Getting A Few Things Straight
Last time, we tackled the job of cutting accurate fret slots on a fretless Aria Pro II Avante 6-string in order to turn it into a fretted bass. Now, I’ll make good on something I mused over at the end of the column: straightening the bent shafts of the Aria’s volume and tone pots. It seems that the bass took quite a whack, and with the instrument’s weight behind the blow, both posts kinked almost the exact same amount. As you see in the photos, these are concentric pots, which have two revolving shafts and require double knobs. The bent part was the center shaft of each pot. When turned, the knobs leaned like the Tower of Pisa.
Fig. 1 There’s the pride of Pisa—and look at all the wires! I soooo didn’t want to have to replace the pots. The less I touched the electronics—or even looked at them—the better. Besides, that’s way too much wiring for a little guy like me. After mulling it over for a few days, I came up with a possible solution.
Fig. 2a-2b To remove the knobs, I juiced up their rusted allen setscrews with a mix of machine oil and grain alcohol and applied it using small cotton swabs. The oil and alcohol aren’t entirely miscible and the alcohol evaporates fast, which leaves just the right amount of oil behind.
Fig. 3 I removed the pickguard to inspect the damage and found that only the inner shafts were bent. I hoped that I could “un-bend” the inner shaft by holding the outer shaft firmly and bending only the inner shaft. It was easier to make this repair with the pickguard removed, but since there wasn’t much “play” in the wiring, I couldn’t move the pickguard-mounted pots far from the instrument. I drilled a hole in a q" brass plate so that it would be a tight fit for the outer shaft. Then I clamped the plate to the bench so that it could reach out over the bass to hold each outer shaft. The brass plate held the outer shaft tight enough …
Fig. 4 … for me to bend the inner shaft with a levering bar, a bar with a hole drilled into the end that matched the inner shaft’s size.
Fig. 5 I fit the levering bar on the inner shafts, and with a little effort …
Fig. 6 … the posts straightened up nicely. I really lucked out—I didn’t have to replace the pots and mess with all of those wires.
See you next month!
