The ballast includes a threaded end like that on ordinary incandescent bulbs.
The bolt or axle has one or two holes drilled through its threaded end.
They often have solvent welded socket ends or female threaded ends.
Item one: is a brass pipe-bowl with a threaded end.
Two types of threaded end can be purchased.
Push the wire into the box so the threaded end of the clamp protrudes inside.
The threaded end is open to accept small button cell batteries, and another cylinder that screws on to hold them in place.
For pins that have a cross-hole in the threaded end a cotter pin can be used.
Try to blow air through the threaded end.
All consist of a threaded end, to which a nut and washer can be attached for the external load.