DIY auto feed for mill table

[th62]

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.

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.