This section is from the book "The Boy Mechanic Vol. 2 1000 Things for Boys to Do", by Popular Mechanics Co.. Also available from Amazon: The Boy Mechanic, Vol2: 1000 Things for Boys to Do.
A pole can be fastened between two supports, posts, or in a door casing neatly and without fixtures in the following manner: The pole is cut 1/8 in. shorter than the space between the casings, and a 5/16 in. hole is drilled in each end, one to a depth of 1 1/2 in. and the other % in. deep, a coil spring being placed in the deepest hole.
Screws are turned into the center of the location for the pole in the door jambs, allowing one screw head to project 1/8in., and the other at least 1/4 inch.
To Place the pole in position, put the end with the spring in the hole on the screw head projecting 1/4 in. and push the pole against the jamb, allowing the other end to pass over the other projecting screw head until it slips into the hole by pressure from the spring. The spring will keep the pole in position. - Contributed by Ernest F. Dexter, Hartford, Conn.
Ill: No Fixtures That will Show are Required with This Fastening of a Portiere Pole