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
4assemblytorquethreadsA356
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5Captured May 29, 2026