Poor Mans go no go gauge

A Taper mandrel can some times be used as a go-nogo guage for work pieces involving holes. In this video, I bore a bevel gear center hole to close sliding fit for the crankshaft of a A flamelicker engine. The nature of the taper mandrel having one end larger than the other allows for checking two specific dimensions, with the nominal size directly in the middle.
A go-no gauge (or go/no-go) refers to an inspection tool used to check a work piece against its allowed tolerances. Its name is derived from 2 tests, the test involves the work piece having to pass 1 test (go) and fail the other (no-go). For the home shop machinest or model engineer, Inspection tools that allow accurate measuring below a thousandth of an inch, usualy becomes a "by feel" gray area. For me anyway. By using at least two and preferably three different calibrated outside micrometers, an average measurement of a position on the mandrel can be determined, thus the I.D. of the work piece can be measured to better than +/_ .0002" with confidence in the home shop with out high dollar inspection tools. = SHARE ROCKNTV1