BSW Countersunk Socket Screw 3/8 10B21 Carbon Steel

BSW Countersunk Socket Screw 3/8 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

Ordering & shipping

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 3/8 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.

Grade 10.9 is alloy steel at 1000 MPa tensile / 900 MPa yield, typically supplied black oxide or Dacromet. Avoid electroplated zinc on 10.9 — acid pickling risks hydrogen embrittlement.

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.

This line ships worldwide from our own warehouse. Express courier, air parcel and postal services are all offered at checkout, with a tracking number e-mailed as soon as the parcel is handed over.