Brass lock nuts and brass cable gland nuts are precision-machined fastening components critical to the secure installation of cable glands, conduit fittings, and electrical enclosures. At Cable Glands India, we are specialist manufacturers of brass lock nuts in all thread types, sizes, and configurations — widely exported to the USA, UK, Germany, Australia, and the Middle East. Our brass cable gland lock nuts provide the mechanical retention and IP-rated sealing that electrical installations demand.

What Are Brass Lock Nuts?

Brass lock nuts are hexagonal or round-form nuts machined from brass bar stock, designed to be threaded onto the body of a cable gland, conduit fitting, or pipe fitting and tightened against the panel or enclosure wall to lock the fitting in place. They resist loosening due to vibration, thermal cycling, and mechanical stress. In cable gland assemblies, the lock nut provides IP sealing when used with appropriate sealing washers.

Types of Brass Lock Nuts We Manufacture

1. Metric Cable Gland Lock Nuts (M12 to M63)

Standard metric cable gland lock nuts in M12×1.5, M16×1.5, M20×1.5, M25×1.5, M32×1.5, M40×1.5, M50×1.5, and M63×1.5 — the most common sizes used worldwide. Manufactured per DIN 46320 and IEC 62444 standards. Available in bare brass, nickel-plated, and chrome-plated finishes.

2. PG Thread Lock Nuts (PG7 to PG48)

PG (Panzergewinde / conduit thread) lock nuts for European-style cable glands used widely in industrial control panels, junction boxes, and electrical enclosures. Sizes: PG7, PG9, PG11, PG13.5, PG16, PG21, PG29, PG36, PG42, and PG48.

3. NPT Conduit Lock Nuts (for USA Market)

NPT (National Pipe Taper) threaded brass lock nuts in 1/2″ NPT, 3/4″ NPT, 1″ NPT, 1-1/4″ NPT, 1-1/2″ NPT, and 2″ NPT — compliant with UL 514B, NEMA FB1, and ANSI/NFPA 70 (NEC) requirements for conduit fittings in US electrical installations.

4. BSP / BSPP Thread Lock Nuts (G1/4 to G2)

British Standard Pipe (BSP/BSPP) brass lock nuts in G1/4″, G3/8″, G1/2″, G3/4″, G1″, G1-1/4″, G1-1/2″, and G2″ for UK, Australian, and Commonwealth market cable glands and pipe fittings.

5. Hexagonal Brass Lock Nuts (DIN 934 / ISO 4032)

Standard hex nuts in metric (M3 to M80) and unified (UNC/UNF, #4-40 to 3/4″-10) thread forms for general fastening applications. Manufactured to DIN 934, ISO 4032, ASME B18.2.2, and BS 1083 standards.

6. Nyloc (Nylon Insert) Brass Lock Nuts

Brass hex nuts with a nylon insert collar that grips the bolt thread to provide vibration-resistant locking without a separate lock washer. DIN 985 / ISO 7042 compliant. Available M3 to M30 in brass.

7. Thin / Jam Lock Nuts (DIN 439 / ISO 4035)

Low-profile (reduced height) brass lock nuts used as jam nuts to lock standard nuts against loosening. Height approximately 0.5× standard nut height. Available M3 to M64.

8. Brass Earth Tag / Earth Terminal Lock Nuts

Special lock nuts with integrated earth tag (grounding lug) to provide electrical continuity between cable gland body, enclosure panel, and earth cable — essential for EMC and electrical safety compliance.

Related Products

• Brass Cable Gland Bodies (Metric, PG, NPT, BSP)
• Brass Sealing Plugs and Blanking Plugs
• Brass Reducer Adaptors and Extensions
• Neoprene / EPDM Sealing Washers
• Brass Anti-Vibration Lock Nuts
• Brass Conduit Couplings and Connectors
• Brass Hex Bolts, Screws, and Studs
• Brass Dome Nuts (Acorn / Cap Nuts)

Material Grades & International Equivalents

Standard	Grade	Cu%	Zn%	Pb%	Notes
EN (Europe)	CW614N	57–59	Bal.	2.5–3.5	Free-machining, most common for lock nuts
BS (UK)	CZ121	57–59	Bal.	2.5–3.5	UK equivalent of CW614N
ASTM (USA)	C36000	60–63	Bal.	2.5–3.7	US free-cutting brass
EN (DZR)	CW617N	57–59	Bal.	1.6–2.5	Dezincification-resistant (water service)
DIN (Germany)	Ms58 / 2.0401	57–59	Bal.	2.5–3.5	German standard
JIS (Japan)	C3601	59–63	Bal.	1.8–3.7	Japanese standard

Standards and Dimensions for Cable Gland Lock Nuts

Thread Size	Thread Pitch (mm)	Width Across Flats (mm)	Height (mm)	Typical Cable OD Range
M12	1.5	20	6	3–7 mm
M16	1.5	24	7	4–10 mm
M20	1.5	30	8	6–14 mm
M25	1.5	36	9	10–18 mm
M32	1.5	46	10	14–25 mm
M40	1.5	55	12	19–31 mm
M50	1.5	68	13	26–40 mm
M63	1.5	85	15	34–55 mm

Why Choose Cable Glands India for Brass Lock Nuts?

