The surface usually has a grid of threaded holes which allow the components to be bolted down to fit the optical system layout.

A nut is a type of fastener with a threaded hole.

A turnbuckle is a steel sleeve with a central slot and a threaded hole at either end.

The cylinder is installed through the outside of the door and fits into a threaded hole in the side of the case.

To make certain, wait till the steam is coming up, then unscrew this air valve and pull it out of its threaded hole.

There was a bolt inside of the threaded hole that allowed for the entire mechanism to be raised and lowered.

Loose cores, also called pick-outs, are used to cast intricate features, such as threaded holes.

Two threaded holes are provided in order to lock the coupling in position.