HANDA. NINGBO

Part group 08 / 05 · Ningbo, China

Socket head cap screws,
DIN 912 at class 12.9.

The screw that sits below the surface and still takes torque: DIN 912 with the hex socket held to the standard, class 12.9, black oxide as the default finish.

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Specification

Socket Cap Screws to drawing

Standards
DIN 912 / ISO 4762, ANSI B18.3 inch series, and special heads, lengths or materials to drawing.
Sizes
M3 to M20 standard, M24 quoted. Length 5 to 200 mm; longer sizes headed from bar so the head stays concentric.
Property class
12.9 as standard, 10.9 on request for shock-loaded joints, A2-70 and A4-80 in stainless.
Socket
Hex socket to the standard key size and depth, checked with a key gauge every batch. A shallow or worn broach is the usual failure in cheap stock, so the tool is rejected before the socket goes soft.
Finish
Black oxide as default, then zinc, nickel, zinc-nickel, Dacromet, or plain for stainless. Coating thickness reported on the inspection sheet.

Every dimension is taken from your drawing or sample. Where this page and your drawing disagree, your drawing wins.

Where these parts go

Applications

Below-surface joints on machines and fixtures, where the socket has to take torque every day without rounding out.

Bolts

Hex, socket, flange, carriage and special-head bolts, class 8.8 to 12.9.

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Screws

Machine, self-tapping, self-drilling, set and security screws to drawing.

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Turned Parts

Pins, shafts, spacers, bosses and special components from bar stock.

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Hex Bolts

DIN 931 and 933, class 8.8 / 10.9 / 12.9, hot-dip galvanised to ISO 10684.

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Questions buyers ask

01
Is class 12.9 too brittle?
It is strong and less ductile than 10.9 at 1200 MPa tensile. For shock-loaded joints 10.9 is often the better engineering choice. Tell us what the joint does and we quote the class it needs instead of substituting quietly.
02
Why do socket screws fail at the socket?
Almost always a shallow socket or a worn broach, so the key cams out and rounds the hex. We check socket depth and key engagement per batch and change the tool before quality drops.
03
Black oxide or zinc?
Black oxide with an oil film is the toolroom default. Zinc is for damp or outdoor service, and on a 12.9 screw it needs a bake against hydrogen embrittlement, which we record on the lot.
04
Can you make extra-long socket screws?
Yes. Up to 200 mm as standard, longer per drawing, headed from bar rather than cut from a longer screw so the head and shank stay concentric.
05
Do you mark the key size on the head?
The standard does not require it, but we can mark it if your fitters work from mixed stock, and the measured socket size can be reported on request.
06
How are small sizes packed?
One kilogram bags inside a carton for small sizes, five kilogram bags above that. Counted by weight against a counted sample and labelled with size, class and lot.

Next step

Send one drawing.
Get a costed sheet.

Drawing or sample, material, quantity, and the destination port. We reply within one working day with unit price, tooling, lead time and shipping.

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