At ScopeRoller, I am always looking for a way to play Rockefeller. Switching from boring out cylinders of acetal to a round aluminum sleeve that bolts on to the tripod leg both reduces materials costs, labr, and made a more durable product.
We were making a set for the Losmandy 8 Lightweight tripod. These are a rectangular sleeve instead of a round one, because the tripod leg is square. The labor was substantially reduced. The sleeves being square are easy to locate in the drill press vise, easier to drill and tap, and the acetal part that goes in the end in which the casters sit is now a rectangle, easy to make exactly right sized with a planer, insteade of turning on a lathe. So I wondered: why are the sleeves for most of these legs round? Just because the tripod leg is round? The sleeve holds to the leg with three bolts. Going to a square sleeve means using four bolts which reduces the force required on each bolt, producing less damage to the tripod leg and less stress to the threads. Square tubes weigh slightly more and cost a bit more than round, and 4 bolts cost more than 3 bolts, but labor saving is substantial and the holes are more precisely located.
This morning, as I started gathering materials for an experimental set for one of my telescopes that the tripods that sent me buying a CNC mill could benefit from this as well. The Vixen tripod legs are rectangular: