BRASS LOCK NUTS
Brass Lock Nuts for Vibration-Resistant Fastening and Cable Gland Retention
Cable Glands India manufactures brass lock nuts (thin hex nuts, jam nuts and knurled cable gland lock nuts) machined from free-cutting and DZR brass bar to DIN 439, DIN 985, ISO 4035 and IS 10238 dimensions. Brass lock nuts are used to retain cable glands, conduit fittings and threaded hardware against panel and enclosure walls, and to prevent bolted joints loosening under vibration in switchgear, transformers and outdoor electrical installations. Price: US$ 14.50/kilogram (FOB/CIF Indian port, ex-works Mumbai, price subject to size, thread and finish).
Product Overview
A brass lock nut, also called a check nut, jam nut or thin nut, is a reduced-height internally threaded fastener tightened against a second nut, a gland body or a mating component to resist rotation and prevent loosening under vibration or thermal cycling. In cable gland assemblies, the lock nut (also referred to as a check nut) is threaded onto the gland body from inside the enclosure and tightened against the panel wall, clamping the gland securely and completing the IP-rated seal in conjunction with the entry washer.
Cable Glands India manufactures lock nuts in standard hexagon thin-nut profile per DIN 439/ISO 4035, as well as knurled round lock nuts specifically sized to match our brass cable gland thread series (metric, PG and NPT), and serrated-face lock nuts that bite into the panel surface for improved earthing continuity across painted or coated enclosure walls.
Because the locking action of a brass jam nut relies on friction and thread-to-thread contact rather than a deformed or nylon-insert element, these nuts retain their locking performance across a wide temperature range and are not degraded by the elevated ambient temperatures found near transformers, switchgear and outdoor junction boxes, where nylon-insert steel lock nuts would be unsuitable.
Standard free-cutting brass (CuZn39Pb3) lock nuts are supplied for general indoor panel and control-cabinet work. DZR brass (CW602N/CZ132) lock nuts are recommended for outdoor cable entries, marine deck boxes and coastal substations where the nut is exposed to condensation, rain or salt-laden air over the installation lifetime, protecting against selective dezincification of the thread and locking face.
Lock nuts supplied as part of a cable gland kit are dimensionally matched to the gland body thread to guarantee correct engagement depth and consistent clamp load across a production batch, avoiding the fit issues that can occur when a generic hardware-store nut is substituted for the manufacturer-specified component.
Surface finishes include plain brass, nickel plating and tin plating, selected to match the finish of the parent cable gland or fitting for a consistent appearance on visible panel and switchgear installations, and to provide additional corrosion protection where required.
All lock nuts are thread-gauged and dimensionally checked prior to dispatch, with batch traceability maintained back to the raw material heat number, supporting quality documentation required by EPC contractors and utility procurement specifications.
Key Features
- Machined from free-cutting and DZR brass bar to DIN 439, DIN 985, ISO 4035 dimensions
- Reduced-height thin-nut and jam-nut profiles for locking applications
- Knurled and serrated variants for cable gland and panel-earthing retention
- Friction-based locking unaffected by high ambient temperature
- Matched thread series (metric, PG, NPT) to Cable Glands India gland bodies
- Plain, nickel-plated and tin-plated finish options
- 100% thread-gauged and dimensionally inspected before dispatch
- Custom thread and knurl patterns manufactured to customer drawing
Anti-Vibration Thread Locking
Brass lock nuts resist loosening by being tightened against a mating nut or shoulder, creating opposing friction forces along the thread flanks that remain stable under vibration and repeated thermal expansion/contraction cycles. This mechanical locking principle does not rely on an elastomeric or nylon element, so performance is not degraded by heat, oil, or ageing, making brass jam nuts suitable for long-term outdoor and high-temperature electrical installations.
Cable Gland and Conduit Fitting Retention
The most common application for our brass lock nuts is securing cable glands and conduit fittings to the wall of an electrical enclosure. The lock nut is threaded onto the gland body from inside the panel and tightened against the internal face, clamping the gland flange to the external face and, together with the entry washer, completing the IP54-IP68 seal rating of the gland assembly.
Knurled and Serrated Grip Variants
Knurled lock nuts provide a hand-grippable surface for initial hand-tightening before final spanner torque, commonly used on smaller cable gland sizes. Serrated-face lock nuts include radial teeth on the clamping face that bite through paint or oxide layers on the panel surface, improving electrical earthing continuity between the gland body and enclosure, a requirement in many earthing and bonding specifications.
Material Selection for Outdoor Duty
Standard CuZn39Pb3 brass lock nuts are suitable for indoor panels and control cabinets. For outdoor cable entries, coastal substations, marine deck boxes and other high-humidity or saline environments, DZR brass (CW602N/CZ132) lock nuts are recommended to prevent dezincification corrosion of the thread and sealing face over the installation lifetime.
