DRO Displays

The displays for the axes of the DRO are going to be LED digits. I have some modules that use the MAX7219 chip and have 8 seven segment digits plus decimal points. One Arduino UNO and some code and we have a trial display:

So now I have a display and a gauge attached to the lathe. I thought it would be a good  idea to check the DRO gauge and see if it would be useful. It's not worth going through the hassle of building all the gauge channels if it doesn't work very well.

The first attempt was OK, but the gauge didn't slide very freely. Some adjustment of the gauge mounts might be a good idea. After some gentle filing the gauge freed up and all worked quite well.

I set the lathe dials to zero and the gauge to zero as well to check the calibration between the two measurement systems.



After moving a distance from the zero, I noticed that the gauge didn't match the scale. I finally found that when the gauge read a round number of millimetres:

The scale on the handwheel isn't at zero. I was about to give up on the DRO until I noticed that the ball on the handwheel was in the zero position.



So the dial had slipped when moving the handwheel. It looks like the DRO was more reliable than the dials in this case. Looks like it is worth continuing.