BS 916 Hexagon Head Screws with B.S. Threads (1953, Table 1)
BS 916-1953 table 1 hexagon head screws with British Standard threads: threads per inch, across flats and corners, fillet radius and head height across the B.S. size ladder — the black/hex general engineering screw of the Whitworth era.
Last updated: 2026-11
Specifications
BS 916 is the general-engineering hexagon head screw standard of the British thread era, and the collected table 1 carries a 15-size ladder (the two thread-count rows run 20 down to 2.5 TPI across the range) with across flats s max/min (0.445/0.435 at the smallest to 9.450/9.325 at the largest — the ladder reaching very large diameters by modern standards), across corners e max/min (0.435 upward to 10.91 max), fillet radius R, and head height k max/min (1.27/1.17 climbing to 4.20/4.00 in its later rows). The collected page prints no size-designation header row — sizes are carried by the thread-count and s rows, read vertically. This is the coarse "black bolt of the hex screw world" identity for heritage British plant: coarser geometry and wider tolerances than BS 1083 precision screws, on the same B.S. thread systems.
| Standard / scope | BS 916-1953 table 1 — hexagon head screws with B.S. threads (BSW/BSF series), 15 sizes as tabulated; no printed size headers (sizes carried by the TPI and s rows, read vertically) |
|---|---|
| Threads per inch | 20, 18, 16, 14, 12, 12, 11, 10, 9, 8, 7, 7, 6, 6, 5... down to 2.5 — B.S. ladder as printed, one '/' cell carried verbatim |
| Width across flats s | Max/min: 0.445/0.435 (smallest) to 9.450/9.325 in — the ladder extends into very large diameters |
| Width across corners e | Max/min: 0.435... to 10.91 max as printed |
| Head height k / fillet R | k max/min 1.27/1.17 to 4.20/4.00 in its later rows; R per size |
| Not tabulated | Strength, lengths, finishes — per RFQ |
Materials
- BS 916 screws are the general black/self-colour hex supply of the Whitworth era — coarser than BS 1083 precision screws and used where appearance and tight tolerances were not the point. As maintenance stock they survive wherever old British general engineering plant still runs; the large-diameter end of the ladder (the inch-wide and bigger sizes) is the range most often needed for restoration and least often held in stock, so quote it with lead-time expectation. Confirm BSW vs BSF by thread gauge as with all B.S. hardware
Ordering & documentation
Documents
Shipments are backed by Mill Test Certificate (MTC), Dimensional Report, Salt Spray Test Report on request, with full batch traceability from raw material to finished product. Quality management follows the owner-confirmed compliance list: ISO 9001:2015, RoHS, REACH. Exact document sets are confirmed on the order.
Quotation
- The fastener family (BS 916 Hexagon Head Screws with B.S. Threads (1953, Table 1)) plus the standard designation from your drawing — DIN / ISO / JIS / ASTM / ANSI, or a drawing for custom parts.
- Size (diameter and length), thread type (metric or inch), property class or grade, and coating or finish.
- Quantity per size and your target delivery date.
- Destination country, and any required documents (for example a mill test certificate) so the quote includes them.
Sample & supply
Minimum order quantity is 10,000 pieces. Stock items run 3–7 days. Quantities or variants outside the standard range are confirmed at quotation.
Storage & shipping
Parts are packed for export and shipped factory-direct to buyers in Europe, Asia, the Americas and the Middle East. Store fasteners dry and protected until installation, and keep coated parts in their packaging until use; specific packing and preservation requirements can be stated on the order and confirmed at quotation.
Frequently asked questions
How does BS 916 differ from BS 1083 for the same B.S. thread size?
Precision versus general engineering. BS 1083 screws are washer-faced with tighter geometric tolerances; BS 916 screws are the broader-tolerance general version — same thread system, coarser head control, no washer face requirement. In a restoration the visible difference is the bearing face and the finish of the head; functionally the thread is the same family, so the two interchange only where the joint tolerates the coarser seat. This table's larger size range is its practical advantage: BS 916 covers the very large diameters the precision ladder does not, which is why plant restoration keeps both standards on the shelf.
The table has no size headers — how are sizes identified?
The collected page prints the thread-count row (TPI) and the across-flats row as the identifying ladders — read each column vertically: TPI, then s max/min, then e, R and k. A "3/8 BSW" is the column whose TPI reads 16 and whose s matches the 3/8-inch across-flats ladder. The batch anomalyFlags also note the single "/" cell where the source leaves a thread count untabulated. As always with B.S. hardware, verify the physical part against a thread gauge before assembly — the designation, not the column position, is what the order carries.
Related knowledge
- Thread-Forming vs Thread-Cutting vs Thread-Rolling Self-Tapping Screws: What the Evidence Settles on Base Material
- Screw Family Selection by Base Material: Wood, Machine and Self-Tapping Threads, Engagement and Coating
- Hex Bolts vs Socket Head Cap Screws: What the Evidence Settles on Strength, Clearance and Cost
Request a Quote
Get factory-direct pricing from the manufacturer.
What to include in your inquiry
- ✓ Standard and property class (e.g. DIN 912, ISO 4762, class 8.8) — or a drawing for custom parts.
- ✓ Sizes, lengths and thread type (metric or inch).
- ✓ Quantity per size and your target delivery date.
- ✓ Destination country, plus any coating or finish requirement.
- ✓ Any documents you need with the shipment (e.g. mill test certificate) so the quote includes them.
- ✓ Your inquiry goes straight to the factory team by email and gets a reply within 24 hours.
- ✓ Factory-direct pricing
- ✓ Standard and custom specifications
- ✓ Factory-direct export to buyers in Europe, Asia, the Americas and the Middle East
- ✓ Full fastener family support