Radiator lockshield · hand knob
Lockshield Knob
A push-on knob for UK radiator lockshield valves, so they can be set by hand instead of with a key. The slot fits the standard 7 × 3 mm spindle blade. Print it in Orca with the settings below.
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7 × 3 mmSlot, straight through
Ø30 mmGrip, 10 flutes
20 mmHeight
~8 gFilament
~45 minPrint time
Orca Slicer settings
Switch the Process panel to Advanced first; some of these are hidden in the simple view. Highlighted rows matter most.
| Tab | Setting | Value |
|---|
| Filament | Material | PETG |
| Quality | Layer height | 0.2 mm |
| Quality → Precision | X-Y hole compensation | 0.1 mm |
| Strength → Walls | Wall loops | 5 |
| Strength → Top/bottom | Top / bottom shell layers | 4 / 4 |
| Strength → Infill | Sparse infill density | 25 % |
| Strength → Infill | Sparse infill pattern | Gyroid |
| Support | Enable support | Off |
| Others → Bed adhesion | Brim type | No-brim |
| Speed | First layer speed | 20 mm/s |
| Filament | Nozzle / bed (PETG) | 235° / 75° |
| Filament | Nozzle / bed (PLA) | 205° / 60° |
Why these settings
- Hole compensation keeps the slot trueBasic printers make holes 0.1–0.2 mm small. Without it the 7 × 3 mm slot can be too tight to push on.
- Five walls carry the twistThe turning force goes from the blade into the slot's sides. Five walls make the plastic round the slot solid, which matters more than infill.
- PETG, because the valve gets hotThe spindle runs at radiator water temperature, 60–70 °C. PLA softens from about 55 °C, so a PLA knob should come off once the valve is set.
Fitting
- Pull the white plastic cap off the lockshield.
- Push the knob onto the flat blade until it stops on the nut below.
- Clockwise closes, anticlockwise opens. The ridge on top lines up with the blade, so you can count turns.
- Note the turns open on tape inside the cap, then refit the cap or leave the knob on.
- Free a stuck valve with a spanner firstA seized lockshield will snap a plastic knob whatever the settings.
- Too tight?File the slot lightly, or ask for a 7.2 × 3.2 mm version.