Click a row to pin a highlight on it. Hex key and wrench sizes are always shown in the fastener's own units.
Socket Head Cap Screws — Inch (ASME B18.3)
Socket Head Cap Screws — Metric (ISO 4762)
- Counterbore depth shown = max head height (flush). Add ~0.5 mm / 0.02" to sink the head below the surface.
- Close fit: accurate location, little float. Free fit: easy assembly, ~0.1–0.3 mm of float for alignment.
Button Head Socket Cap Screws
Flat Head Socket Cap Screws
- Flat head dia. is the theoretical sharp-edge maximum; countersink to this diameter (or slightly over) for a flush head.
Inch flat heads are 82°, metric are 90° — they are not interchangeable in a countersink.
Hex Bolts & Nuts
Inch (ASME B18.2.1 / B18.2.2)
- #4–#10 rows are machine screw hex nuts. Metric DIN 931/934 wrench sizes differ from ISO for M10, M12 (and M14, M22).
Wrench & Socket Clearance
- Socket nose OD is typical, not a standard value: brands vary by about ±10%, thin-wall sockets are smaller and impact sockets larger.
Measure your own sockets for tight designs.
- Ctr-to-Wall is the minimum distance from the fastener centerline to an adjacent wall for the tool to fit:
socket = nose OD / 2 + 1 mm. Allow more if the wall is taller than the socket nose, because the drive end is often larger.
- Open-end wrench values are rules of thumb (head width ≈ 2.2×AF + 3 mm). A 15° offset head needs a
30° swing to reach the next flats (60° swing if the wrench can't be flipped).
- Across corners = AF × 1.155 — the minimum clearance needed just to spin the nut/head itself.