Precision Components
Heat-set, moulded-in and press-fit inserts for plastic housings
M1 – M6 · Precision Components Overview
Plastic threads are the weakest point of any moulded enclosure. They strip after a handful of service cycles, creep under sustained load and cannot carry real preload. A threaded insert moves the thread into metal, and the plastic only has to hold the insert — a much easier job that can be engineered with a defined pull-out and torque-out strength.
We supply heat-set inserts with a knurled or barbed outer profile, moulded-in inserts with an anti-rotation knurl, ultrasonic inserts and press-fit types. Brass is the default for heat-set because it conducts heat evenly and machines cleanly; stainless is used where corrosion resistance or higher strength is needed. Each insert design is characterised by pull-out force, torque-out and recommended hole diameter in a specified resin.
Thread range
M1 – M6
Types
Heat-set, moulded-in, ultrasonic, press-fit
Outer profile
Knurled, barbed, hex, straight knurl
Materials
C3604 brass, SUS303, SUS316
Insert length
2 – 20 mm
Hole diameter
Matched to insert and resin, ±0.05 mm
Design intent
Six engineering decisions that separate a micro fastener that works from one that merely fits the drawing.
Each insert profile is tested in a reference resin so you can design the boss around a measured pull-out force rather than a rule of thumb.
Knurls, barbs or hex flats resist torque-out, preventing the insert from spinning when the screw is over-tightened.
Installation temperature and time windows are published per resin, so the boss softens enough to accept the insert without stress-cracking.
Inserts placed in the mould eliminate the secondary heat-set operation and give the strongest retention in glass-filled resins.
Flush inserts for cosmetic surfaces, protruding inserts where a standoff function is also needed.
Micro inserts for wearables and earbuds, where the wall section may be only 1.2 mm.
Technical data
Reference data for design and sourcing. For a specific part, the drawing governs — these tables are the starting point for a joint review.
| Thread | Insert Ø (mm) | Insert length (mm) | Hole Ø (mm) | Pull-out (N, ABS) | Boss Ø (mm) |
|---|---|---|---|---|---|
| M1.0 | 2.0 | 2.5 | 1.95 | 180 | 3.2 |
| M1.2 | 2.4 | 3.0 | 2.35 | 230 | 3.6 |
| M1.6 | 3.0 | 4.0 | 2.95 | 380 | 4.5 |
| M2.0 | 3.6 | 5.0 | 3.55 | 520 | 5.4 |
| M2.5 | 4.2 | 6.0 | 4.15 | 750 | 6.3 |
| M3.0 | 5.0 | 7.0 | 4.95 | 1,050 | 7.5 |
| M4.0 | 6.5 | 9.0 | 6.45 | 1,800 | 9.8 |
| M5.0 | 8.0 | 11.0 | 7.95 | 2,800 | 12.0 |
| M6.0 | 9.5 | 13.0 | 9.45 | 4,000 | 14.3 |
Values are typical for the stated material and finish. Actual performance depends on the mating material, engagement length and assembly torque. Confirm with a sample test before design freeze.
Options
Mix these within one part number family. Where a combination is not manufacturable at your tolerance, we will say so at quotation rather than after the first lot.
Where it is used
Representative positions rather than an exhaustive list. Many of our parts are designed for one specific assembly and never appear in a catalogue.
| Assembly | Typical use |
|---|---|
| Notebook and tablet housings | M1.6–M2.0 heat-set inserts in 1.5 mm PC/ABS bosses |
| Wearable and earbud cases | M1.0 micro inserts in thin-wall shells |
| Robot cosmetic covers | M3.0 inserts for repeated removal during service |
| Automotive interior modules | Moulded-in M4.0 inserts in glass-filled PA |
| Medical device enclosures | Closed-end M3.0 inserts for cleanability |
| Industrial control boxes | M5.0 inserts carrying cover and earth bond |
Quality control
Inspection is not a final gate. It is a set of checks placed where a process can actually drift, with the result recorded against the lot code.
01
Insert dimensions, optical comparator
02
Hole diameter recommendation verified by trial install
03
Pull-out force, tensile tester, per lot
04
Torque-out, torque tester
05
Installation temperature profile, thermal camera
06
Boss crack inspection after installation
07
Thread gauge, GO / NO-GO
08
Plating thickness where specified
Questions
The questions our engineers answer most often on this product family.
Related products
These families are frequently used in the same assembly, or as an alternative when the joint requirement changes.
Micro Screws · M0.5 – M6
Precision machine screws from M0.5 to M6 with rolled Class 6g threads, tight head concentricity and clean drive recesses for automated driving.
Precision Components · M1 – M4
Male-female and female-female standoffs from M1 to M4, plus plain spacers, in brass, stainless and aluminium — with length tolerances that keep board stacks parallel.
Micro Screws · M0.6 – M4
Self-tapping micro screws from M0.6 to M4 with controlled point geometry, engineered to form clean threads in engineering plastics without cracking the boss.
Specialties · 0.05 – 1.5 mm strip
Progressive-die stamped parts from 0.05 to 1.5 mm strip — contacts, spring clips, EMI shields and mounting brackets produced alongside our screw lines.
Send a drawing or 3D model with the mating material and finish requirement. We reply with a process route, tolerance review and price — usually within two working days.