M8 Cap (Acorn) Nuts (DIN 1587) are specified by thread size, length and head dimensions. The M8 row from the standard is reproduced below, followed by the drill sizes, spanner size and torque values used when installing this size.
M8 Dimensional Row (DIN 1587)
| Size | Pitch (mm) | Width across flats s (mm) | Width across corners e min (mm) | Total height m (mm) | Dome diameter (mm) | Reference standard | Notes |
|---|---|---|---|---|---|---|---|
| M8 | 1.25 | 13.0 | 14.38 | 15.0 | 13.0 | DIN 1587 | Closed-end domed cap nut, decorative / protective |
Spanner & Drive for M8 Cap (Acorn) Nuts
Drive geometry for M8 Cap (Acorn) Nuts is given by the row above; match the tool to the listed values.
Common Applications for M8 Cap (Acorn) Nuts
M8 Cap (Acorn) Nuts are commonly specified for general-purpose joints in machinery, fixturing and equipment frames.
Mating Parts for M8
Pair M8 with the matching M8 bolt or screw, plus a M8 flat washer where required to distribute load on softer materials.
When to Step Up or Down from M8
When the joint preload approaches the proof load of M8 class 8.8, step up to M10 class 8.8 (or move to M8 class 10.9). When the joint is over-specified, M6 often saves weight and cost without losing the safety margin.