NOTE 1.The thread form of Parts NR440004, NR832006 and NI832006 is designed to accept either a machine screw or Type F tapping screw of the thread size designated. Each of the other parts accommodates a tapping screw of the size indicated.

NOTE 2.For maximum screw pull-out resistance with Design 1 parts, the boss I.D. should be as specified above to provide an interference fit with the screw. On-sert fasteners can also be used where the screw clears the I.D. of the boss, but this arrangement reduces resistance to screw pull-out.

NOTE 3.Design 2 parts should always be installed with teh appropriate applicator tool which is designed to protect the projecting thread form from deformation by pressure or a direct blow. Although Design 1 parts may be installed by tapping directly on the top of the fasteners with a hammer, the magnetized applicator tool facilitates handling and positioning.

These distinctive fasteners with a single helical thread slip over hollow plastic bosses and prevent splitting when screws are driven. They also prevent cross-threading and resist screw pull-out. Yet screws may be removed without harming the fasteners or the boss. On-sert fasteners thus perform the same function as solid inserts but cost only about one-fifth as much. One type is used when screws enter the top of a boss while another type is used when screws enter the bottom of the boss.