pulley dims for boxford csb

[BillTodd]

Brian, I looked at my brothers AUD to day but it appears to have a different (modified) drive system :(

As jonnydeen says, the simplest way is to work it out backwards
i.e. if the spindle is to run at 1300rpm at its highest speed, then work out the ratio of diameters of the small spindle pulley and the large intermediate pulley

These are probably in to order of 80 and 120 so ratio is 4:3 which means the intermediate shaft will rotate at 3/4 of the speed of the spindle = ~1000rpm your motor does 2800rpm so you need a larger motor pulley (1000/2800) about a third of the size of the smaller high speed intermediate pulley.


The fastest slow speed quoted above is 450rpm 3/4 of that is ~337rpm so the small motor pulley has to be 337/2800 = ~8.3 times smaller than the slow speed intermediate pulley (In the picture it looks to be about 250mm diameter the motor pulley will be in the order of 30 mm which is a very small pulley for an A section belt! )

If you let us have the actual dims we can work it out for you.