The M2.5 size of Socket Set Screws is dimensioned by ISO 4026 / ISO 4029 / DIN 913-916. The tables below give the dimensional row from the standard, the drill and spanner sizes that go with it, and the assembly torque per property class. The technical drawing on this page redraws to the exact values selected.
M2.5 Dimensional Row (ISO 4026 / ISO 4029 / DIN 913-916)
| Size | Pitch (mm) | Hex socket s (mm) | Engagement depth t min (mm) | Point diameter dp (mm) | End type | Reference standard |
|---|---|---|---|---|---|---|
| M2.5 | 0.45 | 1.3 | 1.1 | 1.5 | Flat point | ISO 4026 / DIN 913-916 |
Spanner & Drive for M2.5 Socket Set Screws
The hex socket for M2.5 Socket Set Screws 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 key gives the most feel when you are judging preload by hand; anything repeated across a batch wants a torque-controlled driver instead.
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
Set screws are rated to ISO 898-5 by hardness, because they work in compression against a shaft rather than in tension. ISO 898-1 excludes them, and a set screw has no head to preload against, so neither a property class nor a preload torque applies. Seating torque depends on the point form and the shaft material.
Installation Tips for M2.5 Socket Set Screws
- 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 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 socket set screws in a size this table does not list?
This page covers M2.5 socket set 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.
