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Harrison M300 or M250 Pulley / Belts problem

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MichaelC

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Hello,

I have a Harrison M300 which needs new belts. I can't get the old ones off the spindle pulley because they're blocked on by the bolt that holds the head-stock onto the bed - and I'm certainly not removing that. They almost squeeze out but not quite, I could probably force them but it doesn't feel right and I fear getting the new ones on the same way would damage them.

So it looks like I need to get the pulley off the spindle - which is the bit I'm not sure about. The pulley has a cap on the end of it which is held on by two coiled pins and on top of that is an m8 machine screw that goes into the end of the spindle. I don't see a ready way of getting the cap off - I can't get a bearing splitter behind it to pull it off and I'm sure drilling out the coiled pins can't be the intended approach. I could maybe get a big bearing puller and pull the pulley of with the cap in place - but even that doesn't look Ideal as I can't really access the spindle to push against, I'd have to put a screw into it and push against that. I don't know how tightly the pulley is on but it certainly won't come off with hand pressure. The motor pulley came off quite easily with a puller but went back on with hand pressure after a tiny bit of cleaning, I suspect this would be similar.

The M300 manual shows the cap part without coiled pins, but mine has pins and they look original, the similar M250 has the same type of setup and the manual shows the pins. I'm not clear what the cap and m8 screw is actually for - except that it might be belt and braces to stop the key from working its way out.

Obviously I could really do without damaging any parts so I'd be really grateful to hear from anyone who has come across this before and can either provide advice on removing the pulley or some other way of getting the belts off and back on.

Thanks
 

AndyT

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I'm not familiar with that machine but if it's an ordinary wedge section v-belt, it might be possible to replace it with a link belt. These are made up of separate short pieces, a bit like a flexible bicycle chain. The big advantage is that you can thread the ends around pulleys and then join them together.
More info at this randomly chosen supplier website, but they are widely available in a range of sizes:

https://www.bearingboys.co.uk/Nutlink-V-Belting-1036-c
 

TFrench

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I have a harrison 13" which is the predecessor to the M300. Mine is on link belts but they don't go over the spindle.
 
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