Oops! I tightened my connector and it snapped off

From the FAQ at www.W5SWL.com of 17 August 2018

Some connectors are made to me tightened with a specific torque spec and some are hand tighten only.

If the connector has a knurled surface, it is a sure bet it is hand tighten only. If you try to use pliers on it, you may well snap it off or push the shell past the slip ring.

Connectors that have flat sides as if fitted for wrench "may" have a specific torque setting. Now that doesn't mean crank down on it till you just feel right, it means that to be correct you need to apply the specific amount of force the manufacturer tells you. Of course some do have those surfaces and don't have a specific spec, just be mindful if you don't have the specs don't over tighten the connector.

Some female connectors on equipment can be damaged if you tighten the male to much as it exerts to much push on the female jack.