Slim Profile Design
Thin-nut and jam-nut profiles reduce the axial space required behind a panel or gland body compared with a full hex nut, which is important in compact enclosures, meter boxes and instrumentation panels where clearance behind the mounting surface is limited.
Compliance with International Standards
Dimensional compliance is verified against DIN 439, DIN 985, ISO 4035, BS 4190 and IS 10238 as applicable, allowing distributors and EPC contractors to reference Cable Glands India lock nuts directly in tender bills of materials and specification documents.
Technical Specifications
| Parameter | Specification |
|---|---|
| Product type | Hex thin/jam nut, knurled cable gland lock nut, serrated lock nut |
| Thread size range | M12 to M75 metric; PG7 to PG48; 1/2″ to 4″ NPT/BSP (gland-matched sizes) |
| Governing standards | DIN 439, DIN 985, ISO 4035, BS 4190, IS 10238 |
| Thread tolerance class | 6H (internal) as standard |
| Material | CuZn39Pb3, CuZn36Pb3, CW602N/CZ132 (DZR) |
| Manufacturing process | CNC bar turning / hot forging + tapping + knurling/serration |
| Standard finish | Plain brass (natural) |
| Optional finish | Nickel plating, electro-tin plating |
| Height (thin nut) | 0.5-0.8 x nominal thread diameter (per DIN 439) |
| Inspection | Thread gauging (go/no-go), dimensional check, visual surface inspection |
| Packing | Bulk cartons, poly bags; export wooden pallets |
| Price | US$ 14.50/kilogram (FOB/CIF Indian port, MOQ and finish dependent) |
Raw Material Grades
| Grade / UNS | Common Name | Cu % | Zn % | Pb % | Typical Use |
|---|---|---|---|---|---|
| C38500 / CW614N | Free-cutting brass | 57-59 | Bal. | 1.5-2.5 | General purpose lock nuts |
| C36000 | Free-cutting brass | 60-63 | Bal. | 2.5-3.7 | High-speed screw machine nuts |
| CW602N / CZ132 | DZR brass | 58-64 | Bal. | 1.6-2.5 (+As) | Outdoor, marine, coastal cable entries |
| C46400 | Naval brass | 60-62 | Bal. (+Sn ~0.75) | <0.2 | High-strength, seawater exposure |
International Equivalent Standards
| Region / Country | Standard | Description |
|---|---|---|
| Germany (DIN) | DIN 439 / DIN 985 | Hexagon thin nuts / prevailing torque lock nuts |
| International (ISO) | ISO 4035 / ISO 7040 | Hexagon thin nuts / nylon-insert lock nuts |
| United Kingdom (BS) | BS 4190 | ISO metric black hexagon nuts (thin series) |
| India (BIS) | IS 10238 | Hexagon thin nuts, metric series |
| USA (ANSI/ASME) | ASME B18.2.2 | Inch series jam nuts |
| Japan (JIS) | JIS B1181 | Hexagon thin nuts |
Product Types / Variants
| Variant | Description |
|---|---|
| Hex thin nuts / jam nuts | DIN 439 / ISO 4035 profile for general locking duty |
| Knurled cable gland lock nuts | Round knurled profile matched to gland body thread |
| Serrated lock nuts | Toothed clamping face for earthing continuity through paint |
| DZR lock nuts | Dezincification-resistant for outdoor/marine duty |
| Plated lock nuts | Nickel or tin plated to match gland/fitting finish |
| Custom lock nuts | Special threads, heights and knurl patterns to drawing |
Applications in Industry
Brass lock nuts manufactured by Cable Glands India are used for: securing brass, nylon and stainless cable glands to enclosure and panel walls; locking conduit fittings, bushings and adaptors in place; retaining earthing terminals and bonding lugs against vibration loosening; jam-nut locking of threaded rods and studs in switchgear and busbar assemblies; and general panel-building applications requiring a low-profile, corrosion-resistant locking fastener. EPC contractors and panel builders specify brass lock nuts wherever electrical continuity, IP-rated sealing and long-term vibration resistance are required together in a single fastener.
