M6 Hex Head Cap Screws, Fully Threaded, Grade C are manufactured to ISO 4018 with a coarse thread pitch of 1 mm. This page lists the controlling dimensions for the M6 size — head geometry, width across flats, matching spanner size — together with the clearance hole, tapping drill and tightening torque used at assembly.
M6 Dimensional Row (ISO 4018)
| Size | Pitch P (mm) | a_max (mm) | a_min (mm) | c_max (mm) | d_a_max (mm) | d_w_min (mm) | Width across corners e (mm) | Head height k (mm) | k_max (mm) | k_min (mm) | k_w_min (mm) | r_min (mm) | Width across flats s (mm) | s_min (mm) | Length range l (mm) | Reference standard |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| M6 | 1 | 3 | 1 | 0.5 | 7.2 | 8.74 | 10.89 | 4 | 4.375 | 3.625 | 2.54 | 0.25 | 10 | 9.64 | 12~60 | ISO 4018 |
Spanner & Drive for M6 Hex Head Cap Screws, Fully Threaded, Grade C
M6 Hex Head Cap Screws, Fully Threaded, Grade C have a width across flats of 10 mm — fit a 10 mm open-ended spanner or socket. Prefer a 6-point socket over a 12-point: it loads the corners of the 10 mm hex far less, which matters on plated heads and on anything that will be re-used. Set preload with a torque wrench rather than by arm.
Hole Sizes for M6
| Coarse-thread pitch (ISO 724) | 1 mm |
|---|---|
| Through-hole / clearance (ISO 273 medium) | 6.6 mm |
| Tapping drill, coarse thread | 5 mm |
Tightening Torque for M6
| Class 8.8 (dry, ~µ 0.125) | ≈ 10 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ 15 Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 17 Nm |
Indicative dry-joint values. Lubrication can lower the required torque by 15–25%. Always confirm against the joint design, especially when going up a strength class.
Proof Load & Strength for M6
| Tensile stress area As (ISO 724) | 20.1 mm² |
|---|---|
| Proof load, class 8.8 | 12 kN |
| Proof load, class 10.9 | 17 kN |
| Proof load, class 12.9 | 20 kN |
| Min. ultimate tensile load, class 8.8 | 16 kN |
Proof load = tensile stress area × the proof stress Sp of the class, per ISO 898-1 — Sp is a lower figure than the yield stress Rp0.2 and the two are not interchangeable. The stress area is computed from this size's own diameter and pitch, so a fine-pitch designation gives the fine-pitch figure. Design the joint so the working preload stays below the proof load of the class selected.
M6 Hex Head Cap Screws, Fully Threaded, Grade C Weight
A steel M6 hex head cap screws, fully threaded, grade c at the listed 1,260 mm length weighs approximately 282 g each — about 282 kg per 1,000 pieces. Stainless A2/A4 weighs roughly the same (density 7.9–8.0 g/cm³).
Actual weight varies slightly with head form, thread and finish; use this figure for freight estimation only.
Mating Parts for M6
For M6, pair with a M6 hex nut (ISO 4032 / DIN 934) and, where used, a M6 flat washer (ISO 7089 / DIN 125A) under the head and under the nut.
When to Step Up or Down from M6
When the joint preload approaches the proof load of M6 class 8.8, step up to M8 class 8.8 (or move to M6 class 10.9). When the joint is over-specified, M5 often saves weight and cost without losing the safety margin.
Custom manufacturing · Made to drawing
Need hex head cap screws, fully threaded, grade c in a size this table does not list?
This page covers M6 hex head cap screws, fully threaded, grade c. Material and finish are usually what drives a special — a grade the standard part is not stocked in, or a coating chosen against a salt-spray figure instead of a default. Made by cold heading or hot forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
