Bolts · BSW 1083
BSW 1083 Hex Bolt
The BSW 1083 Hex Bolt is a cold forged, hexagon-head fastener manufactured to British Standard Whitworth thread form in stainless steel grades SS 202, SS 304 and SS 316. Accurate Fastners supplies these bolts from Ahmedabad across domestic and international markets.
- Standard
- BSW 1083
- Grades
- 304 / 316 / 202
- Size
- 1/4" – 3/4"
- Length
- 1/2" – 6"
Overview
What is the BSW 1083 Hex Bolt?
BSW 1083 designates a hexagon bolt produced to the British Standard Whitworth inch-thread system, one of the oldest and most widely recognised thread standards in engineering. The Whitworth thread form features a 55-degree flank angle and rounded crests and roots, which distinguishes it clearly from the 60-degree profiles used in metric and Unified thread families. Accurate Fastners manufactures these bolts to comply with BS dimensional requirements, supporting customers who maintain legacy equipment or source components for export markets where BSW hardware remains prevalent.
Each bolt in this range features a hexagonal head designed to be driven by a standard open-ended spanner or socket tool applied to the external flats. The cold forging manufacturing process compresses the stainless steel billet under high pressure without removing material, which may contribute to a refined grain structure compared with cut alternatives. Diameters are available from 1/4 inch to 3/4 inch and lengths from 1/2 inch to 6 inches, offering a broad range suitable for varied assembly thicknesses and clamping requirements.
Accurate Fastners' quality control team carries out checks at both the procurement and delivery stages, verifying that incoming raw material and outgoing finished bolts meet the required dimensional and surface standards. The use of stainless steel as the base material means these bolts are generally associated with resistance to rust and staining compared with plain carbon steel equivalents, making them a common choice in environments where appearance and longevity of the fastener are considerations alongside mechanical performance.
In Depth
Product description
Construction and Geometry
The bolt body is cold forged from stainless steel bar, producing a one-piece shank with an integral hexagonal head. Head geometry conforms to BSW 1083 across the flat and height dimensions for the given nominal diameter. The thread is cut or rolled to the Whitworth form — 55-degree included angle, rounded roots and crests — at the pitch specified for each inch-series diameter from 1/4 inch through 3/4 inch.
Shank length is selectable from 1/2 inch to 6 inches, allowing the engineer to choose a grip length that suits the stack of components being clamped. The underside of the hex head is flat and bears against the surface of the joined part or a washer, distributing the clamping load across the bearing face. Overall bolt dimensions follow BS requirements, facilitating interchangeability with mating BSW nuts and washers.
Functional Behaviour in an Assembly
When tightened against a BSW nut or into a Whitworth-tapped hole, the bolt stretches elastically and the resulting tension holds the joint in compression. The 55-degree Whitworth flank angle and the rounded thread form are associated with good resistance to cross-threading during assembly and with relatively consistent friction characteristics under torque. A spanner or socket applied to the hex head allows controlled tightening without specialised tooling.
In stainless steel assemblies, particular attention is typically paid to lubrication and tightening speed to reduce the risk of galling — a form of adhesive wear that may occur when austenitic stainless steel threads contact each other under pressure. Using an appropriate anti-seize compound or PTFE-based lubricant before assembly is commonly recommended practice for stainless fasteners in general engineering guidance.
How It Differs from Similar Fasteners
The BSW 1083 Hex Bolt is distinguished from its metric DIN 931/933 counterparts by thread form and pitch: Whitworth uses an inch-based pitch table and a 55-degree profile, whereas metric bolts use a 60-degree profile and ISO pitch series. The two thread families are not interchangeable. Similarly, the Unified National Coarse (UNC) thread also uses 60 degrees, so BSW and UNC bolts of nominally similar diameters are not compatible in the same tapped hole.
Within the hexagon bolt category, BSW 1083 bolts differ from socket-head cap screws in their drive method: the external hex is engaged from outside using a spanner or socket, whereas a socket head requires an internal hex key. This makes BSW hex bolts more accessible with basic hand tools and may be preferred where clearance around the bolt head is not restricted.
Material & Grade
Material and grade information
- SS 304
- SS 316
- SS 202
These bolts are available in three stainless steel grades: SS 202, SS 304 and SS 316. SS 304 is an austenitic grade containing approximately 18% chromium and 8% nickel and is commonly used in general industrial and food-contact environments. SS 316 adds molybdenum to the alloy, which is typically associated with improved resistance to chloride-containing environments compared with SS 304. Grade selection should be guided by the specific chemical exposure and service conditions of the application.
SS 202 is a lower-nickel, higher-manganese variant that is generally more economical than SS 304 while still offering better corrosion resistance than mild steel in many indoor or mildly humid environments. It is commonly selected when cost is a primary consideration and exposure to aggressive chemicals or marine atmospheres is not anticipated. Customers uncertain about which grade suits their conditions are encouraged to discuss their application details with the Accurate Fastners sales team before placing an order.