Manufacturing Process
| Step | Process Description |
|---|---|
| 1. Raw material selection | Certified brass bar procured against mill test certificate |
| 2. Forming | CNC bar turning or hot forging to hex/round blank with pre-drilled bore |
| 3. Tapping | Internal thread tapping to 6H tolerance, gland-matched pitch as applicable |
| 4. Knurling / serration | Knurl rolling or serration cutting on outer face/rim as per variant |
| 5. Facing and deburring | Face flat, chamfer and vibratory deburr to remove machining burrs |
| 6. Surface finishing | Plain polish, nickel plating or tin plating as ordered |
| 7. Inspection | Thread gauging, dimensional and visual inspection |
| 8. Packing and dispatch | Bulk carton packing, export documentation, mill certificates issued |
Quality Standards and Certifications
Cable Glands India manufactures brass lock nuts under an ISO 9001 certified quality management system, to DIN 439, DIN 985, ISO 4035, BS 4190 and IS 10238 dimensional standards. Raw brass is sourced against mill test certificates confirming chemical composition. RoHS and REACH compliance documentation is available for plated finishes on request. Salt-spray corrosion testing (ASTM B117) can be arranged on request for DZR and plated batches destined for coastal or marine projects. Please confirm the certification package required for your project at the time of enquiry.
Why Choose Cable Glands India
- Lock nuts dimensionally matched to our own brass cable gland thread series
- In-house tapping, knurling and serration capability for consistent quality
- Standard and DZR brass grades stocked for indoor and outdoor duty
- Custom thread, height and knurl patterns engineered to drawing
- Export packing and documentation for direct container/LCL shipment
- Transparent per-kilogram pricing with no hidden tooling charges on standard sizes
Frequently Asked Questions
What is a brass lock nut used for?
A brass lock nut secures a cable gland, conduit fitting or bolted joint against loosening from vibration, and in cable gland assemblies it clamps the gland body to the enclosure wall to complete the IP-rated seal.
What is the difference between a lock nut and a hex full nut?
A lock nut (thin nut/jam nut) has a reduced thread height compared with a full nut and is typically tightened against a second nut or component to create locking friction, rather than carrying the full proof load alone.
Are brass lock nuts suitable for outdoor use?
Standard brass lock nuts perform well outdoors; for coastal, marine or high-humidity environments, DZR brass grade is recommended to prevent dezincification corrosion over the service life of the installation.
Do brass lock nuts fit any cable gland brand?
Cable Glands India lock nuts are dimensionally matched to our own gland body thread series; for use with third-party glands, please confirm the exact thread designation (metric, PG or NPT) when ordering.
What is a knurled lock nut?
A knurled lock nut has a diamond or straight knurl pattern rolled onto its outer diameter to allow hand-tightening before final spanner torque, commonly used on smaller cable gland and conduit fitting sizes.
What is a serrated lock nut used for?
Serrated lock nuts have radial teeth on the clamping face that bite through paint or oxide layers on the panel, improving earthing/bonding continuity between the fastener and the enclosure.
What certifications are provided?
Mill test certificates are issued as standard. ISO 9001 manufacturing compliance, RoHS/REACH documentation and salt-spray test reports can be provided on request depending on grade and finish.
What is the minimum order quantity?
Standard catalogue sizes are available from small trial quantities; custom threads or knurl patterns may carry a minimum order quantity depending on tooling. Contact our sales team for a quotation.
What is the price of brass lock nuts?
Standard pricing is US$ 14.50 per kilogram (FOB/CIF Indian port), varying with size, brass grade, finish and order quantity.
What is the typical lead time for export orders?
Standard sizes in stock grades typically ship within 2-3 weeks of order confirmation; custom sizes and finishes may require 4-6 weeks including first-article approval.
Equivalent Terms in Other Languages
| Language | Brass Lock Nut | Related Term 1 | Related Term 2 | Related Term 3 |
|---|---|---|---|---|
| Spanish | Contratuerca de latón | Tuerca de fijación | Tuerca delgada de latón | Prensaestopas de latón |
| Russian | Латунная контргайка | Латунная стопорная гайка | Латунная тонкая гайка | Латунный кабельный ввод |
| French | Contre-écrou en laiton | Écrou de blocage en laiton | Écrou mince en laiton | Presse-étoupe en laiton |
| Portuguese | Contraporca de latão | Porca de fixação de latão | Porca fina de latão | Prensa-cabos de latão |
| Italian | Controdado in ottone | Dado di bloccaggio in ottone | Dado sottile in ottone | Pressacavo in ottone |
Related Products and Linked Parts
- Brass Hex Nuts Full Nuts
- Brass Panel Nuts
- Brass Square Nuts
- Brass Flat Head CSK Head Machine Screws
- Brass Washers, Pressed Washers
- Brass Bolts
- Brass Cable Glands
- Brass Fasteners (Category)
Request a Quote
Cable Glands India supplies brass lock nuts worldwide to electrical OEMs, EPC contractors, power utilities and distributors, at US$ 14.50/kilogram (FOB/CIF Indian port). Send your gland/thread size, grade and quantity requirement to sales@cableglandsindia.com or call +91 22 4344 9300 for a formal quotation and sample dispatch.