Keenserts vs Wire Thread Inserts: Choosing the Right Insert for Aluminum Housings
When a threaded hole in an aluminum or magnesium housing strips — or must never strip — engineers reach for an insert. The two dominant choices behave very differently.
Where wire inserts win
Coiled wire inserts distribute load across a long elastic thread and can even improve fatigue performance over a cut thread in aluminum. They need minimal wall thickness, install in seconds and cost little. For housings with adequate boss diameter and moderate torque, they are the default.
Where key-locking inserts win
Keenserts (keyed inserts) drive four locking keys into the parent thread, making the assembly resistant to both rotation-out and high over-torque. Choose them when:
- The boss wall is too thin for a full wire-insert thread pattern.
- The joint sees repeated disassembly, high shock, or service torque beyond 8.8 bolt capability in aluminum.
- A stripped hole must be repaired permanently without bosses or weld buildup.
A quick decision rule
Design for target bolt proof load and check the boss OD first: if a standard wire insert pattern fits, start there; if not, move to a key insert before thinning the casting. Toprecision stocks both families in inch and metric, and our application engineers routinely cross-check customer drawings against both systems before quoting.
