Show us your home made tools

The thumbwheel on the brass part zeros the vernier. You still have to remember where you start from. In that position, you would zero on 0 or 1". In the middle somewhere, pic a whole number or build in your total move so you end on a whole number. I want to say the top rod on mine goes full length but I may be mi-remembering and it isn't on there at the moment. I nabbed that pic from the net