M2.5 Hexalobular Socket Head Cap Screws are manufactured to ISO 14579 with a coarse thread pitch of 0.45 mm. This page lists the controlling dimensions for the M2.5 size — head geometry, width across flats, matching spanner size — together with the clearance hole, tapping drill and tightening torque used at assembly.
M2.5 Dimensional Row (ISO 14579)
| Size | Drive size | A (mm) | t_mean (mm) | Length range l (mm) | Reference standard |
|---|---|---|---|---|---|
| M2.5 | T8 | 2.4 | 1.0 | 4~25 | ISO 14579 |
Spanner & Drive for M2.5 Hexalobular Socket Head Cap Screws
Drive geometry for M2.5 Hexalobular Socket Head Cap Screws is given by the row above; match the tool to the listed values.
Hole Sizes for M2.5
| Coarse-thread pitch (ISO 724) | 0.45 mm |
|---|---|
| Through-hole / clearance (ISO 273 medium) | 2.9 mm |
| Tapping drill, coarse thread | 2.05 mm |
Tightening Torque for M2.5
| Class 8.8 (dry, ~µ 0.125) | ≈ 0.7 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 1.2 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 M2.5
| Tensile stress area As (ISO 724) | 3.4 mm² |
|---|---|
| Proof load, class 8.8 | 2 kN |
| Proof load, class 12.9 | 3.3 kN |
| Min. ultimate tensile load, class 8.8 | 2.7 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.
M2.5 Hexalobular Socket Head Cap Screws Weight
A steel M2.5 hexalobular socket head cap screws at the listed 425 mm length weighs approximately 16 g each — about 16 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.
Installation Tips for M2.5 Hexalobular Socket Head Cap Screws
- At M2.5 the joint is sensitive to over-torque — use a torque-limiting driver and check the head doesn't bury into a softer counterpart.
Mating Parts for M2.5
For M2.5, pair with a M2.5 hex nut (ISO 4032 / DIN 934) and, where used, a M2.5 flat washer (ISO 7089 / DIN 125A) under the head and under the nut.
Custom manufacturing · Made to drawing
Need hexalobular socket head cap screws in a size this table does not list?
This page covers M2.5 hexalobular socket head cap screws. Head form and drive can be specified to the assembly rather than to a standard: a larger bearing face, a security drive, or a socket sized for the tool already on the bench. Made by cold heading or warm forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
