Pie Shaped Yarn Cutter Keychain

A keychain yarn cutter in the shape of a pie! I made these as swag for a Pi Day knitting retreat. They're designed to work with a 28mm rotary cutter blade, available at any quilting or craft store.

There are two versions: one which is glued together, and one which uses a small M3 screw to hold the top in place. The version with the screw is sturdier and better for daily use.

 I used printed the bottom at 0.25mm layer height and 0.12mm layer height for the tops so they would look nice and smooth.

Additional parts needed:

• 28mm rotary cutter blade
• glue or M3x8mm flat head screw
• Keychain split ring and chain

To assemble:

Glue version: 

The bottom part benefits from being printed alongside something else (the top or another bottom if you're making more than one) so that the post in the middle has time to cool between layers. 

Place the blade on the post of the bottom piece, add some glue to the hole on the top, and snap the pieces together aligning the yarn notch as you do.

Screw version:

Place the blade in the groove on the bottom piece. Place top piece on top. Insert one M3 x 8mm (McMaster-Carr 92125A128) flathead screw up from the bottom and carefully screw it into the top piece.

Both versions:

Attach keychain to top loop