Drilled-Head Capstan Sealing Screws manufactured to ISO 4762 are dimensioned by the size table reproduced on this page. The standard fixes geometry and tolerances only; material and property class are assigned by separate documents, and surface finish by separate finish standards.
ISO 4762 — Scope
ISO 4762 is "Hexagon socket head cap screws". The metric socket cap screw; the closely related DIN 912 covers the same form.
Material, property class, surface finish and packaging are governed by separate documents — ISO 898-1 and ISO 898-2 for mechanical property classes, ISO 4042 for electroplated finishes.
Tolerance & Product Grades
ISO 4762 does not divide drilled-head capstan sealing screws into product grades. Tolerances are given as limits on the individual dimensions in the table.
Where a general-tolerance class is cited on the drawing instead, it applies to the dimensions not otherwise toleranced.
Dimensions Specified by ISO 4762
| 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 |
Equivalent Standards
ISO 4762 socket head cap screws correspond to DIN 912.
Companion Standards
ISO 4762 controls only the geometry of drilled-head capstan sealing screws. The mechanical strength is set by ISO 898-1 (bolts, screws and studs) or ISO 898-2 (nuts); the surface finish is governed by separate finish standards such as ISO 4042 for electroplating. For corrosion testing, the relevant document is ISO 9227 (neutral salt spray).
Custom manufacturing · Made to drawing
Need a screw to this standard in a non-standard size?
Parts built to ISO 4762 are already in the catalog, so a special is usually a variation on existing tooling rather than a new design — which is what keeps the cost down. Made by cold heading or warm forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
Custom screw manufacturingSend a drawing
Applications & Industries
Drilled-Head Capstan Sealing Screws are bought for a small number of well-defined jobs. These are the ones we ship them for. Stocked from hexagon socket head cap to countersunk hexagon socket (nominal diameter).
Industries that specify Drilled-Head Capstan Sealing Screws
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Regulated installations
Evidence of an unbroken seal on inspection.
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Utility metering
A cross-drilled head takes a sealing wire that shows tampering.
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Instrument enclosures
Closure control on calibrated equipment.
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Test and measurement
Sealed access for certified instruments.
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Food, pharma & cleanroom
Stainless assemblies that are washed down, where the finish matters as much as the strength.
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Machine building & OEM
The default fastener on production equipment: covers, brackets, motor mounts and sub-assemblies tightened to a specified torque.
Typical applications
- recording the seal number against the installation
- threading a sealing wire through the drilled head and crimping it
- choosing the cap or countersunk form for the enclosure detail
- specifying class 8.8 black oxide as listed
- joints where the property class is stated on the drawing
- clamping two machined faces to a calculated preload
Service conditions to specify against
- Marine and coastal
- Available in A4 (316) stainless for chloride exposure — coastal structures, pool halls, water treatment and deck hardware, where A2 will eventually pit.
- High load
- Supplied in ISO 898-1 property classes, so the joint can be designed to a stated proof load and tightened to a calculated torque rather than by feel.
- Sealed joints
- Used where the fixing has to keep water or air out as well as hold — the elastomer, not the fastener, decides service life.
- Torque and preload
- The joint is designed around bolt tension, so lubrication, coating and the friction coefficient all change the torque figure — state them together.
Where to use something else
- Do not fit a sealing screw without actually closing the wire; an undrawn seal proves nothing.
- Do not use a machine thread into unthreaded sheet or timber; use a tapping screw, rivet nut or insert made for that parent material.
Full application guide: where Drilled-Head Capstan Sealing Screws are used, how to specify them, and the cases they are wrong for
