It's funny how you get used to using digital mics and callipers and for some even DROs, this last few days I picked up a job at work which despite being basic turning required finished diameters of 63, 55.5 and 39 mm to a tolerance of +0.00 -0.02
Most of the measuring eqpt at work is the old fangled (but always reliable) Moore and Wright adjustable anvil micrometers, so I was using 0-50 and 0-100 mm mics.
I had to re-learn turn of the mic, adding 25 or 50 to get the reading and the varying feel between the two mics to the standards after several years of being spoiled with direct reading gear in my home shop and working with smaller sizes. Only having enough of the material for one go meant being careful.
I always try to hit a specific dimension even when roughing as this helps to read the mic as I know what it was supposed to be, and only quick check is needed to ensure the thimble reads to the correct line. I also like this method as it allows you to gauge what DOC will work best for a nice finish with tipped tools as these often do not give shiny results with small finishing cuts.
Measure twice cut once as we all know, start with the bigger diameter and if it goes undersize make it the smaller diameter. Better an extra 15 minutes on the job than having to start from scratch.
I invariably make a male part first as it is easier to measure, then adjust the female to suit.
