Knob with Dial: A Fully Parametric Fusion 360 Design

Encountering faulty or damaged knobs on devices is an all-too-common experience. To address this issue, I have engineered a fully parametric Fusion 360 design that allows you to 3D print knobs tailored to a wide array of D-shaped shaft sizes.

Initially, I considered providing pre-generated model files for various shaft dimensions. However, upon gathering data from potentiometer and rotary encoder manufacturers, it became evident that the dimensions are rather arbitrary with no discernible standard. Additionally, you may wish to customize tolerances to better suit your specific needs, which would result in an impractical number of models.

How to Print the Knobs

I have prepared a PrusaSlicer project—Example Print LR2365.3mf—which contains my recommended settings. However, you're welcome to consult the table below as a reference:

1. For larger nozzle sizes, you may need to amend wall-size parameters. Always review the slicer output for any potential gaps in the print.
2. PLA typically yields aesthetically superior results, but it may deform over time.
3. Enabling "Avoid Crossing Perimeters" minimizes stringing inside the knobs, making post-print cleanup easier.

Dimensions

The above drawing shows the dimensions for the example print and serves to illustrate various components of the knob.

Fusion 360 Design Parameters

The Fusion 360 design offers granular control over key dimensions, potentially eliminating the need for post-processing.

General Guidelines:

• Only modify parameters marked as favorites. Parameters starting with an underscore are either derived or perform specific intermediate functions in the model.
• Disable "Automatic Updates," make your adjustments, then click "Apply."
• Consult the description field for each parameter's recommended range of values.
• Review the timeline for any errors after parameter changes.

Important Parameters

shaft_diameter, shaft_length, shaft_d_thickness

Enter the exact dimensions of your shaft here. These should be precise measurements, as the model automatically incorporates the necessary spacing and tolerances.

tolerance_index

This parameter defines the fit of the knob on the shaft. Adjust to make the fit tighter or looser. Each increment or decrement of "1" changes the spacing by 0.01mm. A value of "55" is a solid starting point for well-calibrated printers.

knob_diameter, knob_height, knob_angle

Control the knob's outer dimensions using these parameters.

spring_thickness, spring_knob_height

The "spring thickness" affects how thick the wall of the spring is when printed. The default value of 0.86mm works well with a 0.4mm nozzle. Adjust only if your nozzle size causes issues.

The "spring knob height" dictates the spring's force against the shaft's flat side, which can degrade over time when using materials like PLA.

dial_line_width, dial_line_depth, dial_line_offset, dial_line_angle

These settings control the dial line's appearance and orientation. The angle can be adjusted between -180º and +180º.

Explore More from Meti·kumi

Interested in my designs? Browse through my collection of 3D models:

👉 https://metikumi.com/3d-models/

Stay connected on social media for the latest updates and work-in-progress insights:

👉 https://metikumi.com

Conclusion

I have successfully utilized this knob design in replacing various knobs on different devices. I hope you find it equally beneficial. If you appreciate the design and find it useful, please consider rating it and sharing photos of your prints.

Happy printing!