Fire Extinguisher Shifter Knob for Thrustmaster TH8S

"Fire Extinguisher" Shifter Knob – Thrustmaster TH8S

Designed specifically for the Printables Thrustmaster Custom Shifter Knob 

 contest.

The goal was to create a fun and immersive mini fire extinguisher shifter knob for sim racing, perfectly fitted for the Thrustmaster TH8S using the official screw-on adapter.

Prototyping & Design Process

• Prototype V1:

  • First ergonomic test: the grip felt too small and the knob was too short.

    

  • Fix: enlarged the model (+10 mm in height and +5 mm in diameter) for a much better grip during gear shifts.

    

• Prototype V2:

  • Internal thread issue: print supports were too hard to remove and damaged the internal thread.

    

  • Fix: fine-tuned slicer support settings for clean threads, enlarged the sleeve on the body, and adjusted the handle dimensions.

    

  • Another weak point: the joint sleeve connecting the main body and top handle was too thin, resulting in weak hold.

    

• Final Version:

  • Clean, functional thread: supports unscrew effortlessly.

  • The Thrustmaster adapter threads fully and securely into the knob body.

    

All Prototypes & Grip

Assembly Instructions

1. Adapter: install the adapter onto your TH8S shifter shaft.

2. Body: screw the extinguisher body onto the adapter until it bottoms out securely.

3. Handle: glue the handle onto the body, adjusting its orientation to your preferred cockpit angle.

4. Nozzle/Horn: glue the black cone onto the handle tip.

Print Settings

• Printed on: Prusa CORE One+ Gen 2 0.4 mm nozzle

• Material: PLA

• Layer height: 0.20 mm

• Perimeters / Walls: 5 walls

• Infill: 15% Gyroid

• Supports: yes for the internal thread inside the body, and light supports for the handle

• Adapter: 100% infill