Assembly

Cast bosses take less torque than the fastener chart says

AssemblyA356Other4/5 confidence

What we learned

What worked

Dropping M6 torque to 7 Nm and adding a thread insert where the joint has to come apart more than twice.

What failed

Chart torque straight into a cast boss. Threads pulled on the third assembly.

War story

Learned on a customer bench, not ours, which is the expensive way to learn it. The torque spec now ships on the packing slip.

Assembly conditions

Torque
M6 into a cast A356 boss: 7 Nm, not the 10 Nm the chart gives for wrought
Fixturing
Torque with the part supported under the boss, never hanging

Tags

4
assemblytorquethreadsA356

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Captured May 29, 2026