A socket cap screw, also known as a socket head capscrew, socket screw, or Allen bolt, is a type of cap screw with a cylindrical head and hexagonal drive hole.
| STANDARD - ASTM A193 |
|---|
| Grade | Diameter | Length | Material | Thread |
|---|---|---|---|---|
| B7 | 1/2 TO 1" | 1 TO 8" | ||
| B7M | 1/2 TO 1" | 1 TO 8" | ||
| B8 Class 1 | 1/2 TO 3/4" | 1 TO 8" | ||
| B8M Class 1 | 1/4 TO 1 1/4" | 1 TO 8" |