I purchased this TR-606 used and it was broken and beat up. It was missing a knob and one of the pots was bad. After I replaced that pot, the original knob didn't quite fit correctly so I made these up instead.

There are two versions of the big knobs and the small ones. One of the versions has the indicator separated so you can print it out of ABS or something else and the other version is just one piece.

I printed them out of TPU so they would have a universal fit on the pots. I printed them on my Flash Forge creator with the following settings:

• 50% infill rectilinear
• 1.3 extrusion modifier
• 220 degrees for the first layer, 217 degrees for the rest
• 35 degrees on the heated bed
• 600mm/min base speed
• 4 shells top, 3 for the sides and bottom
• .2 primary layer height
• 1mm retraction @ 1200mm/min
• 30% outline overlap

I watched this tutorial on how to make gears. This helped me figure out how to make the knurled grip:

http://www.thesketchupessentials.com/creating-gears-sketchup-without-plugins-extensions-sketchup-quick-tutorials/