Im going slightly mad trying to,source a belt that i can use with my external motor.
It needs to go around the oitside of the platter and to the motor.
I am after a thin round style belt and dont want to make my own.
Anyone able to point me in the right direction to someone i can buy from online?
Actually, this is an easy one. Look for an industrial O-ring supplier. Measure with a piece of string, very precisely, and then go anywhere from about 4 - 10mm shorter for the *circumference*. You will find that the material cost for these things is low enough that you might purchase a range of circumferences (size) and diameters (short way) and see which works best with least slippage.
Industrial O-rings may also be purchased in a variety of materials, the most common of which is neoprene. But there are several silicon and silconized materials also available. When you are sure of the correct size you might consider stepping up to the better material for longevity.
I have not purchased a "brand-name" drive belt in nearly 40 years and quite a few turntables since I found this source.
Melrose Park, PA