M36 Heavy Hex Socket Head Cap Screw are manufactured to GB/T 1228 / ASTM A325 with a coarse thread pitch of 4 mm. This page lists the controlling dimensions for the M36 size — head geometry, width across flats, matching spanner size — together with the clearance hole, tapping drill and tightening torque used at assembly.
M36 Dimensional Row (GB/T 1228 / ASTM A325)
| Size | Pitch (mm) | Length L (mm) | Head diameter dk (mm) | Head height k (mm) | Hex socket s (mm) | Reference standard |
|---|---|---|---|---|---|---|
| M36 | 4.0 | 200 | 54.0 | 36 | 27.0 | ISO 4762 / GB/T 70.1 |
Spanner & Drive for M36 Heavy Hex Socket Head Cap Screw — GB/T 1228 / ASTM A325 (Series 046)
The hex socket for M36 Heavy Hex Socket Head Cap Screw — GB/T 1228 / ASTM A325 (Series 046) is shown in the spec table — use the matching Allen / hex key (an ISO 2936 hex key set covers the full range). A T-handle Allen key gives the best feel for setting preload by feel; for production work use a torque-controlled driver.
Hole Sizes for M36
| Coarse-thread pitch (ISO 724) | 4 mm |
|---|---|
| Through-hole / clearance (ISO 273 medium) | 39 mm |
| Tapping drill, coarse thread | 32 mm |
Tightening Torque for M36
| Class 8.8 (dry, ~µ 0.125) | ≈ 2450 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ 3450 Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 4150 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 M36
| Tensile stress area As (ISO 898-1) | 817 mm² |
|---|---|
| Proof load, class 8.8 | 490 kN |
| Proof load, class 10.9 | 678 kN |
| Proof load, class 12.9 | 792 kN |
| Min. ultimate tensile, class 8.8 | 654 kN |
Proof load = stress area × proof stress per ISO 898-1. Design joints so the working preload stays below the proof load of the selected class.
M36 Heavy Hex Socket Head Cap Screw — GB/T 1228 / ASTM A325 (Series 046) Weight
A steel M36 heavy hex socket head cap screw at the listed 200 mm length weighs approximately 3,596 g each — about 3,596 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.
Common Applications for M36 Heavy Hex Socket Head Cap Screw — GB/T 1228 / ASTM A325 (Series 046)
M36 Heavy Hex Socket Head Cap Screw — GB/T 1228 / ASTM A325 (Series 046) are commonly specified for heavy assembly and large machine mounts.
Installation Tips for M36 Heavy Hex Socket Head Cap Screw — GB/T 1228 / ASTM A325 (Series 046)
- Use a quality Allen key fully seated in the socket — partial engagement is the most common cause of stripped sockets at this size.
- For countersunk and button-head variants, chamfer the through-hole to seat the head flush without preloading the head/shank fillet.
- At M36 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 M36
For M36, pair with a M36 hex nut (ISO 4032 / DIN 934) and, where used, a M36 flat washer (ISO 7089 / DIN 125A) under the head and under the nut.