

PreciSert Heavy Duty 5/16-18 Non-Locking
PreciSert Heavy Duty 5/16-18 non-locking key-locking insert, part no. MSS1831-103, stainless steel to MIL-I-45914 military standard, external thread 1/2-13, shear engagement 3588in, installation tool HDS-5.
| Features | Military-spec high-load key-locked anti-rotation |
|---|---|
| Thread Diameter | 5/16-18 |
| Thread Standard | Inch unified thread |
| Material | Stainless steel (300 series) |
| Finish | Passivated |
| Environmental Compliance | REACH and RoHS compliant |
| Military Standard | MIL-I-45914 Rev A |
Overview
PreciSert heavy-duty inserts are key-locking inserts built to a tighter dimensional envelope than general-purpose types, and the range includes variants referenced to military standards. The design intent is a repairable, rotation-locked thread where both the installed height and the radial position have to be predictable, as on aerospace and instrument assemblies where a protruding or skewed insert would interfere with mating hardware. This listing: thread 5/16-18, standard Inch unified thread, material Stainless steel (300 series), finish Passivated, military standard MIL-I-45914 Rev A.
Advantages
Military-standard referenced variants give a documented material and finish baseline, which shortens qualification when the assembly itself has to meet a defence or aerospace specification.
The solid body carries load through its full length rather than through a coil, so pull-out strength is limited by the parent material rather than by the insert.
Tighter tolerances on insert length and shoulder position mean the installed thread sits at a known depth, so a mating part designed to a fixed stack height does not need shimming.
Key locking works in both directions, so the insert resists rotation during screw installation and during screw removal, which is where a bonded insert typically fails first.
Applications
Aerospace instrument housings, defence electronics enclosures, avionics rack hardware, precision optical bench assemblies, and test equipment where installed height tolerance affects alignment.
When a military standard is quoted, confirm which revision applies — material and finish requirements have changed between revisions, and a certificate to the wrong revision will not be accepted at incoming inspection.
Product information is supplied by Toprecision. Custom parts can be produced to drawing — contact us for samples or a quotation.
Specifications across this series
84 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 Military-spec high-load key-locked, Thread Diameter 5/16-18, Thread Standard Inch unified thread, Material Stainless steel (300 series).
What material and finish is it supplied in?
Stainless steel (300 series); Passivated.
What should I verify before ordering or installing it?
When a military standard is quoted, confirm which revision applies — material and finish requirements have changed between revisions, and a certificate to the wrong revision will not be accepted at incoming inspection.