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M10×1 — Full Fastener Spec
ISO 68-1 / ISO 261 · Fine series · Tap drill, clearance hole, torque, strength and tool sizes — every number on one page.
Tap drill (75% thread)
9 mm
Nearest inch drill: T (0.3580") · Clearance hole (normal fit): 11 mm ·
8.8 torque: 56.1 N·m dry
Thread dimensions
Major diameter
10 mm
Pitch
1 mm
TPI (equivalent)
25.4
Pitch diameter
9.351 mm
Minor diameter
8.918 mm
Tensile stress area
64.49 mm²
Tap drill sizes for M10×1
Percent of thread is a trade-off: 75% is the shop default because the last 25% of engagement adds only a few percent of strength while roughly doubling tapping torque. Drop to 50–65% in tough or gummy material, or for blind holes where a snapped tap means scrapping the part.
| Thread engagement | Exact | Metric drill | Nearest inch drill |
|---|---|---|---|
| 50% | 9.35 mm | 9.4 mm | 0.3680" (U drill) |
| 65% | 9.156 mm | 9.2 mm | 0.3594" (23/64 drill) |
| 75% | 9.026 mm | 9 mm | 0.3580" (T drill) |
| 85% | 8.896 mm | 8.9 mm | 0.3480" (S drill) |
Roll (form) taps need a larger hole than cut taps — add roughly
0.4× the pitch to the 75% cut-tap drill and confirm against your tap maker's chart.
Clearance hole for M10×1
| Fit | Hole | Use |
|---|---|---|
| Close | 10.5 mm | Located joints, dowel-like alignment |
| Normal | 11 mm | General assembly — use this unless you have a reason not to |
| Loose | 12 mm | Weldments, sheet stacks, tolerance build-up |
M10×1 torque specs
Calculated with the short-form equation T = K · D · F, using K = 0.2 (plain, dry, as-received steel) and a target clamp load of 75% of proof load — the standard preload target for a reusable joint.
| Grade | Dry | Lubricated | Dry (lb-ft) | Clamp load |
|---|---|---|---|---|
| 4.6 Low-carbon steel, general purpose | 21.8 N·m | 16.3 N·m | 16.1 lb-ft | 10.9 kN |
| 8.8 Medium-carbon, quenched & tempered — the default structural grade | 56.1 N·m | 42.1 N·m | 41.4 lb-ft | 28.1 kN |
| 10.9 Alloy steel, Q&T — high strength | 80.3 N·m | 60.2 N·m | 59.2 lb-ft | 40.1 kN |
| 12.9 Alloy steel, Q&T — highest common grade (socket head cap screws) | 93.8 N·m | 70.4 N·m | 69.2 lb-ft | 46.9 kN |
| A2-70 304 stainless, cold worked | 43.5 N·m | 32.7 N·m | 32.1 lb-ft | 21.8 kN |
The nut factor K dominates this result. Zinc-plated, waxed, anti-seize
and lubricated threads all shift K between roughly 0.10 and 0.25, which is a 2.5×
spread in torque for identical preload. If preload actually matters, torque-to-yield,
angle control or a load-indicating washer beats a torque wrench every time.
Tool sizes
Hex head wrench
16 mm or 17 mm (DIN)
Hex key (socket head)
8 mm