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Nuts · BSW 1083
BSW 1083 Hex Nut
Accurate Fastners manufactures and supplies BSW 1083 Hex Nuts in stainless steel grades SS 202, SS 304 and SS 316, cold forged to British Standard Whitworth thread form. Available from 1/4" to 3/4" diameter, these nuts are suited to assemblies where BSW-threaded fasteners are specified.
- Standard
- BSW 1083
- Grades
- 304 / 316 / 202
- Size
- 1/4" – 3/4"
- Length
- —
Verification note: Brochure prints the size range as 1.4" – 3.4"; shown here as 1/4" – 3/4" in line with the BSW 1083 hex bolt range. Please confirm.
Overview
What is the BSW 1083 Hex Nut?
The BSW 1083 Hex Nut is a standard hexagonal nut produced to the British Standard Whitworth (BSW) thread specification. BSW is one of the older unified thread standards, characterised by its rounded crests and roots and a 55-degree thread angle, which distinguishes it from the 60-degree profile found in metric and Unified threads. Accurate Fastners supplies these nuts in stainless steel to serve industries that retain BSW-threaded equipment or components.
Each nut in this range is cold forged, a process in which stainless steel bar stock is shaped under compressive force at ambient temperature rather than by cutting or casting. Cold forging generally refines the grain structure of the material and produces consistent dimensional accuracy across a production run. The external hex drive format allows the nut to be engaged with standard open-ended, ring or socket spanners, making it compatible with widely available tooling on site or in a workshop.
The internal thread conforms to the BSW profile, meaning the nut is intended to mate with bolts, studs or threaded rods cut to the same standard. The size range covered — 1/4" to 3/4" diameter — spans a common portion of the BSW range used in light to medium structural and mechanical assemblies. Accurate Fastners applies quality checks during both procurement of raw materials and at the delivery stage, aiming to ensure thread conformity and dimensional consistency across supplied batches.
In Depth
Product description
Construction and Geometry
The BSW 1083 Hex Nut features a six-sided external profile that provides multiple engagement flats for torquing. Cold forging produces a nut body with a consistent bearing face and chamfered lead-in, supporting flush seating against the mating surface. The hexagonal geometry follows the dimensions prescribed under the BSW 1083 standard, governing across-flat dimensions and nut height relative to the nominal thread diameter.
Internally, the nut carries a BSW thread form with a 55-degree included angle and proportionally rounded crests and roots. This geometry differs from sharper-profiled threads and may offer a degree of tolerance to minor surface contamination when mating parts are assembled. All three available stainless steel grades — SS 202, SS 304 and SS 316 — are processed through the same cold-forging route, with grade selection influencing corrosion performance rather than the geometric outcome.
Functional Behaviour in an Assembly
When tightened onto a BSW-threaded bolt or stud, the hex nut develops clamping load by converting applied torque into axial tension within the fastener pair. The bearing face transmits compressive force to the joint interface, while the thread flanks carry the load transfer between nut and bolt. Correct engagement requires that the mating bolt also conforms to the BSW thread standard; mixing thread profiles risks cross-threading and unreliable clamping.
Stainless steel hex nuts, in general, can be susceptible to galling during installation — a condition where thread surfaces seize under friction. Using an appropriate anti-seize compound or lubricant during assembly is commonly recommended practice for stainless fasteners. Ensuring the correct spanner size is used across the hex flats helps maintain torque accuracy and avoids rounding of the nut, which could complicate future removal or inspection.
How It Differs from Similar Fasteners
The primary distinction of a BSW hex nut from metric hex nuts lies in the thread form and pitch system. BSW uses imperial diameter sizing with threads per inch rather than a millimetre pitch, and the 55-degree flank angle means BSW and metric nuts are not interchangeable even where nominal diameters appear similar. Engineers specifying replacements for existing BSW-threaded equipment must confirm thread standard before ordering to avoid incompatibility.
Compared with a flange nut, the standard hex nut lacks an integral bearing washer and may therefore require a separate flat washer under the bearing face where load distribution across a softer substrate is needed. Compared with a heavy hex nut, the BSW 1083 nut typically has narrower across-flat dimensions and a lower profile, making it appropriate where clearance is limited. Buyers should confirm which nut height series is required when enquiring.
Material & Grade
Material and grade information
- SS 304
- SS 316
- SS 202
BSW 1083 Hex Nuts from Accurate Fastners are available in three stainless steel grades. SS 304, an austenitic grade containing approximately 18% chromium and 8% nickel, is among the most widely used stainless alloys and is commonly chosen for general-purpose indoor or mildly exposed environments. SS 202 is a lower-nickel austenitic grade that may offer a cost consideration in applications where the elevated nickel content of SS 304 is not required, though its corrosion resistance is generally considered lower.
SS 316 incorporates molybdenum in addition to chromium and nickel, which typically improves resistance to chloride-containing environments compared with SS 304. It is commonly specified in food processing, pharmaceutical or coastal-adjacent installations where greater corrosion resistance is sought. Buyers are advised to assess the specific service environment, including exposure to chemicals, moisture and temperature, when selecting between these three grades. The Accurate Fastners sales team can assist in confirming grade availability against a specific enquiry.
Grades shown are those documented for this product in the Accurate Fastners brochure. General material notes are guidance only; confirm grade selection for your environment.
