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M12×1.75 — Full Fastener Spec
ISO 68-1 / ISO 261 · Coarse series · Tap drill, clearance hole, torque, strength and tool sizes — every number on one page.
Tap drill (75% thread)
10.2 mm
Nearest inch drill: Y (0.4040") · Clearance hole (normal fit): 13.5 mm ·
8.8 torque: 88 N·m dry
Thread dimensions
Major diameter
12 mm
Pitch
1.75 mm
TPI (equivalent)
14.51
Pitch diameter
10.863 mm
Minor diameter
10.106 mm
Tensile stress area
84.27 mm²
Tap drill sizes for M12×1.75
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% | 10.863 mm | 10.9 mm | 0.4219" (27/64 drill) |
| 65% | 10.522 mm | 10.5 mm | 0.4130" (Z drill) |
| 75% | 10.295 mm | 10.2 mm | 0.4040" (Y drill) |
| 85% | 10.068 mm | 10.1 mm | 0.3970" (X 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 M12×1.75
| Fit | Hole | Use |
|---|---|---|
| Close | 13 mm | Located joints, dowel-like alignment |
| Normal | 13.5 mm | General assembly — use this unless you have a reason not to |
| Loose | 14.5 mm | Weldments, sheet stacks, tolerance build-up |
M12×1.75 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 | 34.1 N·m | 25.6 N·m | 25.2 lb-ft | 14.2 kN |
| 8.8 Medium-carbon, quenched & tempered — the default structural grade | 88 N·m | 66 N·m | 64.9 lb-ft | 36.7 kN |
| 10.9 Alloy steel, Q&T — high strength | 126 N·m | 94.4 N·m | 92.9 lb-ft | 52.5 kN |
| 12.9 Alloy steel, Q&T — highest common grade (socket head cap screws) | 147 N·m | 110 N·m | 109 lb-ft | 61.3 kN |
| A2-70 304 stainless, cold worked | 68.3 N·m | 51.2 N·m | 50.3 lb-ft | 28.4 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
18 mm or 19 mm (DIN)
Hex key (socket head)
10 mm