I’m sure the model club will want to make lots of tiny bits. The spindle alignment was tested with 3″ of 1/2″ brass and I decided to call it a day when the difference between close to the chuck and 40mm out was only 1 micron. The chucks have the usual drawbacks, the large one has 200 micron runout at 100mm from the chuck generally, and the smaller drill type chucks vary from very good at some diameters to poor at other diameters with different sizes of drill blanks.

Now I understand the spot the difference, I had taken another photo at an angle and had difficulty getting them both on and did not notice the clone.

I used a Mitutoyo micrometer, not digital but a manual. It does take experience to get a repeatable “feel”. I sold all my digitals, I was not using them much after retiring and mostly use digital calipers, good for 10 microns if used carefully.