Here is my home made table swift.
The top of the swift has a lathed ornament that is bored 1/2" diameter, 1-1/2" deep and glued to the dowel rod end. Then there is a free turning ferris wheel held by a 1"x1-1/2" collar which is set by a counter sunk 1/2" wood screw. The bottom ferris is also free and adjusted up and down by the bottom collar with a threaded bolt.
Think of it as a series of X's created by brass rivets. There are 6 of these X's mounted to the top and bottom ferris wheels in a 360 degree orientation. Each one is attached to the top, then the bottom held by #18 wire in the ferris wheels.
Notice the ray fleck of maple in the X-sticks (squint a little harder). ;)
The ends of the X's that point outward are tied to 6 more X's with nylon string.
The swift is adjusted by the bottom collar and a threaded wooden bolt. This slides up and down to open and close the swift.
The clamp is a wooden block cut like a C with squared throat as seen. A threaded wooden bolt is used to complete the clamp. Tighten by hand. These bolts are first turned on a lathe, then threaded with a jig and router. The main shaft of the swift is 1/2" dowel cut on my Veritas dowel jig.
The bottom of the dowel rod is glued into the clamp.
The finish I used on the swift is 3 coats of 50/50 boiled linseed oil and turpentine. Makes wood smooth as skin and does not seize up moving parts. You can make these as fancy as you like and even make it more rugged. I would suggest leaving it light weight.
Antiques Road Show had a 19th C swift made of whale bone appraised for $12,000. :)
Enjoy.