• Jamnagar Expertise: Jamnagar (India) is the world’s largest brass machining cluster — access to best-quality CZ121/CW614N brass and expert machining at competitive prices.
• All Thread Standards: Metric, PG, NPT, BSP, UNC, UNF — all thread forms machined to precise standards with calibrated go/no-go gauges.
• Surface Finishing: Bright brass, nickel-plated (5–15 µm), chrome-plated, hot-dip tin, and special finishes available.
• High Volume: Capacity for 10 million+ lock nuts per month across all sizes.
• Customization: Special sizes, special materials (SS316, aluminium), knurled bodies, and custom markings available.
• Quality: ISO 9001:2015; 100% thread gauging; hardness testing; dimensional inspection with CMM.

Frequently Asked Questions – Brass Lock Nuts

Q1: What is the purpose of a cable gland lock nut?

A: A cable gland lock nut is tightened onto the threaded shank of the cable gland body after it is inserted through an enclosure panel knockout. It clamps the cable gland securely against the panel, provides mechanical retention, and (with a sealing washer) contributes to the IP rating of the entry point.

Q2: What is the difference between metric and PG thread lock nuts?

A: Metric (ISO) cable gland threads use standard metric pitch (e.g., M20×1.5) and are used worldwide. PG (Panzergewinde) threads are a German DIN standard (DIN 40430) with specific thread forms (e.g., PG 16 = 22.5mm OD) used primarily in older European industrial equipment. Both use the same hexagonal lock nut concept but have different thread geometries.

Q3: What size lock nut do I need for an M20 cable gland?

A: An M20 cable gland requires an M20×1.5 lock nut. The width across flats (spanner size) is typically 30mm for standard cable gland lock nuts per DIN 46320. The nut height is approximately 8mm. Check your cable gland manufacturer’s datasheet for exact dimensions.

Q4: Are brass lock nuts RoHS compliant?

A: Standard CW614N/CZ121 brass lock nuts contain lead (2.5–3.5%) and are therefore NOT fully RoHS compliant for all applications. However, they are exempt from RoHS restrictions in industrial electrical and electronic equipment categories under RoHS Directive 2011/65/EU Annex III. For lead-free requirements, we offer silicon brass (C87850) or low-lead brass alternatives.

Q5: What torque should I apply to a brass cable gland lock nut?

A: Recommended tightening torque for M20 cable gland lock nut on 2mm steel panel: 15–20 Nm. Torque increases with nut size (M25: 25–35 Nm, M32: 35–50 Nm). Over-tightening can crack enclosure panels or strip threads — always use calibrated torque wrench for IEC 60079 (Ex) applications.

Q6: Do you supply brass lock nuts with sealing washers?

A: Yes. We supply lock nuts with matching sealing washers (neoprene, EPDM, or fibre) as sets. The combination of lock nut + sealing washer + cable gland body achieves IP66/IP68 ratings per IEC 60529 when properly installed.

Q7: Can brass lock nuts be used outdoors?

A: Yes. Nickel-plated or chrome-plated brass lock nuts are suitable for outdoor use. For harsh marine or chemical environments, consider stainless steel (SS316) lock nuts or hot-dip tin-plated brass for maximum corrosion protection.

Q8: What is the thread pitch of M20 cable gland lock nuts?

A: M20 cable gland lock nuts use a pitch of 1.5mm (M20×1.5 fine thread) — finer than the standard M20×2.5 coarse thread. The 1.5mm pitch is specified in IEC 62444 and DIN 46320 for cable gland fittings to prevent loosening.

Q9: Do you supply NPT brass lock nuts for the US conduit market?

A: Yes. We manufacture and supply NPT threaded brass lock nuts in 1/2″ to 2″ NPT sizes per ASME B1.20.1. These conform to UL 514B and are used with NPT conduit connectors, cable glands, and liquidtight conduit fittings in the US market.

Q10: What material should I choose for brass lock nuts in corrosive environments?

A: For mildly corrosive environments: nickel-plated brass. For marine/offshore: stainless steel SS316 lock nuts. For chemical plants with acid exposure: PTFE-coated brass or SS316. For food/pharma: SS316L polished lock nuts.

Q11: What is the minimum order quantity for brass lock nuts?

A: MOQ: 1,000 pieces for standard sizes in standard finish. 500 pieces for nickel-plated. Custom sizes and special finishes: 500 pieces minimum. Sample orders (50–100 pieces) available for approval testing at standard price.

Q12: Can I get a custom size brass lock nut not listed in your standard range?

A: Yes. We manufacture custom brass lock nuts in any thread form, width across flats, nut height, or special features (knurled OD, slotted face, anti-rotation tabs). Provide a drawing or sample, and we will quote within 24 hours.

Q13: How are brass lock nuts finished and what finishes do you offer?

A: Bright machined (natural brass), barrel tumbled, electroless nickel (5–10µm), electrolytic nickel, chrome plating, hot-dip tin, rack-plated silver, and zinc plating. RoHS-compliant trivalent chromate passivation also available.

Order brass lock nuts and cable gland nuts from Cable Glands India. Email sales@cableglandsindia.com with your size, thread type, quantity, and finish requirements.

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