Shear screw - photo

[Altair]

Shear screw.




Previously:

Specialized bolts for botched jobs - photo
Giant bolt head press - GIF
Making eyebolts manually - GIF
NASA fastener design manual
80 threads per inch fastener close-up - photo

[hemmjo]

Interesting, I had to look that up. In addition to security applications, they are also used for electrical connections, where the torque of the connecting screws or bolts is critical.

[bruce.desertrat]

For when you absolutely, positively never want to open that thing again. I also suspect that they could vary the torque required on the fastener by varying the shear part.

[sossol]

For when you absolutely, positively never want to open that thing again. I also suspect that they could vary the torque required on the fastener by varying the shear part.

You’re accurate on both counts. Honda uses these to attach the ignition module to the steering column. They only break off at the required torque for that screw.
I installed a new module in my Element because it’s the only way to re-key them (due to the immobilizer), then discovered that I couldn’t get the door lock cylinders off without a special tool that I don’t have, then had to grind the heads off of the new ignition module to reinstall the old one. There’s very little space there, so it was a massive chore.

Neil