* This special B & S 1/2" Micrometer is altered so it is able to measure tubing wall thickness... minimum hole size for it to fit into is 3/16" , it will read wall thicknesses from 0 - .500, The bottom anvil has a ball Radius for clearance on the inside of the tubing. The following is printed on the tool : 'English gage 225 Brown & Sharpe MFG. CO. Providence, R.I. U.S.A. Pat. No. 2555243'.
* This came from a retired, Rhode Island Machinist's tool box.
I have a variety of used quality Machinist Tools listed there.
