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Chapter 7. iBlow > Putting it all together - Pg. 209

MAKE: PROJECTS Eccentric Cubicle Figure 07.23: Cheap-ass ballpoint pen. Figure 07.24: Almost ready. onto the bare areas you masked off before finishing, then peel off the adhesive guard paper and position the reservoir onto that. [Figure 07.22] However, not now. Wait 'til you've finished the rest of the assembly The bubble wheel axle is a length of ¼-20 threaded rod. Use brass or galvanized steel; it's gonna be in contact with water, and rust is undesirable. We'll use a plastic bushing to shield the axle and reduce friction. Rummage through your desk drawer and find a "budget" ballpoint pen -- sorta like this one. [FIgure 07.23] The shaft tube from this fine writing instrument has a ¼" ID, an OD of 21 / 64 ", 4 and has been injection-moulded from a quite obviously space-age plastic. Jolly good! A bushing! 4 21 64 "? / Drill out the axle pilot hole in the chassis to match the diameter of your pen shaft bushing tube, and cut it to length, extending ½" out from the front face and 5 / 16 " out from the rear face (the extra lengths are clearance standoffs). Drill out the pilot hole in the bubble-wheel drive pulley and tap ¼-20 threads, then measure and cut the threaded rod to length. You want to be able to thread on the pulley and wheel holder completely, with about 1 / 32 " clearance between the faces and the end of the bushing. Oy . . . again with the ridiculous dimensions. Specs like this are clear evidence of alien life among us, because no human in a position of Industrial Design authority would ever say "Tell you what, lads; let's make the diameter of this pen 21 / 64 ", because it's the perfect ergonomic compromise dimension for comfortable penmanship." 21 64 " is, in reality, exactly 10 G'cluurqs, a common dimension on Beta / Great Googly Moogly!! 5 The excitement is tangible as we enter the assembly portion of the build. Dress the wiring harness in the chassis with a few dabs of hot melt to hold the leads in the channel, and finalize the mounting of the USB port and power switch with two-part epoxy. If the drive motor sits less than firmly in the chassis, wrap it in electrical tape until it's a snug fit. 5 Yet another Frank Zappa reference: "Nanook Rubs It," from Apostrophe (1974), used denoting surprise and anticipation (and the impending injury of a fur trapper . . . whatever) although the term itself dates back to decadent and excitable early 50s bluesmen. Putting it all together Reticuli 4. Don't try to convince me that's a coincidence. 198