This is an area of gage making that takes something simple like a go/nogo plain plug gage and adds another feature for another check, such as hole depth. It can be a good cost saving idea; after all, the plug gage is already in the hole so a quick glance by the gage user enables this feature to be checked. But sometimes user expectations will not be realized because the feature and the gage to be modified to handle them are unrealistic or one cannot support the other. The following comments may help you avoid these pitfalls.
The first thing you have to determine is whether the plug gage member is long enough to contain depth steps, flats, notches or whatever mod you need for the depth involved. Sounds obvious I know, but we quite often get orders for go/nogo plugs that are not long enough to accommodate the required depth steps. Check your gage supplier’s catalog for the standard length of the Go gage member since that is the only one you can put them on. Some folks overlook this and ask us to put a flat for the Go length on the Go diameter and the flat for the Nogo length on the Nogo diameter member. Some diplomacy is required when we advise them that both have to go on the Go member since the Nogo member usually should not be going in the hole.