M27 Hex Bolts, Grade C are manufactured to ISO 4016 with a coarse thread pitch of the standard value. This page lists the controlling dimensions for the M27 size — head geometry, width across flats, matching spanner size — together with the clearance hole, tapping drill and tightening torque used at assembly.
M27 Dimensional Row (ISO 4016)
| Size | Pitch (mm) | Width across flats s (mm) | Width across corners e min (mm) | Head height k (mm) | Product grade | Reference standard |
|---|---|---|---|---|---|---|
| M27 | 3.0 | 41.0 | 45.2 | 17.92 | Grade C | ISO 4016 / DIN 601 |
Spanner & Drive for M27 Hex Bolts, Grade C
M27 Hex Bolts, Grade C have a width across flats of 41.0 mm — fit a 41.0 mm open-ended spanner or socket. Use a 6-point socket for tight clearances and to reduce rounding; for repeated assembly choose a torque wrench so the joint preload is repeatable.
Common Applications for M27 Hex Bolts, Grade C
M27 Hex Bolts, Grade C are commonly specified for structural steelwork, heavy machinery foundations and large flange joints.
Installation Tips for M27 Hex Bolts, Grade C
- Use a 6-point socket where access allows — 12-point sockets are more prone to rounding the corners on smaller sizes.
- On flanged or serrated variants, do NOT add a separate flat washer — the flange already spreads the load and the washer can defeat the locking serrations.
- At M27 the stretch in the bolt becomes the controlling factor — for critical joints, use angle-controlled or stretch-controlled tightening instead of pure torque.
Mating Parts for M27
For M27, pair with a M27 hex nut (ISO 4032 / DIN 934) and, where used, a M27 flat washer (ISO 7089 / DIN 125A) under the head and under the nut.
