Although I have a nice milling machine, setting the dividing head vertically is something of a trial due to restricted headroom so I tend to use the Headstock Dividing Attachment and a milling spindle in the lathe for jobs such as drilling cylinder end plates. I have a Myford swivelling vertical slide and an Arrand milling spindle and set up using this arrangement:
or this
While satisfactory, this arrangement is a little cumbersome to set up quickly - it would be nice to have a self contained arrangement that could be bolted to the cross slide as a single unit. The opportunity came with the purchase on ebay of a Myford fixed vertical slide together with another Arrand spindle. I was then looking around for a small motor of 1/8 or 1/6 HP. It seems that the days of compact small induction motors has gone and sewing machine motors are usually thought to be a bit marginal in power. However, I came across this :
http://www.ebay.co.uk/itm/350453897010?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649.
This 120W package seems to be widely available from the sewing machine trade (though not necessarily described in such an enterprising manner). Taking my courage in both hands I ordered one. I decided to get the package with the foot pedal.
All I had to make was the bracket to hold the motor
Using a the spindle (which has a 1MT) I restrict myself to a 1/4" mill or drill. So, heart in mouth I did some tests. I have a cheap laser tachometer. With the foot pedal fully depressed the speed of the motor alone was 20,000 rpm. Attached to the milling spindle the no load speed was 4,100 with the supplied 3/4" pulley on the motor and the larger 1.75" pulley on the spindle. Trying the worst case I was able to mill a 1/4" diameter slot 25 thou (0.025") deep turning a 2 flute slot drill at around 2500. Drilling using a 1/4" stub bit again dropped the rpm to about 2500 (1800 with real pressure but this did not feel comfortable).
I am satisfied that the motor is up to the job and would also be satisfactory driving a small lathe of the Cowells type size. I don't think the simple resistor speed control offers anything to me, I was just using it as an on/off switch. Whether a thyristor speed control would be beneficial would be an interesting experiment and I would welcome comments.
I hope these notes may be useful, I'm certainly pleased with the outcome
Rod