About 40 years ago, I fabricated this pantograph shape cutting machine. I first used it with an acetylene cutting torch, and later with plasma arc. It used a Grainger gear motor and an MRC model railroad transformer.
While this wasn't the first such machine that I had built, it was the first to use a magnetic tracer. The magnetic tracer was arrived at after a good bit of experimentation with rare earth magnets, which were new (at least to me) at the time. The whole deal sat on an empty 55 gallon drum, which I had to take care to empty before it got too heavy.
The second photo is a more recent version made largely from 8020 aluminum extrusions. It uses the same magnetic tracer.