Helicoil Gauges

HeliCoil gauges are available as Go/No Go thread plug gauges for inspection of tapped holes prior to HeliCoil fitments. The gauges are available in 5H & 6H class for Metric sizes and 2B/3B for UNC/UNF sizes.

Accuracy of the finished thread when the insert is installed is dependent upon the accuracy of the tapped hole. If the finished tapped hole gauges satisfactorily, the installed insert will be within the thread tolerance.

It is not necessary to gauge the installed insert. After the insert is installed, the GO thread plug gauge may not enter freely; however, the insert will always seat itself when the bolt or screw is installed and tightened. (Reference NASM33537).

Gauge handles and all gage nibs are marked with the extreme product limits for the particular size and class of fit. When gauging tapped holes which have been thoroughly cleaned or which have a protective finish applied, the gauge should always be lubricated with light oil. HI nib may enter provided a definite drag results on or before 3rd turn from entry Ref. FEDSTD-H28, Screw thread Standards for Federal Services. Working gauges provide a guaranteed minimum wear allowance on the pitch diameter of the GO members of two ten thousandths of an inch (.0002).

These gauges are recommended for production in sizes 1/2 inch and smaller. Reference gauges have pitch diameters on or close to minimum (basic size). They are essentially laboratory or master gauges .