Knob & Thumb Screw Generator (Nut Trap, D-Shaft) STL
Design fluted, knurled or lobed knobs with round, D-shaft or screw hole with hex nut trap · free, no signup
See Knob & Thumb Screw Generator (Nut Trap, D-Shaft) STL in action
Free Parametric Knob & Thumb Screw Generator
A knob is one of the most frequently printed small parts and one of the fiddliest to model. Choose a diameter, height and grip style — scalloped, knurled, lobed, hex or plain — and the number and depth of the flutes, then pick the hole: round shaft, D-shaft (potentiometers and small motors), double-D, blind hole, or a screw hole with a hex nut trap for M3 to M8.
The knob is built as a watertight solid, previewed in 3D and downloaded as STL, 3MF or OBJ. Clearance on the holes is adjustable for your printer. Everything runs in your browser.
Key features
Five grip styles
Scalloped, knurled, lobed, hex, plain round.
Shaft holes
Round, D, double-D and blind.
Nut trap
Hex pockets sized for M3–M8 nuts.
Printer clearance
Adjustable hole tolerance.
How to use it
- Set diameter, height and grip style.
- Pick the shaft or screw hole type.
- Adjust clearance.
- Download the knob.
Worked example
Example
A 30 mm knob, 12 mm high with 8 scallops and an M6 screw hole gets a 10 mm across-flats hex pocket 5.4 mm deep on its underside.
Who uses this tool
Electronics hobbyists
Replacement potentiometer knobs.
Workshop users
Thumb screws for jigs.
Designers
Machine and appliance knobs.
Repairers
Replace lost knobs.
Tips for the best results
- Print upside down for the nut trap.
- Measure the shaft with calipers.
- Use 0.1–0.2 mm clearance.
- Use 4 perimeters for strength.
Common mistakes to avoid
- Using the nominal shaft size without clearance.
- Making the knob too small for the nut trap.
- Printing sharp knurls with a thick layer height.
Why use AZRS QuickFix?
It is 100% free, needs no signup and has no watermark or usage limits. The tool runs in your browser, so what you type stays on your device, and it works on phones, tablets and desktops. New tools are added every week — bookmark this page or browse the full QuickFix toolbox.
Frequently asked questions
Does it print without supports?
Yes, flat side down.
What hex nut sizes are included?
M3, M4, M5, M6 and M8.
Can I make a D-shaft hole?
Yes, set the shaft diameter and flat width.
Is it free?
Yes.