Tom, I really do not wish to belabor the point , however micrometers and proof loads were state of the art in the 1900's just as ether and Chlorophorm were for anesthesia. Neither are in use today. Today strain gauges and cumputerized instruments are state of the art. If you choose a lesser degree of equipment that is your choice. I choose the very best I can get and use the state of the art facility. If you wish "Doc Adams" to put you to sleep with flamable/explosive ether good luck finding a medical facility that will allow it. Best, Dr. BILL