Cheap digital caliper DRO
I can't remember how I stumbled on this idea. I think I noticed the connector on a set I had, and thought I'd Google it. I was thinking this would make building a CNC mill easier: no need to worry about backlash in the hardware: just measure where you are. Anyway, a long time later, I asked myself the question: how can I use the mill to accurately cut a square hole. My X-Y table doesn't have stops, and it has terrible backlash. I found a youtube video which used a DRO to do it, and was reminded. There are lots of articles on this. I've used this one at nerdkits.com as a starting point for the adapter. It provides an easy power supply circuit. I bought some sets of stainless steel callipers on ebay which turn out to be complete rubbish. I've just soldered some wires onto the terminals so I can play with them using a breadboard: On reassembly, they mostly work after some screw re-tightening, but are a bit jittery. I think I won't do that again: I'll...