Technical Data
Technical specifications
| Product type | Nut – BSW 1083 Hex Nut |
|---|---|
| Material | Stainless steel |
| Material grade | SS 304, SS 316, SS 202 |
| Applicable standard | BSW 1083 |
| Nominal diameter / size | 1/4" – 3/4" |
| Thread type | BSW (British Standard Whitworth) internal thread |
| Head / form | Hexagon |
| Drive / tightening | External hex |
| Manufacturing process | Cold forged |
Sizes
Available sizes
Documented size range
1/4" – 3/4"
Documented length range
Not applicable
Individual sizes within the documented range, thread pitches and lengths are confirmed at quotation stage.
Applications
Industrial applications
Water Treatment Equipment
BSW 1083 Hex Nuts in SS 304 or SS 316 may be suitable for fastening components in RO water purifier assemblies where moisture exposure and thread compatibility with existing BSW-threaded hardware are considerations.
Submersible Pump Assembly
Submersible pump casings and motor housings sometimes retain BSW-threaded fixings. Stainless steel hex nuts in this standard may be used where corrosion resistance in wet environments is a selection factor.
Solar Energy Mounting Structures
Panel mounting frames and racking systems in solar installations may incorporate BSW-threaded fasteners. SS 304 or SS 316 hex nuts can be considered where prolonged outdoor exposure and structural integrity of the fixing are relevant.
Food and Beverage Processing Machinery
SS 316 BSW hex nuts may be considered for machinery panels and guards in food-grade environments where resistance to cleaning agents and hygienic surface standards form part of the equipment specification.
Pharmaceutical and LED Lighting Equipment
Enclosures and frames in pharmaceutical machinery or LED lighting fixtures that carry BSW-threaded fixings may utilise these hex nuts where stainless steel material and standard thread compatibility are both specified requirements.
Features & Selection
Features and selection considerations
Design features
Cold-Forged Construction
The cold-forging process shapes each nut without heat, which may refine grain structure and support dimensional consistency across a production batch compared with cut or cast alternatives.
BSW Internal Thread
The 55-degree British Standard Whitworth internal thread is machined to mate accurately with BSW-profile bolts and studs, making these nuts relevant for legacy or BSW-specified assemblies.
Hexagonal External Drive
Six engagement flats allow the nut to be tightened with standard open-end, ring or socket spanners across the full 1/4" to 3/4" size range without specialist tooling.
Three Stainless Steel Grades
Availability in SS 202, SS 304 and SS 316 allows buyers to select material corrosion performance appropriate to their service environment and project budget considerations.
Quality Checks at Procurement and Delivery
Accurate Fastners' quality control team performs checks at raw material procurement and prior to delivery, supporting batch consistency and thread-form conformance across supplied quantities.
Before you order
Confirm Thread Standard Compatibility
Verify that the mating bolt, stud or threaded rod is also BSW-profiled before ordering. BSW and metric threads are not interchangeable; mixed thread standards risk assembly failure and thread damage.
Select Grade for Service Environment
Choose SS 202 for cost-sensitive, low-exposure duties; SS 304 for general indoor or mild outdoor use; and SS 316 where chloride exposure, cleaning chemicals or higher corrosion resistance is a requirement.
Specify Nominal Diameter and Quantity
State the required nominal diameter within the 1/4" to 3/4" range and the order quantity when enquiring. Batch sizing may affect lead time and should be discussed with the Accurate Fastners sales team.
Request Supporting Documentation
For regulated or quality-assured projects, ask about material test reports or batch documentation at the enquiry stage. The quality control process at Accurate Fastners supports documentation requests where applicable.
FAQs
Frequently asked questions
What thread profile does the BSW 1083 Hex Nut use?
The nut carries a British Standard Whitworth (BSW) internal thread, characterised by a 55-degree flank angle and rounded crests and roots. It is designed to mate with bolts and studs cut to the same BSW thread standard, not with metric or UNC/UNF threaded fasteners.
Which stainless steel grades are available for this nut?
Accurate Fastners supplies the BSW 1083 Hex Nut in SS 202, SS 304 and SS 316. Grade selection typically depends on the service environment, with SS 316 commonly preferred where chloride or chemical exposure is a consideration. Contact the sales team to confirm current grade availability.
What is the available size range for this nut?
The size range is 1/4" to 3/4" nominal diameter. If your application requires a diameter outside this range, please contact Accurate Fastners directly via the enquiry form, email or WhatsApp to discuss whether alternative sizes can be sourced or confirmed.
Can these nuts be used with metric bolts?
No. BSW and metric thread forms use different flank angles, pitches and diameter conventions and are not interchangeable. Using a BSW hex nut on a metric bolt — or vice versa — risks cross-threading, loss of clamping load and potential assembly failure. Always confirm thread compatibility before ordering.
What other fasteners would typically be used alongside this nut?
A BSW 1083 Hex Nut is typically paired with a BSW-threaded hex bolt or stud of the same nominal diameter and grade. A flat washer under the bearing face is commonly used to distribute load, particularly on softer or coated surfaces. All mating parts should share the same thread standard.
How can I request a quotation for BSW 1083 Hex Nuts?
You may submit an enquiry through the website enquiry form, send details by email to export@accuratefastners.com, or contact the team via WhatsApp. Please include the nominal diameter, required grade, quantity and any documentation requirements to receive an accurate and timely quotation.
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