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Overview

The Rounded Knob is the default, ergonomic press-fit knob for the wired OSSM remote’s rotary encoders. You print two per remote and press them onto the encoder shafts for precise, comfortable control.
Encoder functions can vary by firmware and device (wired vs. wireless). For an overview of current knob behavior on the wireless RADR remote, see Wireless Remote: Quick Start.

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Features

  • Smooth, rounded profile for comfortable, non-slip fingertip control
  • Positive, tactile feel for fine speed and stroke adjustments
  • Designed to press-fit onto the wired remote’s rotary encoder shafts
  • Two knobs required per remote (one per encoder)
Prefer a different feel? Alternate knob shapes are available in the project’s “Non-standard” designs (e.g., knurled or tall profiles).
  • Material: PLA or PETG (PETG recommended for durability)
  • Nozzle: 0.4 mm
  • Layer height: 0.2 mm
  • Walls (perimeters): 3
  • Top/bottom: 4–5 layers
  • Infill: 25% (Gyroid or Crosshatch)
  • Supports: Yes (Auto)
  • Adhesion: Brim optional (2–4 mm) for small-part stability
  • Orientation: Print with the shaft cavity facing upward for best surface quality inside the bore
If your printer runs tight on press-fit features, reduce horizontal expansion (elephant foot compensation) or scale X/Y by −0.5% before slicing.

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Install

1

Prepare the part

Remove supports and lightly deburr the bore with a hobby knife or small round file.
The bore is clean and smooth; no support nubs remain inside.
2

Test fit on the encoder shaft

Align the knob with the encoder shaft. Do not force it—ensure alignment first.
Excessive force can damage the encoder. Apply steady, straight pressure only.
3

Press-fit the knob

Press straight down until fully seated and flush with the encoder bushing. Repeat for the second encoder.
Knobs rotate smoothly and the remote registers encoder turns and clicks.

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Troubleshooting

  • Lightly ream the bore with a 6–6.5 mm round file or deburring tool.
  • Re-slice with −0.5% to −1% XY scale or use a negative horizontal expansion value.
  • Warm the knob slightly (hair dryer) and press-fit while warm.
  • Re-slice with +0.5% to +1% XY scale.
  • Add a thin wrap of PTFE/plumber’s tape to the shaft as a temporary shim.
  • Use a tiny drop of removable (blue) threadlocker—keep it off the encoder body.
  • Increase support Z‑distance/interface layers.
  • Switch to tree supports or reduce support density.
  • Orient with the bore up to minimize internal supports.

Wireless Remote: Quick Start

Understand current knob behaviors and controls on RADR.

OSSM: Info Sheet (Ready-to-Play)

What’s in the box and remote basics for OSSM.

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Download files

STL: Rounded Knob

Download for slicing