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Chapter 4. Maple Mike: > The Clubholder Assembly - Pg. 118

Maple Mike 18" Cam laminate 1 Figure 04.05: The bits you need to cut from your freshly glued up 1 / 4 " x 8" x 18" blank. surgical tubing or some of the more industrial strength elas- tics available at sewing supply emporia. We've already parsed the subassemblies: clubholder assembly with club, trigger assembly, tension assembly, and chassis. Feel free to substitute your own thematic variations on any of these submechanisms at will. I dithered over the form factor considerably during this build. Theoretically, the dual-circle assembly to which the club assembly is attached can be condensed down to a single arm- like bar positioned as the radius of the hypothetical circular swing, which would eliminate much of the inertial mass from the equation and give improved efficiency. This improvement in efficiency comes, unfortunately, at a cost in club position adjustability that irritated me. Plus, the form factor didn't look anywhere near as eighteenth-century. [Figure 04.03] Do the math, and make your own decision. True to my nature, I opted for adjustability and proceeded accordingly. The Clubholder Assembly The clubholder assembly is the nexus point of energy transmission. There's a lot of oomph at work here, so building for strength is essential. The basic structure is a stack of wooden disks: two large ones separated by a 1 / 4 " spacer disk that serve as a secure fore-and-aft mount for the club assembly, and a thicker pulley disk that's offset from the center axis to provide a cam action to the tension of the bungee cords. [Figure 04.04] You're cutting 7" disks: cut your 1 / 4 " x4" stock into two 18" lengths, and butt-join them with glue and many clamps. Stop snickering. The subtleties of simple butt joints and the prominent role of glue-resistant battens in the successful execution thereof are documented in the Active Deskchop build log in Chapter 2. I heartily recommend perusing this short but informative sec- tion before you proceed. [Figure 04.05] Cure the glue overnight, then scribe and cut your circles. I started with 8" x 8" blanks stacked securely together with double-faced tape, then rough-shaped both disks simulta- neously on the scroll saw. Drill out the centers with a 1 / 4 " bit before you cut and finish the disks, but don't worry about the club-mounting holes. I realized well after the fact that they're better off being drilled post glue-up. [Figure 04.06 True up the circularity by threading a couple of inches of threaded rod through the center hole(s), with a washer, lock- washer and nut on each side. Chuck the rod into your electric drill or drill press: a quick spin and an artfully applied 80-grit 107