BSW Countersunk Socket Screw 3/16 10B21 Carbon Steel — stocked and shipped worldwide by SFX Fasteners. Available for single-piece retail orders — no minimum order — dispatched from our own warehouse within 24–48 hours.
Specifications
| Material | 10B21 Carbon Steel |
| Grade | Grade 10.9 |
| Diameter | 3/16 |
| Surface Finish | Black Oxide |
| Brand | SFX Fasteners |
Ordering & shipping
| Minimum order | No minimum — single pieces welcome |
| Pricing | Order totals are confirmed at checkout, before payment |
| Custom & dropship | Small batches to drawing · blind dropshipping on request |
| Dispatch | 24–48 hours for stock items |
| Shipping | Worldwide, calculated at checkout by weight and destination |
Need a specific size, grade or standard? Send us a quote request — we quote to drawing and to DIN / ANSI / GB / JIS standards.
About this screw
This is a screw in 10B21 Carbon Steel, at strength class Grade 10.9, supplied black oxide, with an 3/16 thread. Every dimension is stated against the standard named above; where a tolerance class matters to your design, ask us and we will confirm it in writing before you order.
A screw threads directly into the parent material or into a nut, so the thread form, the point and the drive decide what it can be used for. Commonly used on machinery, tooling, appliances, electrical enclosures, furniture and automotive assemblies where the head has to sit low or be driven from one side only.
10B21 is a boron-treated low-carbon steel used for grade 8.8 fasteners where formability matters. It hardens reliably with a small boron addition.
Black oxide is a conversion coating about 1–2 µm thick, usually oiled. It adds mild corrosion resistance and keeps dimensions exact, which matters on 10.9 and 12.9 parts — there is no hydrogen embrittlement risk.
Is this not quite the size or grade you need? Ask us — we produce small batches to drawing and to DIN, ISO, GB and JIS standards, and we consolidate pallet and container loads for trade orders.


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