Dimensional data for M3 Thin Hex Nut, Fine Pitch to GB/T 6173 / ISO 8675, with the drive and the installation notes for this type.
Values are taken from the governing standard rather than from a general machine-thread table, because this type is not selected on one.
M3 Dimensional Row (GB/T 6173 / ISO 8675)
| Size | Pitch (mm) | Width across flats s (mm) | Width across corners e (mm) | Nut height m (mm) | Reference standard |
|---|---|---|---|---|---|
| M3 | 0.5 | 5.5 | 6.01 | 1.8 | ISO 4035 / GB/T 6172 |
Spanner & Drive for M3 Thin Hex Nut, Fine Pitch — GB/T 6173 / ISO 8675 (Series 056)
M3 Thin Hex Nut, Fine Pitch — GB/T 6173 / ISO 8675 (Series 056) have a width across flats of 5.5 mm — fit a 5.5 mm open-ended spanner or socket. In tight access a 6-point socket on the 5.5 mm flats gives the most engagement per degree of swing. Where the joint is torqued to a figure, a click wrench is the only way to reproduce it across a batch.
Tightening Torque for M3
| Class 8.8 (dry, ~µ 0.125) | ≈ 1.3 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 2.2 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 M3
Nuts are graded to ISO 898-2 by the proof load the nut itself will hold (classes 04, 05, 5, 6, 8, 10 and 12), not by the 8.8 / 10.9 / 12.9 scale used for bolts. A class-8 nut is the correct mate for a class-8.8 bolt, and the joint is designed on the bolt, so no bolt-tension figure is quoted here.
Installation Tips for M3 Thin Hex Nut, Fine Pitch — GB/T 6173 / ISO 8675 (Series 056)
- Use a 6-point socket where access allows — 12-point sockets are more prone to rounding the corners on smaller sizes.
- Serrated flanges need to sit directly on the joint face. A washer between the two removes the bite and leaves an ordinary bolted joint that is believed to be a locking one.
- At M3 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 M3
Pair M3 with the matching M3 bolt or screw, plus a M3 flat washer where required to distribute load on softer materials.
Custom manufacturing · Made to drawing
Need thin hex nut, fine pitch in a size this table does not list?
This page covers M3 thin hex nut, fine pitch. Height and across-flats are the two most often changed — a thinner nut for clearance, a larger hex for a tool that is already on the line. Made by cold heading or tapping.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
