Functional Clapping Hands Baseball Cap Attachment

Overview

Bring one of cartoon history's greatest novelty hats to life! Inspired by the iconic clapping-hands cap from SpongeBob SquarePants, this model turns any standard baseball cap into a fully functional, wearable clapping-hands hat.

Materials

3D Printed Parts:

• 1x Hat Base Mount

• 1x Hat Backer Plate

• 1x Left Clapper Arm

• 1x Right Clapper Arm

• 1x Left Clapping Hand

• 1x Right Clapping Hand

• 2x Band Wedge Pin

• 2x Finger Pull Handles

Non-Printed Hardware:

• 1x Standard Baseball Cap (or any other hat you would like)

• 4x M3 × 12 mm (or 16 mm) machine screws + 4x M3 hex nuts (clamps the base mount and internal backer plate together through the hat crown)

• 2x M3 × 16 mm screws + locknuts for the arm pivots (or use the included 3D-printed pins)

• 2x Standard rubber bands (e.g., #32 or #64 bands, or doubled-up standard bands)

• Braided nylon cord, mason twine, or heavy fishing line (~1.5 meters total)

Printing Information

• I used PETG for all parts, but PLA may work better for the hands if you want a louder clap. 

Assembly & Rigging Instructions

1. Mount to the Hat: Center the Base Mount over the top button of your baseball cap. Mark four matching screw holes (three hole-spacing widths are built in so you can choose narrow or wide clamping) and pierce the fabric with an awl or soldering iron tip. Press four M3 hex nuts into the underside nut traps of the Backer Plate, place it inside the cap crown, and bolt the Base Mount down from above.

2. Assemble Hands & Arms: Press the angled oval tenon at the top of each Clapper Arm into the matching oval socket in the wrist of the corresponding Clapping Hand (add a drop of glue if desired).

3. Install Arms into Stanchions: Seat the left and right arms into the base mount clevises and secure them with M3 × 16 mm screws or the printed Pivot Pins. Make sure they swing freely and rest back against the outboard backstops.

4. Attach Rubber Bands: Drop one end of a rubber band into the outboard vertical slot on the Base Mount and push a Band Wedge Pin through the horizontal teardrop hole until the split barb clicks into place. Stretch the other end of the band up and hook it over the outboard pirate hook on the Clapper Arm. Repeat on the other side. The hands will now spring open into a wide "V".

5. Crossover String Rigging:

   • Tie String 1 to the inner eyelet of the Left Arm, feed it down through the center Pringle Guide Ring toward the Right side of your hat, and tie on a Pull Handle.

   • Tie String 2 to the inner eyelet of the Right Arm, feed it down through the center Pringle Guide Ring toward the Left side of your hat, and tie on the second Pull Handle.

6. Clap! Pull down on both dangling handles to snap the hands together with a loud clap; release to let the bands spring them right back open!