A grinning soldier seized a countersunk ring and raised the trap-door.
Two holes are bored and countersunk for screws to hold the post and handle.
The taper bolts should be of steel, but those with countersunk heads may be of iron.
Holes are bored and countersunk at the places shown in the drawing.
Small carriage bolts are better than nails but the heads should be countersunk into the bottom with the points up.
On top the holder is spotted or countersunk with a drill to form a recess for the C-clamp.
Their heads and nuts are let into countersunk holes so that no part will extend above the surface of the pulley.
It is fastened on with screws, the heads of which are countersunk.
As this process reverses the hinge, the screw holes must be countersunk on the opposite side.
It consists of a steel shaft coned at both ends running between two countersunk bearings, one of which is adjustable.