Commonly used open-ended wrenches are 7, 8, 10, 14, 17, 19, 22, 24, 27, 30, 32, 36, 4 1, 46, 55.

The corresponding thread specifications are M4, M5, M6, M8, M 10, M 12, M 14, M 16, M 18, M20, M22, M24, M27, M22.

Two: Allen key

The corresponding relationships are S3=M4, S4=M5, S5=M6, S6=M8, S8=M 10, S 10=M 12, s12 = m14-m.

Extended data:

1. The working ends of the two ends of the hexagon wrench are provided with hexagonal holes or dodecagonal holes, which are suitable for situations where the working space is narrow and ordinary wrenches cannot be used.

2. According to different structures, it can be divided into blunt wrenches, ring wrenches, dual-purpose wrenches, socket wrenches, hook wrenches, hexagon wrenches, torque wrenches and other special wrenches.

3. Wrenches are usually made of carbon structural steel or alloy structural steel.

Extended source: Baidu Encyclopedia _ Allen wrench