Planetary Spinner Knob for Thrustmaster TH8S – Print-in-Place Herringbone Gearbox

Shift gears – with gears.

The top 32 mm of this TH8S knob is a free-spinning crown with an internal ring gear. The sun gear is fixed to the knob’s axle, so when you spin the crown, four herringbone planets roll around it. It’s a fidget toy for loading screens and pit stops – and it’s still a solid, comfortable knob when you shift.

Features

• Print-in-place: body, crown and 4 planets in one print, no supports, no assembly

• Herringbone teeth keep the planets locked in – nothing falls out

• Crown runs on a 25 mm journal with a retaining ridge, so it can’t lift off

• Ø55 mm grip crown with flutes; total height 76 mm

• Uses the official TH8S DESIGN PIECE unchanged – screws onto the official adapter

Printing

• Prints upside down (top face on the bed) – already oriented in the 3MF

• 0.2 mm, 4–5 perimeters, 15 % gyroid, no supports

• Elephant-foot compensation 0.2 mm – important for the gears on the first layer

• Clearances: 0.35 mm between teeth, 0.4 mm on the bearing

• ≈ 55 g of filament

After printing

1. Hold the body and give the crown one firm twist. This snaps 4 small breakaway tabs that brace the body during printing.

2. Spin the crown back and forth a few times to free up the gears.

3. Mount the official adapter on the TH8S following Thrustmaster’s instructions, then screw the knob on.

Tips

• Print the crown and planets in a different color: use the part list in PrusaSlicer, or paint them for a multi-material printer.

• If the gears feel stiff, a drop of dry PTFE lube helps.

Credits & license
Remix of THRUSTMASTER: Official TH8S Gear knob files – the DESIGN PIECE is used unchanged, everything else is new. Designed with AI assistance (Claude by Anthropic). CC BY-NC-SA 4.0.