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EGG HEADS

Construct an interlocking puzzle with 30 identical pieces. By George W. Hart

As a retirement present for Joe Malkevitch, a geometer friend who likes puzzles, I designed and built this 1'-diameter Egg Heads puzzle from ¼" walnut.

Many of my sculpture and puzzle designs require laser-cutting or other computer-guided fabrication technology to accurately produce intricate parts. But this design is simple enough that you can make the parts yourself with ordinary shop tools such as a band saw and belt sander.

Photography by George W. Hart

The ease of fabricating the parts doesn’t imply ease of assembly, however. After cutting out the 30 parts, you’ll find it requires all of your puzzle-solving skills to interweave and interlock them into a symmetric structure. Here are instructions for making and assembling your own copy.

1. Start with a paper template.

The template can be scaled up to be 11" long using

a copier, or you can download the full-sized PDF version from makezine.com/17/diyhome_eggheads. The shape fits diagonally on a standard 8½"× 11" sheet of paper.

I designed a simple egg-shaped head that’s easy to saw, but you can personalize the face of yours if desired. However, don’t modify the neck notch or the 90° notch at the back of the head, which are carefully positioned for proper assembly.

2. Transfer the template to clear acrylic. You could just trace the paper outline, but a more accurate technique is to do a hot toner transfer. Either print the template with a laser printer or, if you use an inkjet printer, photocopy the printed template so you have a toner-based copy. Tape it, toner side down, to the acrylic and warm it with a heat gun as

Make: 143