DIY auto feed for mill table

This is the auto table feed I built for the BF20 mill. The motor is a windshield wiper motor. Unfortunately when ordering these things there’s no way of knowing what speed they turn at. This one has three speeds, but is a bit too slow.

I first turned up two drive bushes, one for the motor the other for the table lead screw. The motor shaft is a splined tapered shaft. The leadscrew drive bush is also aluminium which is a neat fit over the leadscrew. I removed the key as a safety feature. Both drive bushes have four 8mm slots milled equal distanced around the bushes.

The clutch system relies on a four prong sliding bush. The prongs are 6.2 mm brass pressed into a 50mm round aluminium bush. The clutch bush slides along the leadscrew drive bush to engage the motor drive bush.

I did buy a variable speed motor controller with a reversing switch, but opted not to use it, instead I use a two way rocker switch for table direction and two momentary on, push button switches for speed control. https://www.youtube.com/watch?v=z0jBQFE0xUk


The rocker switch switches polarity to the motor, reversing its direction of rotation and thus direction of table travel.. The momentary on push button switches control speed.