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Screws · GB/T 70.1 / DIN 912 / ISO 4762 and GB/T 70.3 / DIN 7991 / ISO 10642 · Application guide

What Are Drilled-Head Capstan Sealing Screws Used For?

Typical applications, the industries that specify drilled-head capstan sealing screws, and how to choose the right size, material and finish for the joint.

Drilled-Head Capstan Sealing Screws are used for threaded assemblies where the head drive and seating style matter. They are manufactured to GB/T 70.1 / DIN 912 / ISO 4762 and GB/T 70.3 / DIN 7991 / ISO 10642, and the choice of size, property class and finish is driven by the load in the joint and the environment it sits in.

Primary duty
Threaded assemblies where the head drive and seating style matter
Governing standard
GB/T 70.1 / DIN 912 / ISO 4762 and GB/T 70.3 / DIN 7991 / ISO 10642
Category
Screws

Application notes are general engineering guidance. Verify the property class and any approval requirement against your own design calculation.

What Are Drilled-Head Capstan Sealing Screws Used For? application image

The primary duty of Drilled-Head Capstan Sealing Screws is threaded assemblies where the head drive and seating style matter. Below: the sectors that specify them in volume, the checklist used to select the right size and material for the application, installation notes, and the known limits of the type.

Typical Applications for Drilled-Head Capstan Sealing Screws

The most common settings where these are specified:

  • Machine guarding & panels: removable access covers that are opened for service.
  • General machine building: fastening covers, brackets, motors and sub-assemblies on production equipment.
  • Maintenance & repair (MRO): a stocked size for servicing existing plant where the original fastener spec must be matched.
  • Fabrication & metalwork: bench and on-site assembly of steel frames, enclosures and weldments.
  • Electronics & enclosures: mounting PCBs, panels and lids where the drive style and head height matter.

How to Specify Drilled-Head Capstan Sealing Screws for Your Application

  • Size: Match the size to the mating part — see the dimension table below for each option.
  • Drive & head: Pick the drive (socket, cross, slot) and head style for the tool access and seating surface; a recessed drive resists cam-out under power tools.
  • Environment: For damp, coastal or chemical exposure prefer A4/316 stainless or a suitable coating; indoors, plated steel or A2 is usually sufficient.
  • Standard: This product is supplied to GB/T 70.1 / DIN 912 / ISO 4762 and GB/T 70.3 / DIN 7991 / ISO 10642. Quoting the standard on your order guarantees interchangeable dimensions between suppliers.

Installation & Assembly Practice

  • Match the driver exactly to the recess (PH ≠ PZ; hex key sizes per ISO 2936) and keep the tool axial — side load is the main cause of stripped drives.
  • In tapped holes, engage a thread length of at least 1× the nominal diameter in steel, 2× in aluminum.
  • Set power tools to a torque that seats the head without embedding it into the mating surface.

Common Selection Mistakes with Drilled-Head Capstan Sealing Screws

  • Under-sizing the drive for the installation torque — a small recess at high torque strips before the screw is seated.
  • Using a countersunk head in thin sheet where the countersink removes most of the load-bearing material.
  • Specifying stainless in high-strength duty: A2-70 is roughly class 7 steel, not a 10.9 substitute.

Where Drilled-Head Capstan Sealing Screws Are Not the Right Choice

Not for high-preload structural joints (use a property-class bolt and nut), and not in thin sheet where a self-drilling or self-tapping type suits better.

Technical Drawing

Customize the parameters below — every spec field is editable, and the drawing redraws to match the values you choose. Changing the size will snap the other fields to that size's standard values; you can then override any individual value.

Sends the selected values to the quote form below.

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The form below follows the current technical drawing configuration. Change the drawing values above and the request details update automatically.

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Specification
Business Information

Dimensions & Specifications (GB/T 70.1 / DIN 912 / ISO 4762 and GB/T 70.3 / DIN 7991 / ISO 10642)

Head formGoverning standardsSealing featureProperty classFinish
hexagon socket head capGB/T 70.1-2008 / DIN 912 / ISO 4762cross-drilled head for sealing wire8.8black oxide
countersunk hexagon socketGB/T 70.3-2008 / DIN 7991 / ISO 10642cross-drilled head for sealing wire8.8black oxide
Inside the plant

Manufactured in our own plant

This part is cold-formed, threaded, heat-treated and finished in-house. The stages below are where its class and finish are actually decided.

  1. Wire rod feeding into a cold heading machine
    01

    Cold heading

    Wire rod is drawn to size and cold-formed into blanks. Forming rather than cutting keeps the grain flow continuous around the head, which is where a bolt is most likely to fail.

    Head dimensions and under-head radius checked at set-up and per shift.

  2. Thread rolling machine producing bolt threads
    02

    Thread rolling

    Threads are rolled between hardened dies rather than cut. Rolled threads are stronger in fatigue than cut threads and hold pitch and flank angle far more consistently across a batch.

    Go / no-go ring gauges to ISO 965 tolerance class 6g.

  3. Baskets of bolts staged for heat treatment
    03

    Heat treatment

    Quench-and-temper brings carbon and alloy steel to the property class ordered — 8.8, 10.9 or 12.9 — with the furnace charge tracked so a finished lot can be traced back to it.

    Core hardness and tensile tested per lot to ISO 898-1.

  4. Zinc plated bolts in a treatment basket
    04

    Surface treatment

    Zinc, zinc-nickel, hot-dip galvanizing, black oxide, phosphate and Dacromet, selected against the service environment rather than against the price list.

    Coating thickness and neutral salt spray hours to ISO 9227.

Frequently Asked Questions

Are Drilled-Head Capstan Sealing Screws made to a recognized standard?

Yes — they are manufactured to GB/T 70.1 / DIN 912 / ISO 4762 and GB/T 70.3 / DIN 7991 / ISO 10642, so dimensions are interchangeable between suppliers when you quote the standard on your order.

What are Drilled-Head Capstan Sealing Screws used for?

Threaded assemblies where the head drive and seating style matter. They are supplied to GB/T 70.1 / DIN 912 / ISO 4762 and GB/T 70.3 / DIN 7991 / ISO 10642.

Which industries use Drilled-Head Capstan Sealing Screws?

They are commonly specified in maintenance & repair (mro), fabrication & metalwork and electronics & enclosures, among other sectors.

How do I choose the right size of Drilled-Head Capstan Sealing Screws?

Match the size to the mating part using the dimension table on this page.

Can I get a quote for Drilled-Head Capstan Sealing Screws in the size and material I need?

Yes. Use the technical drawing and quote form on this page to set the size and options, then send the exact configuration to our team for pricing and lead time.