3D print a replacement knob that fits the shaft
Stove, oven, washing machine, guitar amp, potentiometer: knobs break, and spare parts are expensive or discontinued. The difficult part is the shaft fit — a knob that is 0.2 mm too tight cracks, 0.2 mm too loose falls off. FitPrint asks for the three numbers that matter and uses your printer's calibrated clearance.
- Common shafts
- 6 mm D-shaft (flat 4.5–4.7 mm), 6 mm knurled, 1/4 inch
- Measure
- Diameter, across-the-flat, depth
- Fit
- Snug: hole = shaft + 0.4 × fit gap
- Material
- PETG/ASA near heat (stoves), PLA elsewhere
What to measure
- 01Shaft diameter at the round part (calipers, outside jaws).
- 02Across the flat: from the flat face to the opposite round side.
- 03How far the shaft goes into the knob (depth rod of the calipers).
- 04Optional: knob diameter, height, indicator line position.
Prompts to start from
“Replacement knob for my stove: D-shaft 6.0 mm, 4.6 mm across the flat, 12 mm deep. 35 mm wide with grip ribs and an indicator line.”
“Knob for a 6 mm knurled potentiometer shaft, 18 teeth, 15 mm deep, 20 mm diameter with a pointer.”
“Washing machine program knob, D-shaft 6.35 mm with a 5.0 mm flat, 45 mm diameter.”
Frequently asked questions
Which filament for a stove knob?
Stove knobs get warm. PETG or ASA tolerate heat much better than PLA, which softens around 55–60 °C.
My printed knob is too tight — what now?
Tell FitPrint how much (e.g. “0.2 mm too tight”). It adjusts the shaft hole; or calibrate your printer once so all future parts are right first time.
Related
Updated · Generated parts are a starting point — always test-fit before relying on a part.