Oversize Inserts:

Oversize Inserts are Inserts with a larger wire cross section.

Oversize Inserts are used to correct the tapping errors that cause STI* assemblies to gage oversize. They can also be used to correct conditions of slight taper and bell-mouth in STI tapped holes.

Oversize Insert Kits and components come in inch sizes UNC and UNF, and Metric sizes as shown in the following tables. When Oversize Inserts are installed, the original internal thread size is re-established allowing installation of the original size bolt. The columns on the right of Tables A & C indicate the effective correction to the pitch diameter of oversize tapped holes.

Each kit contains the quantity of 1-1/2 diameter inserts indicated in Tables A and C and a special oversize bot-toming tap. For identification, the tang and bottom coil are dyed yellow on all Oversize Inserts.

HOW TO INSTALL

1. Retap the oversize hole with the special bot-toming tap furnished in the kit. No redrilling is necessary. For critical applications, refer to the tapping and gaging procedure listed in the Engineering Data and Trouble Shooting section.

2. Install the insert to the proper depth below the top surface (1/4 to 1/2 pitch for tapped holes without a countersink and 1 to 1-1/2 pitch for holes with a countersink). Use the same tool recommended for a standard Heli-Coil Insert of the same size.

3. If the assembly is still oversize, it will be necessary to resort to a Twinsert Repair Kit as shown on pages 6 & 7. Note – a standard gage can be used to check an installed free-running Oversize Insert assembly provided the insert is fully seated.

4. When assembly is satisfactory, remove the tang with the tang break-off tool recommended for the original insert.