Sunday, October 2, 2016
Min and Max Gauges
No, not the kind that go in earlobes. In the early days of the gun industry, to make standard part sizes on the way to interchangeable parts, gun makes constructed their version of go/no-go gauges. A maximum size hole (for example, for a gunlock side plate) would allow parts to fall through if it was not too big; a minimum size hole was just a little too small for the part to drop through it. I'm not sure how they were used in combination, but I am about to start using them for ScopeRoller rather than measure every part with a micrometer. My thought (and perhaps the way they did it) is to stack the maximum gauge above the minimum gauge with enough room between for the part to slide out between the gauges made of 1/4" aluminum or acetal. If the part falls through maximum gauge but not through the underlying minimum gauge you turn the combination on its side and the part falls out. For ScopeRoller I am going to make the maximum gauge .01" larger than needed, and minimum gauge .01" smaller and hold them together with 4 1/4" bolts at the corner of each gauge. This should give me parts +-.01".