How “plug and play” do you want this to be ?

Many years ago I bought an incomplete mini lathe from a Chester open day – the machine was complete apart from the electrical box, so no drive or control electrics for the “350W” brushed DC motor. As a basic speed control unit I bought a DC-51 conroller from Ebay

I have had this connected to the lathe & it runs the motor, but I have not yet got it fully installed (i.e safely enclosed & switched via an NVR circuit) and obviuosly no testing under load or over any period of operation. This unit is unidirectional, so will require a direction changing switch inserting between it and the motor to get reverse running (if your original arrangement did not include this) & also would require some form of NVR circuit on the incoming mains supply.

Before buying this I had come across a series of articles here where the writer had used one of these controllers on a Clarke mini mill, described the process & subsequently had reverse engineered the circuit to work out how it worked.

This is not a recommendation, just an indication of a lower priced solution which may work for you if you understand what you are getting into. This controller is apparently at full mains potential (though, apparently, so is the original Sieg board) so fiddling around here if you don’t understand what you are doing could have serious consequences – possibly fatal.

Nigel B.