Stupid Question: Torque Angle Meter

[mf44]

OK, I'm only a hobbyist, and I've been just drawing little marks on bolts when I need to torque to a certain angle. I've got a few more involved projects ahead of me, so I figured it's time to use a real tool for this.

Can someone explain how a torque angle meter works? It looks like it goes in between the ratchet and the socket. How does it not turn when I'm turning the socket? Am I missing something?

Sorry for the dumb question...

 

[Dimitri]

Many use a bent L piece of metal to prevent it from turning ...

Another style uses either a magnet or a little clamp ...

But only the indicator disk is supposed to be stopped from turning, it is a two piece design. Between the indicating disk and the drive center of them.

Dimitri