Topsert Heavy Duty M24-3 Stainless Steel
Topsert Heavy Duty M24-3 stainless steel key-locking insert, part no. 75247, external thread M33-2, length 33.0 mm, installation tool 71242. Key-locked against rotation in a single operation; suitable for thread repair and reinforcement in aluminium and other light alloys. Volume pricing is negotiable.
| Features | Key-locked anti-rotation |
|---|---|
| Thread Diameter | M24-3 |
| Thread Standard | Metric ISO thread |
| Material | Stainless steel (303) |
| Finish | Passivated |
| Environmental Compliance | REACH and RoHS compliant |
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 M24-3, standard Metric ISO thread, material Stainless steel (303), finish Passivated, features Key-locked anti-rotation.
What sets this listing apart: Thread Diameter M24-3 — the largest size in the series (series runs 1-1/2-12 to M24-3).
Advantages
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.
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.
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.
Specifications across this series
91 parts in this series
Values are taken from each part’s own attribute set. Changing length, material or finish changes pull-out strength and installation torque, so compare the row that matches your drawing.
Selection and test data: engagement length, standards, salt-spray hours
FAQ
What are the key dimensions of this part?
Features Key-locked anti-rotation, Thread Diameter M24-3, Thread Standard Metric ISO thread, Material Stainless steel (303).
What material and finish is it supplied in?
Stainless steel (303); Passivated.
What should I verify before ordering or installing it?
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.