…why not put your best foot forward?
One of fundamental principles guiding the design and construction of my T-Trak modules is this: show time is precious. Anything that makes show setup quicker and easier is worth some extra effort in the workshop. Hence, my adjustable feet.
Sure, plain carriage bolts work okay, and they're easy enough. A carriage-bolt head, however, is really not designed for turning with your fingers. Nor is it something you'd want having direct contact with a fine-furniture surface (say, your dining table). Over the course of a few module builds, the pictured foot has evolved, and it works quite well for my modules.
The foot is made from 1/2" Baltic birch plywood. Unlike most plywood products, this stuff is all-hardwood (not pine or poplar at the core), and is made of many thin plies (not a few thick ones). Granted, hobby-sized pieces of Baltic birch are not a home-center item, and you probably don't need the 1500 parts that a full 5'x5' sheet could provide, but this material is used widely in cabinetry construction. We use it in the furniture shop where I work; I set aside any suitable offcuts (pieces only 2"-4" wide are fine) that appear in the scrap bin. Call around to woodworking and cabinet shops in your area and ask for small offcuts, which they'll likely let you have for cheap or free.
I lay out 1-1/4" diameter circles on the blank, with maybe an inch of space between them. Each circle gets three 3/8" holes at the edge, drilled with a Forstner bit, to serve as the "notches" in the finished part. The centers are countersunk with a 5/8" Forstner bit for carriage-bolt heads, then through-drilled with a 1/4" twist drill. Make sure you've got a smooth scrap of plywood underneath the blank when drilling, to minimize chip-out.
The individual feet are rough-sawed apart at the band saw. Don't worry about getting close to the pencilled outline, because the final shaping happens at the belt sander. I make a very simple jig with a 1/4" dowel peg, oriented parallel to the sanding belt's direction of travel. The part is placed on the peg, then gradually brought up to the belt and rotated against it until the pencil line is reached. The edges are deburred by hand with a piece of sandpaper.
After the parts are spray-painted with flat black, it's time for assembly. I build my feet with 1/4-20 x 2" carriage bolts and retaining clips. First the carriage bolt is inserted into the plywood foot, then the clip is zipped over the threads (I use a short piece of 3/8" steel tubing and a rubber mallet for this). A washer and nut are snugged tight against the clip, then removed, to draw the bolt head into the wood and press everything tight. To clean up any damage to the bolt threads from installing the clip, I apply a drop or two of oil, then run a 1/4-20 die down the length of the bolt. A square of 2mm thick black self-adhesive craft foam is applied to the bottom of the foot, and trimmed with an X-Acto knife, to provide a no-mar, non-skid surface.
Sounds like a lot of work, doesn't it? Don't be scared—each individual step is quite easy, and most of the job can be done in odd moments when you have some spare time. Making feet for a dozen modules is nearly as easy as doing them for just one, so make a big batch. The payoff for all this work comes at show time, when a few quick flicks with your finger levels the module in seconds. It's time to run trains!