Basses built with an extra-long scale length greater than 34 inches.
This is the biggest of the Audiovoxes, weighing in at a full 12 pounds, with a 36" scale. The neck is a Brazilian Cherry (Jatoba) floorboard over maple, with a straight cutout headstock. There are over 100 marker dots. The body is veneered masonite over solid plywood, with Danelectro-style Tolex binding. There are also strap buttons, this instrument can be played vertically or horizontally.
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This is a spoke nut version, for use at the neck heel.
Here is a variation intended to adjust at the headstock rather than the heel, although it would work fine there too. I substituted a 1-1/2" 10-32 SS cap-head bolt for my usual spoke nut and threaded shaft. It is captured the same way, in a drilled-out coupling nut with a ground-down hex nut. The rod itself is 48" 3/16 rod steel, bent back on itself. Both coupling nuts are grooved on the attaching surface to hold the round rod. This greatly simplifies alignment and assembly, and the cap-head bolt eliminates one solder joint. All parts from my favorite luthiery supply shop, Home Depot.
More: Double-Acting Truss Rod ...