3/8 inch endpin clamp and preamp mount for O'cello

thingiverse

I printed the 1/2 inch rod O'cello remix and used a 1/2 x 36 inch steel rod, which is a little shorter than the 12 x 1000mm rod in the original design, with less rod protruding for an endpin clamp. I made an endpin from 3/8" aluminum rod, with a 12 inch section clamped to the steel rod with 2 hose clamps, and an adjustable 15 inch section clamped on with this double 3/8 inch rod clamp. The clamp tightens with m5x30 screws and wingnuts, and does not require supports to print. I tried adding enough clearance in the rod holes for the rods to slide freely, but on my printer with PETG the rod holes still needed to be drilled with a 25/64 inch drill bit, so you may need to scale the print up a few percent if you don't have this bit. The preamp mount clips over Zarlor's O'cello knee braces that use 2 aluminum 3/4 x 1/2 x 1/16 inch L-angle bars. The preamp I used: https://www.amazon.com/dp/B01JUCJGTE/ref=cm_sw_r_cp_apa_fabc_PBEZW0D3D2WNT8BS00FG?_encoding=UTF8&psc=1&tag=thingiverse09-20 The piezo pickup included with the preamp works with the remixed o'cello bridge, but the heat shrink over the pickup will need to be removed. One round hole in the mount is for the preamp ouput jack, the other round hole could be used for a panel mounted DC jack. I killed the preamp op-amp chip when I didn't check the polarity of my guitar pedal 9V DC adaptor, I forgot to check before soldering a DC jack with prewired red and black wires to the preamp red and black battery wires. I managed to unsolder the dead chip and replace it with a different op-amp.