Mark
Just to give you some idea of the costs of doing a simple single speed belt conversion on the spindle I have some data from an American source about doing the job on a Bridgeport clone (Supermax?) with taperlock fitting L section pulleys and timing belt. Mislaid the link unfortunately.
Drive ratio 1:1 using 2 equal size pulleys.
Pulleys 40 tooth, 3/8in L pitch, 1" wide belt :- Bearing Shop UK price approx £20 each
Taperlock bushes size 1610, (I think 1" and 1 3/8" shaft size for my 1 1/2 hp machine ):- Bearing Shop UK price approx £5 each
Timing belt, 3/8in L pitch, 1in wide, 92 tooth, 34.5in pitch length (876.3 mm) Bearing Shop UK price approx £2.
Prices include VAT so call it £60 with delivery. Similar to a new Varispeed belt methinks.
I haven't yet verified that the belt length is correct for a real Bridgeport or whether there are more economic ways of doing the job. I suspect that the motor will need an intermediate mounting plate with eccentric slots so belt tension can be adjusted by twisting the motor. I imagine getting the pulleys at the same height so the belt runs true may be "challenging".
The American reference also mentions adding an inexpensive import digital tachometer to read spindle speed.
I plan to just calibrate the speed control knob. It would be proper posh to fix the potentiometer to the original indicator dial. With the added bonus of confusing the heck out of wannabe machine borrowers.
Clive
PS Not convinced about the power rating for L section belt, found book figures of 1.53 Kw at 1000 rpm, barely 2 hp. 8M, the nearest metric size seems to be rated at around 4 kw at 1000 rpm see a few pages around https://www.beta-power.co.uk/wp-content/uploads/2018/02/Timing_Belt_Catalogue.pdf . But L section has been used and reported to be just fine so …
Edited By Clive Foster on 26/01/2021 22:46:24