I've just fitted a Brushless DC sewing machine motor to my Pultra lathe. I used some of the motor mount parts that came with the complete package at £99. The motor is more noisy than an induction motor but the level of torque and speed stability at low speeds is very good. The Pultra is ideal for having the motor mounted under the lathe but I elected to mount the motor behind the lathe with the controller to the left of the lathe so everything is above the bench. The only custom part I needed to make was a 16cm x 16cm mounting plate with 4 hole in it. Two to mount the plate to the base casting and two for the motor and belt tension adjuster. My plate was 15 mm thick Ali but only because I had some to hand and I'm sure something thinner would be fine. I used a 5mm V belt to link the motor pulley to that of the lathe and the pulley cover provide in the kit was used to guard the belt from stray items.
If anyone want to PM me I can send some pictures and meanwhile will try to post them to the site.
Clive