---
title: "What Are Drilled-Head Capstan Sealing Screws Used For?"
description: "Drilled-Head Capstan Sealing Screws (GB/T 70.1 / DIN 912 / ISO 4762 and GB/T 70.3 / DIN 7991 / ISO 10642) are used for threaded assemblies where the head dri…"
url: https://engineeringhardware.com/applications/drilled-head-capstan-sealing-screws/
source: Engineering Hardware & Fasteners
---

# What Are Drilled-Head Capstan Sealing Screws Used For?

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

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](https://engineeringhardware.com/wp-content/uploads/2026/09/Drilled-Head-Capstan-Sealing-Meter-Screws.webp)

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.

Product catalog

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## 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.

Custom manufacturing · Made to drawing

## Need a drilled-head capstan sealing screws outside the standard range?

Where the standard stops, the drawing takes over: fine pitches, left-hand threads, partial threading, and property classes above the catalogued grade where material and heat treatment allow. Made by cold heading or warm forging.

Minimum order from 2,000 pieces; samples within 7 days of drawing approval.

[Custom screw manufacturing](https://engineeringhardware.com/custom/screws/)[Send a drawing](https://engineeringhardware.com/custom/screws/#rfq)

## Technical Drawing

Dimensioned line drawing of hexagon socket head cap Drilled-Head Capstan Sealing Screws to GB/T 70.1 / DIN 912 / ISO 4762 and GB/T 70.3 / DIN 7991 / ISO 10642. Side view and top view, drawn to the dimensions in the table below and redrawn for any size selected.

- **Governing standards:** GB/T 70.1-2008 / DIN 912 / ISO 4762
- **Sealing feature:** cross-drilled head for sealing wire
- **Property class:** 8.8
- **Finish:** black oxide

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

| Head form | Governing standards | Sealing feature | Property class | Finish |
| --- | --- | --- | --- | --- |
| hexagon socket head cap | GB/T 70.1-2008 / DIN 912 / ISO 4762 | cross-drilled head for sealing wire | 8.8 | black oxide |
| countersunk hexagon socket | GB/T 70.3-2008 / DIN 7991 / ISO 10642 | cross-drilled head for sealing wire | 8.8 | black 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](https://engineeringhardware.com/wp-content/uploads/2026/08/09-wire-rod-feed-cold-heading-machine.webp) 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](https://engineeringhardware.com/wp-content/uploads/2026/08/03-thread-rolling-machine-bolt-production.webp) 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](https://engineeringhardware.com/wp-content/uploads/2026/08/05-heat-treatment-baskets-black-bolts.webp) 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](https://engineeringhardware.com/wp-content/uploads/2026/08/23-zinc-plated-bolts-treatment-basket.webp) 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.

## Related Pages

Product page: [Drilled-Head Capstan Sealing Screws — specifications & sizes](https://engineeringhardware.com/fastener/drilled-head-capstan-sealing-screws/)

### Drilled-Head Capstan Sealing Screws Specification Guides

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