I designed these encoder and preamp knobs in Fusion 360 to replace my aging knobs that have started going brown, which is a common issue with grey ABS plastics over time. They are a perfect fit replacement for the M-Audio ProjectMix I/O preamp/encoder/headphone/master volume knobs, but should fit most 6mm D-shaft encoders.

Note: The preamp knobs have a 2.5mm extended shaft that goes through the hole around the preamp shaft on the control surface for stability and dust protection. The encoder knobs have a -0.5mm recess at the base so that there isn't a gap between the knob and the face, which helps keep the dust out. :) 

Printed on: X1 Carbon

Plate: PEI Textured

FIlament: PLA

Nozzle: 0.4mm

Quality: Modified 0.12 HQ preset, 2 walls, 100% infill

Bottom surface: Concentric

Outer wall speed: 40 mm/s

Wall Gen: Arachne

Requires no supports, and no brim if you're using the textured plate. The smooth plate will likely need a brim and/or glue for good adhesion.

The 3MF includes all print settings I used. It has a single test print, a single colour plate, and dual colour plates for both the encoder and preamp knobs (which have level indicators). Note: To change colours simply select object mode in your slicer and set the knobs and level position objects to your preferred colours. The filament change for dual colour knobs occurs at layer #17 for those without an AMS.

I've enabled “X-Y hole compensation” of 0.08mm to ensure the knobs fit snug, without being hard to push on.

This number may need to be adjusted for your specific printer and filament combination. This setting was used on my X1 Carbon with Bambu PLA.

I strongly suggest printing the single one first, D-shafts are compression fit and every printer/filament combo has different tolerances.

Note: If you have a digital caliper, do a test print and measure the inner diameter of the shaft. It should be between 5.95-5.99mm. My measurement was exactly 5.95mm using a Mitutoyo AOS Caliper and they fit very snug but are able to be removed without any tools. :)

Example: If your caliper reads 5.92mm then 5.95 - 5.92 = 0.03, you will increase “X-Y hole compensation” by 0.03mm. (0.08 + 0.03 = set compensation to 0.11mm)

Example: If your caliper reads 6.05mm then 5.95 - 6.05 = -0.10, you will decrease “X-Y hole compensation” by -0.10mm. (0.08 - 0.10 = set compensation to -0.02mm)

For those without calipers:

If it is too loose (6.0mm or more): Decrease the compensation by 0.05mm. (0.08 - 0.05 = set compensation to 0.03mm)

If it is too tight (5.94mm or less): Increase the compensation by 0.05mm. (0.08 + 0.05 = set compensation to 0.13mm)

If it is still too loose or tight: Reduce or increase in smaller increments of +/- 0.02mm until you find they fit snug but are not difficult to press on.

Hope you enjoy,

Decyphar