Fully 3D Printed Knife Prop W/ Built-In Sound Effects (Halloween Movie Inspired)

I made a fully 3D printed knife that squeaks when you squeeze the handle, giving the perfect sound effect to this Halloween prop! 🔪🔪🔪

I have been designing 3D printable squeaky toys over the last few months, starting with a TPU duck in collaboration with SpoolDesigns's launch of "The Squeaker!", a fully 3D printable squeaker.

When I realized the squeaker sounds like the sound effects in the Halloween movies, I knew I had to design a squeaky toy knife! Check out the video in the last step to see and hear it in action!

I modeled the handle in Nomad Sculpt and the blades in Autodesk Fusion. I used Bambu Studio to cut out the slot for the blade and the hole for the squeaker.

I present to you the steps to 3D print your own Halloween knife prop!

Enjoy!

1. 3D models
2. Knife handle & blade by Karen Chau Designs (that's me!)
3. The Squeaker! by SpoolDesigns
4. 3D printer and slicer*
5. 3D printing filament
6. TPU filament
7. PLA filament
8. Scraper/blade
9. Hex key (or other small tool for assembling "The Squeaker!")

* NOTE: These instructions are written for Bambu Lab printers and Bambu Studio slicer software -- the provided print profiles (3mf files) may be incompatible with other slicers.

Open the knife handle print profile from https://makerworld.com/en/models/747540

Slice and 3D print the knife handle in TPU on a textured plate.

Verify the TPU handle has no unintentional holes (from poor print quality). The TPU handle needs to be fairly airtight to provide enough air to the squeaker when squeezed. As a quick test, use a finger to cover the squeaker hole completely and try gently squeezing the TPU handle -- air should not be leaking out throughout the print.

Open a knife blade print profile from https://makerworld.com/en/models/747540

There are two options for blades. One of them has a shorter tang so it can fit on an A1 mini.

Slice and 3D print your choice of blades in PLA on a smooth/high temp plate.

Open the print profile from https://makerworld.com/en/models/579374 -- refer to the "Printing Instructions" section.

Plate 1 contains the tube and reed that form a squeaker.

Slice and 3D print Plate 1 using PLA on a smooth/high temp plate.

Follow the instructions and refer to the GIF under the "Assembly" section from https://makerworld.com/en/models/579374 to insert the reed into the tube to form "The Squeaker!"

See my bonus video in the last step of this project for supplementary visuals.

Refer to the "Testing" section from https://makerworld.com/en/models/579374 to verify "The Squeaker!" is assembled properly, or use my preferred squeaker testing technique:

Partially insert "The Squeaker!" into the squeaker hole at the bottom of the TPU handle (as much as possible without snapping it in). Hold the squeaker in place with one finger while squeezing the TPU handle quickly several times to test if it squeaks.

If it doesn't squeak, reread the instructions to make sure the parts were printed and assembled correctly.

See my bonus video in the last step of this project for supplementary visuals.

After confirming "The Squeaker!" works, insert it completely into the squeaker hole at the bottom of the TPU handle. It should snap in easily and stay in place.

Insert the PLA blade into the slot at the top of the TPU handle.

Now that you have the knife completely 3D printed and assembled, give it a few squeezes to make the iconic stab-tacular Halloween knife sound effects! 🔪🔪🔪

Enjoy! 🔪

BONUS: Here's a silly "GRWM" style short video to see and hear it in action: Watch on YouTube