Topsert Thin-Wall 3/8-16 Carbon Steel

Overview

A thin-wall Topsert insert maximises the internal thread size for a given outside diameter, which is the constraint when a boss is already fixed by the surrounding design. The wall between internal and external thread is reduced to the minimum that still carries the specified load, so the insert fits where a standard heavy-duty part would break through the boss wall. This listing: thread 3/8-16, standard Inch unified thread, material Carbon steel (C1215 or equivalent), finish Zinc phosphating + Ferrocote 364-3 oil.

Advantages

Reduced outside diameter lowers the installation torque needed, which matters when the parent material is a thin-wall die casting that would otherwise crack.

Load is carried by the external thread over the full insert length, so pull-out strength remains governed by the parent material rather than by the insert wall.

The larger internal thread in the same hole lets a bigger screw be used without redesigning the boss, often the difference between repairing a housing and replacing it.

Key locking is retained despite the reduced wall, so the insert does not spin during screw installation — the usual failure of thin-walled friction-fit bushings.

Applications

Thin-wall die-cast housings, electronics enclosures with moulded bosses, instrument cases where wall thickness is set by styling rather than structure, and repair of castings whose boss diameter cannot be increased.

Thin-wall inserts trade radial strength for size. Do not use them where the joint sees transverse load or repeated removal — the wall will ovalise and the insert will loosen. Check minimum boss wall before ordering.

Product information is supplied by Toprecision. Custom parts can be produced to drawing — contact us for samples or a quotation.