Looking for a flexible shaft coupler

[cuivenion]

Not sure where to put this. I’m looking for a flexible shaft coupler like this:

https://www.ebay.co.uk/itm/283138679258?hash=item41ec6161da:g:LvsAAOSwNaBeQ0Q~&amdata=enc%3AAQAIAAAA8FkdbYY5YqtiNfVgWHzqmj0YyQ3bRKpXWhkBu%2FxPc5sf7sORVLHE%2BjWT1vp9Z6EZ4nNfUCgI8WtcV%2BGKfzT47evS3bldWR40uSMXdgvTdMn0HEiuVwTIRLy3MS4rvCuPsfrSjnA6R5lTz9FhqA34Kkcpy1DCQ9ZmlF4VUfx5sQsnm7wRIMy%2Bka6kL974sIdd%2FdRt3ZePzlpS8RMJQbGRtJz2w9wQbZBCkQ5ndzxoK7nZG35XfH6duq1ryegihe8%2FfiuUV7N7bSc82sSMMcymQYUZ195fdkI2PcArtiE1rn0gKbehIcmg%2BSWfBsdW1TB38Q%3D%3D|tkp%3ABFBM3vnJ2vth
 

I need 2.5mm to 6mm bore sizes but I can’t seem to find it anywhere and I’ve had a good look. Any help appreciated.

[LuckieEddie]

2.5mm is a challenge to find - are you certain that's correct? I've found 2mm -> 6mm & 3mm -> 6mm on AliExpress but nothing for 2.5mm. You might have to go for a 2mm and bore it out.

[cuivenion]

Yeah that’s what I thought. I want to use the skywatcher autofocuser on the the 10:1 reduction gear of the skywatcher 130pds crayford focuser, the shaft is 2.5mm unfortunately.

[Mr H in Yorkshire]

To be clear, do you mean 2.5mm on one end and 6mm on the other of the connector?

[cuivenion]

Hi, yes 2.5mm on one side, 6mm on the other side of the coupler.

[Greymouser]

I did come across this, not sure if it helps, but it is 2.5mm, but to 3mm, but that should be doable, then an easy 3 to 6? ( With a little fiddling. )  I think, maybe. They seem to do required to, again maybe. https://uk.misumi-ec.com/vona2/detail/221006230387/

Probably easier to bore out a 2mm one really, even available on Amazon.

Interesting site though.

[cuivenion]

Thanks for the info.

[LuckieEddie]

As an alternative you could get a sleeve of brass with an internal bore of 2.6mm and an external diameter of 6mm and bond it onto the 2.5mm shaft with Loctite 638. Then you could just use an easy-to-buy 6mm - 6mm coupler. This would be a one way journey though, you wouldn't be able to remove the sleeve without a blowtorch. I could knock up the sleeve for you for cost+postage. Message me if you want to go that route.

[Naughty Neal]

I would simply get the 2 mm - 6mm one and bore out the 2mm to 2.5mm, it shoulld be aneasy task with a 2.5mm dril bit. Has to be simpler then gluing on sleeves

I needed a 10mm - 13mm coupler for a different task for a Nema motor but couldn't find the 13mm so ended up boroing out the 12mm to fit.