Motor Belt for Electric Focuser

[Holliday]

I have the focuser as shown here: http://i.imgur.com/UAPTFzh.jpg and the drive belt is around 3 inches in diameter, I ordered some of similar size from ebay but the rubber was very soft and stretched almost twice as much as the original could, thus can't really be used as the focuser builds up tension then turns the knob suddenly and quite a lot. The originals appear to have worn out and both snapped, if anyone knows where to get similar which would work just as well that'd be great.

Thanks!
 

[brantuk]

Does the belt have a circular section? If so what diameter is the section and what overall length is it? I'd look under "drive belts" or "small cam belts" - the dimensions would help.

[Holliday]

On 28/11/2016 at 16:30, brantuk said:

Does the belt have a circular section? If so what diameter is the section and what overall length is it? I'd look under "drive belts" or "small cam belts" - the dimensions would help.

The circumference is 200mm and diameter 70mm. These are the ones I ordered previously: http://www.ebay.co.uk/itm/10pc-Rubber-Drive-belt-Pulley-Model-Motor-DIY-Toys-Black-2mm-X-70mm-/291512042475?hash=item43df78c3eb

But as I say, the rubber was too elastic and couldn't provide the right tension compared to the originals

[Bizibilder]

Try "O" rings of the required dimensions - they are not designed to stretch (much!) and would probably do the job for you.  Order by outside/inside diameter and diameter of the belt section.

[Davey-T]

Is it possible to change to a "proper" drive belt ? save any more problems in future.

See link

Dave

http://www.motionco.co.uk/

[Holliday]

15 hours ago, Bizibilder said:

Try "O" rings of the required dimensions - they are not designed to stretch (much!) and would probably do the job for you.  Order by outside/inside diameter and diameter of the belt section.

Ah lovely, this brought up a lot more items on Ebay, much appreciated!

 

15 hours ago, Davey-T said:

Is it possible to change to a "proper" drive belt ? save any more problems in future.

See link

Dave

http://www.motionco.co.uk/

I imagine it's very possible but not sure how I'd go about attaching a pulley to the focus knob.