A hardened gauge set to the two limits of a feature: the GO end, at the maximum material size, must enter or pass over the part, and the NO GO end, at the other limit, must not. Plug gauges and pin gauges check holes, ring and snap gauges check shafts. Go/no-go checks are fast and need no reading, which makes them the standard on production floors.
Go end drops in, no-go end won't start, that hole's good, now run the go/no-go gauge through the other twelve.
Never force a go gauge; if it needs a push, either the part is tight or the gauge is about to get stuck in it.
Also heard as
- go/no-go
- limit gauge
Related terms
Tolerance
The total amount a dimension is allowed to vary from nominal and still be a good part.
Nominal
The stated target size of a feature before any tolerance is applied.
First article
The first good part off a new setup or program, fully inspected before the rest of the run is made.
Jo blocks
Shop name for gauge blocks: lapped steel or ceramic blocks, accurate to millionths, stacked to make any length.