Home › M6×0.75
M6×0.75 — 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)
5.25 mm
Nearest inch drill: #5 (0.2055") · Clearance hole (normal fit): 6.6 mm ·
8.8 torque: 11.5 N·m dry
Thread dimensions
Major diameter
6 mm
Pitch
0.75 mm
TPI (equivalent)
33.87
Pitch diameter
5.513 mm
Minor diameter
5.188 mm
Tensile stress area
22.03 mm²
Tap drill sizes for M6×0.75
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% | 5.513 mm | 5.5 mm | 0.2188" (7/32 drill) |
| 65% | 5.367 mm | 5.4 mm | 0.2130" (#3 drill) |
| 75% | 5.269 mm | 5.25 mm | 0.2055" (#5 drill) |
| 85% | 5.172 mm | 5.2 mm | 0.2040" (#6 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 M6×0.75
| Fit | Hole | Use |
|---|---|---|
| Close | 6.4 mm | Located joints, dowel-like alignment |
| Normal | 6.6 mm | General assembly — use this unless you have a reason not to |
| Loose | 7 mm | Weldments, sheet stacks, tolerance build-up |
M6×0.75 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 | 4.46 N·m | 3.35 N·m | 3.29 lb-ft | 3.7 kN |
| 8.8 Medium-carbon, quenched & tempered — the default structural grade | 11.5 N·m | 8.63 N·m | 8.48 lb-ft | 9.6 kN |
| 10.9 Alloy steel, Q&T — high strength | 16.5 N·m | 12.3 N·m | 12.1 lb-ft | 13.7 kN |
| 12.9 Alloy steel, Q&T — highest common grade (socket head cap screws) | 19.2 N·m | 14.4 N·m | 14.2 lb-ft | 16 kN |
| A2-70 304 stainless, cold worked | 8.92 N·m | 6.69 N·m | 6.58 lb-ft | 7.4 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
10 mm
Hex key (socket head)
5 mm