Topsert Heavy Duty 1 1/2-6 Carbon Steel

Overview

A Topsert heavy-duty insert is a key-locked threaded insert installed into a drilled hole and locked against rotation by driving keys down through the insert body into the parent material. Unlike a wire coil, it provides a solid, repairable thread with a defined shoulder, and the keys positively prevent the rotation that would otherwise occur when the screw is tightened or a damaged thread is being cut. This listing: thread 1-1/2-6, standard Inch unified thread, material Carbon steel (C1215 or equivalent), finish Zinc phosphating + Ferrocote 364-3 oil, features Key-locked anti-rotation.

Advantages

A defined shoulder lets the insert be installed flush or slightly below the surface, giving a controlled bearing face for the mating part rather than relying on the thread alone.

Carbon steel with zinc phosphating plus a Ferrocote oil film gives a stable friction coefficient for installation and reasonable corrosion protection in indoor machinery, without the hydrogen-embrittlement risk of electroplating on high-strength parts.

The insert can be removed and replaced when the internal thread wears out, so a costly casting does not have to be scrapped because of one damaged thread.

The locking keys eliminate rotation, which is the standard failure of a plain press-fit or bonded insert under torque. The insert stays fixed while the screw turns, so the joint can be serviced indefinitely.

Applications

Machine tool bodies, hydraulic manifold blocks, die-cast transmission housings, pump casings, and any casting where a thread will be opened repeatedly over the equipment life or where the parent alloy is too soft to hold a plain thread.

Hole diameter and key depth are both critical: an undersized hole prevents the keys from driving, an oversized one lets the insert spin. State the parent material when ordering, because the same insert needs different hole tolerances in aluminium and in cast iron.

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