M1.6 Hex Bolts (ISO 4014 / ISO 4017) are specified by thread size, length and head dimensions. The M1.6 row from the standard is reproduced below, followed by the drill sizes, spanner size and torque values used when installing this size.
M1.6 Dimensional Row (ISO 4014 / ISO 4017)
| Size | Pitch coarse (mm) | Width across flats s (mm) | Width across corners e min (mm) | Head height k nom (mm) | Nominal diameter d (mm) | Reference standard | Notes |
|---|---|---|---|---|---|---|---|
| M1.6 | 0.35 | 3.2 | 3.48 | 1.1 | 1.6 | ISO 4014/4017 | Fully threaded |
Spanner & Drive for M1.6 Hex Bolts
M1.6 Hex Bolts have a width across flats of 3.2 mm — fit a 3.2 mm open-ended spanner or socket. Prefer a 6-point socket over a 12-point: it loads the corners of the 3.2 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 M1.6
| Coarse-thread pitch (ISO 724) | 0.35 mm |
|---|---|
| Through-hole / clearance (ISO 273 medium) | 1.8 mm |
| Tapping drill, coarse thread | 1.25 mm |
Tightening Torque for M1.6
| Class 8.8 (dry, ~µ 0.125) | ≈ 0.2 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 0.3 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 M1.6
| Tensile stress area As (ISO 724) | 1.3 mm² |
|---|---|
| Proof load, class 8.8 | 0.7 kN |
| Proof load, class 12.9 | 1.2 kN |
| Min. ultimate tensile load, class 8.8 | 1 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.
Installation Tips for M1.6 Hex Bolts
- Use a 6-point socket where access allows — 12-point sockets are more prone to rounding the corners on smaller sizes.
- A flanged head is its own washer. Adding a flat one under it lifts the serrations clear of the surface they are meant to bite, which is the whole locking mechanism gone.
- At M1.6 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 M1.6
For M1.6, pair with a M1.6 hex nut (ISO 4032 / DIN 934) and, where used, a M1.6 flat washer (ISO 7089 / DIN 125A) under the head and under the nut.
Custom manufacturing · Made to drawing
Need hex bolts in a size this table does not list?
This page covers M1.6 hex bolts. Where the standard stops, the drawing takes over: fine pitches, left-hand threads, partial threading, and property classes above the catalogued grade where material and heat treatment allow. Made by cold heading or hot forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
