Parametric Nut Caps & Knobs System

About this generator

Parametric Nut Caps & Knobs System is a free MakerWorld customizer by PLAyful Prints that turns a metric nut, bolt or shaft size into a printable cap, knob or furniture foot. It is one OpenSCAD script that runs in MakerWorld's Parametric Model Maker, so you fill in a form instead of editing code.

You choose a size from M1 to M16 and the hardware the part has to fit: a hex nut, an acorn nut, a flat bolt head, a motor D-shaft or a splined potentiometer shaft. Then you pick a style: dome cap, TPU furniture foot, star, knurled, wing, daisy or T-handle knob, or a low cover for socket-head and flat-head screws. The form lets you set press-fit tolerance, wall and base thickness, knob diameter, skirt length, a chamfered or rounded top and an optional side hole for a grub screw. Since an August update the dome cap can also get a wider skirt that hides the washer, sized automatically or from a diameter you type in.

It has been customized more than 9,100 times since May 2026, and the author was still updating it in late September. It suits anyone covering exposed bolts on furniture, adding grip knobs to jigs and clamps, or replacing a lost knob on a potentiometer or small motor.

What you can make

• Dome caps for nuts and bolt heads
• Nut and washer covers
• Star, knurled, wing, daisy and T-handle knobs
• D-shaft and potentiometer knobs
• TPU furniture feet
• Socket-head and flat-head screw covers

How to use Parametric Nut Caps & Knobs System

1. Open the model page and click Customize
2. Pick the metric size and the hardware the part must fit
3. Choose a cap, knob, foot or screw cover and set tolerance and dimensions
4. Generate, download and print, using TPU for feet and flexible caps