Xem Studiomeasured geometryLibrary › Hardware › Hex lag screws, 1/4 to 1/2 in (ASME B18.2.1): shank, head width and…
1/2 hex lag screw envelope
1/2 hex lag screw envelope: hex head 3/4 in across flats (basic) × 11/32 in high (basic) on a plain Ø12.70 mm (1/2 in nominal) shank, example length 3 in (76.2 mm) under the head (Xem's choice); no thread, chamfer, washer face or point
Exact dimensions. True size, no tolerance added. Threads are plain cylinders at the major diameter.
STEP STL free, CC BY 4.0 (credit "Xem Studio")
Dimensions
| size (in) | 1/2 |
|---|---|
| TPI | 6 |
| shank E max / min (in) | .515 / .482 |
| across flats F, basic (AFT) | 3/4 |
| F max / min (AFT, in) | .750 / .725 |
| across flats F (Engineers Edge) | 3/4 |
| across corners G max / min (in) | .866 / .826 |
| head height H, basic (AFT) | 11/32 |
| H max / min (AFT, in) | .364 / .302 |
| shank hole (in) | 1/2 |
| pilot, softwood III & IV (in) | 15/64 |
| pilot, medium wood II (in) | 5/16 |
| pilot, hardwood I (in) | 11/32 |
| pilot (Portland Bolt / Haydon, in) | 5/16 |
Let your AI pull this. Add
Set it up →https://xemstudio.com/mcp to Claude, ChatGPT, Cursor or any MCP client (free, no account, one minute) and it can look up exact sizes, mating fits and free STEP/STL from every chat.From the full sheet
Hex lag screws, 1/4 to 1/2 in (ASME B18.2.1): shank, head width and height, pilot holes + envelope models: every size, notes, mating features and sources. What are the head size and pilot hole for a 3/8 lag screw?