Description
Brass Half Nut (Thin Hex Lock Nut) 3/8″ x 24 UNF for Brake and Hydraulic Fittings
Solid brass thin hex half nut, 3/8″ x 24 UNF, for locking bulkhead unions and brake fittings to panels or brackets. Supplied by EMS Spares, Leicester.
Specification
| Thread | 3/8″ x 24 UNF |
|---|---|
| Type | Thin hex half nut / lock nut |
| Hex / spanner size | N/A |
| Thickness | N/A |
| Material / finish | Solid brass, natural finish |
| Weight | 4.5g approx each |
| Interchange reference | LNB1* |
| EMS part number | EMS-ALNB1 |
* Reference numbers are for identification only. All dimensions are approximate.
Buyer’s guide: brass half nuts (lock nuts)
A half nut is a thin hex nut used to lock a bulkhead union, T-piece or fitting to a panel or bracket, or as a jam nut. Brass is used so it will not rust or seize. Match the thread to your fitting: this nut is 3/8″ x 24 UNF.
Identify your thread
| Thread | Outside diameter (male thread) | Threads | Typically found on |
|---|---|---|---|
| 3/8″ x 24 UNF | 9.5mm approx | 24 per inch | Most British classic car brake circuits on 3/16″ pipe |
| 7/16″ x 20 UNF | 11.1mm approx | 20 per inch | British classics, Land Rover, commercial vehicles – master cylinders, clutch and 1/4″ pipe circuits |
| M10 x 1mm | 10mm approx | 1mm pitch (about 25 per inch) | Most European and later cars |
| 3/8″ x 20 BSF | 9.5mm approx | 20 per inch | Older British cars (often pre-1960s) |
Tip: 3/8″ UNF and M10 x 1 look almost the same and will start to screw in, then bind. Never force a fitting. Measure the male thread diameter or use a thread gauge, or compare against your old part.
How to fit – good practice
- Check the thread before fitting – compare with your old part or use a thread gauge.
- Start every thread by hand for several turns – it should turn freely. If it binds, stop and check.
- Tighten with correctly sized split (flare nut) spanners. Brass is softer than steel – firm, not excessive.
- Bleed the system, then check every joint for leaks with the pedal pressed hard.
Safety: brakes and clutches are safety-critical systems. If you are not confident, have the work done or checked by a qualified mechanic.
Pack sizes
5 or 10 nuts.
Delivery
Free UK delivery on every order (including Northern Ireland, Highlands & Islands). Same-day dispatch on orders placed before 10am.
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FAQ
Does it fit the EMS bulkhead unions? Yes – choose the same thread as your bulkhead union.
Need help? Message us with your fitting.
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