ISO 1173 is the standard cited for magnetic bit holders and extensions. This page sets out what the standard controls for this part, reproduces the dimensional table supplied against it, and notes the related designations referenced on drawings.
ISO 1173 — Scope
The table below lists the dimensions catalogued for magnetic bit holders and extensions under ISO 1173. The scope of ISO 1173 itself is not summarised here — where a figure matters, confirm it against the published document.
Tolerance & Product Grades
Product grade is a concept from dimensional fastener standards and does not apply to ISO 1173. Tolerances for this part are the limits shown against each dimension in the table.
Dimensions Specified by ISO 1173
| Form | Drive | Typical length | Retention |
|---|---|---|---|
| magnetic bit holder | 1/4 in hex shank, C6.3 socket | 60 mm | magnet |
| magnetic bit holder | 1/4 in hex shank, C6.3 socket | 150 mm | magnet |
| quick-release bit holder | 1/4 in hex shank, C6.3 socket | 75 mm | ball detent, sprung sleeve |
| bit extension bar | 1/4 in hex shank, C6.3 socket | 300 mm | magnet |
| square-drive bit adaptor | 3/8 in square to C6.3 | 50 mm | ball detent |
Companion Standards
A complete specification for magnetic bit holders and extensions normally cites several documents: one for the geometry, one for the material or mechanical properties, and one for the finish. ISO 1173 is one of them, not all of them.
When to Specify ISO 1173
Choose ISO 1173 for international engineering work and OEM supply where ISO standards are the contractual reference. It is the default modern specification for magnetic bit holders and extensions.
Custom manufacturing · Made to drawing
Need a fastener tool to this standard in a non-standard size?
Parts built to ISO 1173 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.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
