back in).

Removing the rubber was simply a question of lightly crushing it with a pair of pliers and picking off the bits with my fingers. I then scraped off any residue with the edge of a coin.

To replace the roller material, I'd already obtained some sample lengths of hose from a company called 'Hose World' (I'll add a link in the resources section). Because of the distorted profile of the old rollers I had to estimate the original outside diameter as 7.5mm; the interior diameter (the width of the metal barrels) was 4.5mm.

I bought 1m samples of all the likely hose sizes that Hose World had to offer. The hose was fairly cheap, but, typically, for such small amounts, the biggest cost was the postage. I cut some ID 5mm/ OD 8mm neoprene hose to size to try it out. It worked perfectly, so I didn't bother trying anything else.

Job done. And with far less stress than anticipated. You can see the two new rollers in place below. They do rotate slightly on the barrels, but this causes no problems as far as I can tell.

A fine old machine now in A1 working order.


01-4-2013 15:05:29  #2

Re: Bar-Let. Replacing the rollers

Great stuff Steve! And a very interesting read. 

From your last photo it appears that the rubber hose is curved, that is it doesn't lie flat against the platen. I suppose it's soft enough to just bend to the platen? Or is the photo misleading me?

Oh, and the link you posted in the Resources sub-forum appears to be broken.

The pronoun has always been capitalized in the English language for more than 700 years.

01-4-2013 17:38:41  #3

Re: Bar-Let. Replacing the rollers

There is a slight bend, it's due to the inside diameter of the hose being 0.5mm wider than the barrel. Originally I was going to try and pack out the gap with a smaller diameter hose, but it didn't seem to make any difference to the Bar-Let's operation, so I let it be.

I suppose the key to it is that the width of the rubber has remained the same. In the original it was 3mm thick (7.5mm less 4.5mm) and the new hose is also 3mm (8mm less 5mm). I was concerned that the hose would be too wide to fit into the space available, but this doesn't seem to be the case; it turns freely and shows no signs of slipping off the barrel.

(I've fixed the problem with the link.)

Last edited by Stevetype33 (02-4-2013 13:43:31)

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15-5-2013 13:38:20  #4

Re: Bar-Let. Replacing the rollers

A postscript to this repair job.

I decided to revisit these rollers as I wasn't that satisfied with the fit of the replacement rubber tubing I put on. It didn't actually matter - you couldn't see them in normal operation - but I thought I could do better. 

What I did was go through my collection of hoses and experiment with a few other sizes. I cut short (5mm long) rollers to see how they worked, and found that I had some 3.5mmID/7mmOD nitrile rubber (NT) tubing that did the job very well. I then cut the tubing to the proper length and slid them onto the brass barrels.

This was a hell of a job as the barrels have significant rims on each end (the reason why my original outsized replacements didn’t slip off). It took about half an hour to push/pull them both on, and left my hands sore and cherry red.

But they’re a good fit. The OD of the original rollers was 7.5mm and because the new tubing is stretched over the 4mm barrels, they come in at around 7.4mm OD.

They grip the paper perfectly and look good. I’m happy now.

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