Machine Screw Nuts, UNC (Hex and Square) are selected when an assembly calls for small inch hex and square nuts for numbered machine screw sizes, UNC thread. This application guide to the ASME B18.2.2 type covers concrete end-uses, the specification checklist, correct installation, and where an alternative fastener performs better. Stocked across roughly 1 to 12, they cover general to heavy-duty work.
Typical Applications for Machine Screw Nuts, UNC (Hex and Square)
The most common settings where these are specified:
- Electronics: small inch screws.
- Electrical: terminals.
- Hobby: models.
- Instrumentation: panels.
How to Specify Machine Screw Nuts, UNC (Hex and Square) for Your Application
- Size: Match the nominal size to the mating thread or hole. This product spans 1–12; check the full table below for the exact dimensions of each size.
- Locking & grade: Match the strength grade to the bolt, and choose a locking style (nyloc, all-metal, serrated flange) if the joint sees vibration.
- Environment: For damp, coastal or chemical exposure prefer A4/316 stainless or a suitable coating; indoors, plated steel or A2 is usually sufficient.
- Standard: This product is supplied to ASME B18.2.2. Quoting the standard on your order guarantees interchangeable dimensions between suppliers.
Installation & Assembly Practice
- Run the nut down by hand before applying the wrench to catch cross-threading early.
- Tighten the nut rather than the bolt head where access allows — the torque-to-preload relation is more consistent.
- For locking styles, note that nyloc inserts are single-use in critical joints and lose grip above roughly 120 °C.
Common Selection Mistakes with Machine Screw Nuts, UNC (Hex and Square)
- Pairing a high-class bolt with a lower-class nut — the nut strips before the bolt reaches proof load; the nut class must meet or exceed the bolt class.
- Using a plain nut with a spring washer in severe vibration instead of a prevailing-torque locking nut.
- Re-using nyloc nuts in critical joints.
Where Machine Screw Nuts, UNC (Hex and Square) Are Not the Right Choice
Not on their own — they need a matching bolt or stud — and a plain nut is not a substitute for a locking type under heavy vibration.
Custom manufacturing · Made to drawing
Need a machine screw nuts, UNC (hex and square) outside the standard range?
Locking method is specifiable independently of the rest: nylon insert, all-metal deformed thread, serrated flange, or none. Made by cold heading or tapping.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
