[2009-04-21] Top from CD and lamp parts

This is a simple but attractive top built from a CD and a couple of brass lamp finials. I used a yellow colored Lightscribe CD-R, which goes nicely with the brass. If you have a Lightscribe drive it's easy to customize the inscribed design to make a personalized gift. Or you can use some other process to decorate the CD, like a conventional printed label or fingerpaint or whatever.

The point on which the top spins is a Servalite LP-1276 Brass Finial, with a 4/27 tapped hole. The odd tap size, which is 1 tpi from the common 4/28, is standard among makers of lamp parts, and probably was implemented to insure that you have to buy one of their expensive finials to hold your lampshade in place and can't just use a 4/28 wingnut or something. Interestingly, I was nonetheless able to use a short length of 4/28 thread cut from a dowel joiner to secure the finials in this design, and it all screws together without any problems. The softness of the brass and/or the error in the precision of the threads keep the 1 tpi from making much difference over short thread engagements.

The handle is a 2" brass "teardrop" finial that I got at the big orange store. The CD is sandwiched between two 3/4" OD black rubber washers with two 5/8" OD brass washers outside them. A third washer, which is invisible when the top is assembled and therefore can be of the cheap steel variety, serves as a bushing inside the center hole of the CD, effectively reducing its diameter to 1/4". Theres still a bit of wiggle around the center axis of the threaded rod, but if you eyeball everything in place before you screw down the finials the top will balance just fine.

last modified 2009-04-21