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 | Bolt – BSW 1083 Hex Bolt |
|---|---|
| Material | Stainless steel |
| Material grade | SS 304, SS 316, SS 202 |
| Applicable standard | BSW 1083 |
| Nominal diameter / size | 1/4" – 3/4" |
| Length | 1/2" – 6" |
| Thread type | BSW (British Standard Whitworth), inch |
| Head / form | Hexagon head |
| Drive / tightening | External hex (spanner / socket) |
| Manufacturing process | Cold forged |
Sizes
Available sizes
Documented size range
1/4" – 3/4"
Documented length range
1/2" – 6"
Individual sizes within the documented range, thread pitches and lengths are confirmed at quotation stage.
Applications
Industrial applications
Water Treatment Equipment
BSW hex bolts in SS 304 or SS 316 may be used to fasten housings, brackets and filter assemblies in RO water purifier systems where resistance to moisture and frequent cleaning is a practical requirement.
Submersible Pump Assemblies
Whitworth threads are found in legacy submersible pump designs. These cold forged bolts can serve as replacements or service parts in pump bodies and motor housings where BSW-threaded holes are already present.
Solar Energy Mounting Structures
Stainless steel BSW bolts are suitable for fastening panel brackets and support frames in solar installations where long service life and resistance to outdoor weathering are common considerations for the fastener choice.
Food and Beverage Machinery
SS 316 grade bolts are commonly specified for food processing and beverage machinery where contact with wash-down solutions or mild acids may occur, and where hygienic surface conditions on fasteners are a general requirement.
Pharmaceutical Machinery
In pharmaceutical equipment fabrication, stainless steel hex bolts with controlled dimensions and traceable material grades are typically preferred. The available range of lengths and diameters supports varied panel and frame assembly requirements.
Features & Selection
Features and selection considerations
Design features
Cold Forged Construction
The cold forging process shapes the bolt head and shank without cutting away material, which may contribute to improved grain flow and consistent dimensional form across the production batch.
BSW Thread Form
The 55-degree Whitworth thread with rounded roots and crests provides compatibility with BSW-tapped holes and nuts, supporting legacy equipment maintenance and British-standard compliant assemblies.
Hexagonal External Drive
The six-flat head accepts standard open-ended spanners and sockets without specialised tooling, making these bolts straightforward to install and remove in most workshop and field conditions.
Wide Size Range
Diameters from 1/4 inch to 3/4 inch and lengths from 1/2 inch to 6 inches allow selection across a broad range of clamping depths and joint configurations within a single product family.
Three Stainless Steel Grades
Availability in SS 202, SS 304 and SS 316 enables grade selection based on corrosion environment and budget, with all three options manufactured from high-quality stainless steel raw material.
Before you order
Confirm Thread Compatibility
Verify that the mating nut or tapped hole is BSW (Whitworth) thread form and not metric or UNC. Thread gauges or component drawings should be consulted before ordering, as the thread families are not interchangeable.
Choose the Correct Length
Select a bolt length that provides adequate thread engagement in the nut or tapped hole while not protruding excessively. Account for the combined thickness of all clamped components, washers and any additional elements in the joint stack.
Select an Appropriate Grade
Consider the chemical environment, moisture level and cleaning regime of the application. SS 316 is generally preferred for aggressive or chloride-rich conditions; SS 304 suits general industrial use; SS 202 is a cost-conscious option for mild environments.
Specify Quantity and Request Documentation
Provide the required quantity and ask for material test reports or dimensional inspection records where your project demands traceability. Accurate Fastners' quality control team performs checks at procurement and delivery to support this.
FAQs
Frequently asked questions
What does BSW 1083 mean on a hex bolt?
BSW refers to British Standard Whitworth, an inch-series thread standard featuring a 55-degree flank angle and rounded roots and crests. The 1083 designation identifies the specific BS specification governing the hex bolt dimensions. These bolts are not interchangeable with metric or UNC threaded fasteners.
Which stainless steel grades are available for this bolt?
Accurate Fastners offers BSW 1083 Hex Bolts in SS 202, SS 304 and SS 316. Each grade has different alloy content and is generally associated with different levels of corrosion resistance, so the appropriate grade should be selected based on the service environment and application requirements.
What diameter and length options are available?
Diameters range from 1/4 inch to 3/4 inch and lengths from 1/2 inch to 6 inches. This range covers a broad variety of joint configurations. If a specific size combination within this range is required, it is advisable to confirm availability with the sales team when requesting a quotation.
Can these bolts be used with metric nuts or DIN washers?
No. BSW hex bolts carry a Whitworth thread form and inch-series dimensions that are not compatible with metric nuts or DIN washers designed for ISO threads. Mating components must also be specified to the BSW or BS standard to ensure correct thread engagement and bearing-face fit.
What mating fasteners are typically used with a BSW hex bolt?
BSW hex bolts are typically paired with BSW hex nuts and flat washers dimensioned to the same inch-series standard. Spring washers or locking nuts in the BSW series may also be used where vibration resistance is a consideration in the assembly design.
How can I request a quotation from Accurate Fastners?
You may submit your enquiry through the website enquiry form, send details by email to export@accuratefastners.com, or contact the team via WhatsApp. Please include the required grade, diameter, length and quantity so that an accurate quotation can be prepared promptly.
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