Skip to content
info@engineeringhardware.com
WhatsApp
Request a Quote
Engineering Reference · Clearance Hole Sizes

Clearance Hole Sizes

33 catalogued sizes, dimensioned to ISO 273. Pick any row and the technical drawing redraws to it.

Clearance Hole Sizes to ISO 273 are catalogued in sizes M1 to M64. 33 sizes are held in the table below, and the technical drawing redraws to whichever row you select.

Standard
ISO 273
Size range
M1-M64
Catalogued sizes
33

Dimensions are nominal values from the governing standard. Confirm the tolerance class for your application before ordering.

Clearance Hole Sizes technical product image

Clearance Hole Sizes conform to ISO 273. As engineering reference, they are specified by the dimensions in the table below; this page also covers materials, finishes and typical uses.

About This Reference

This is an engineering reference table for clearance hole sizes based on ISO 273. Use it alongside our fastener catalog when selecting and specifying parts.

Reference Data (ISO 273)

Thread size Fine H12 (mm) Medium H13 (mm) Coarse H14 (mm) Reference standard Application
M1 1.1 1.2 1.3 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M1.2 1.3 1.4 1.5 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M1.4 1.5 1.6 1.8 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M1.6 1.7 1.8 2.0 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M2 2.2 2.4 2.6 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M2.5 2.7 2.9 3.1 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M3 3.2 3.4 3.6 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M3.5 3.7 3.9 4.2 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M4 4.3 4.5 4.8 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M5 5.3 5.5 5.8 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M6 6.4 6.6 7.0 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M7 7.4 7.6 8.0 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M8 8.4 9.0 10.0 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M10 10.5 11.0 12.0 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M12 13.0 13.5 14.5 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M14 15.0 15.5 16.5 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M16 17.0 17.5 18.5 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M18 19.0 20.0 21.0 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M20 21.0 22.0 24.0 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M22 23.0 24.0 26.0 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M24 25.0 26.0 28.0 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M27 28.0 30.0 32.0 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M30 31.0 33.0 35.0 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M33 34.0 36.0 38.0 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M36 37.0 39.0 42.0 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M39 40.0 42.0 45.0 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M42 43.0 45.0 48.0 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M45 46.0 48.0 52.0 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M48 50.0 52.0 56.0 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M52 54.0 56.0 62.0 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M56 58.0 62.0 66.0 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M60 62.0 66.0 70.0 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
M64 66.0 70.0 74.0 ISO 273 / DIN 406 Clearance (through) hole, non-threaded
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.

Video: Clearance Hole Sizes

Clearance hole and tap size calculation

Third-party video, selected automatically for this topic. It is not produced by Engineering Hardware and is not a specification source — use the tables on this page for dimensional data.

Frequently Asked Questions

What does the Clearance Hole Sizes reference table cover?

Clearance Hole Sizes is an engineering reference table aligned with ISO 273. Use the values alongside our fastener catalog when selecting and specifying parts.

How do I request a quotation?

Use the parametric drawing on this page to set the exact configuration (size, material, finish) and click "Request this configuration" — a specialist from Engineering Hardware will respond within one business day.