Retrofitting The Graves Faceter for a Digital Readout

The Graves is unusual in that it appears to have been designed “with a clean sheet of paper” to be manufactured in large quantities, using mass production methods such as permanent-mold castings. Being a more “finished” unit, there is less flexibility for field modification. A few simple changes in design detail would have made this model simpler to retrofit, but it turned out there was a simple way to accomplish the digital retrofit after all!. To add to the challenge, this unit is left-handed.

It was only necessary to make the usual mounting bracket for the potentiometer, and a simple bent wire, 0.092 thick, of stainless steel to mechanically couple the potentiometer to the angle axis. Because of the packaging design of the machine, there was not sufficient room to mount the readout box on the head itself, so I built a separate box which the user can mount on the base, the wall behind the machine, or to the mast, with some simple attachment method like sticky-backed Velcro. The box is wired as with the other units. The box can be painted white to match the machine.

Here are some other views of the linkage details. The post which…