In the movie Alien, Ellen Ripley and Arthur Dallas both wear a watch made from two Casio F-100 watches. This includes a replica of the Casio F-100 watch as well as the watch surround.

The surround used in the actual movie props seems to be a flat, flexible piece; the surround model here is slightly different so it can be printed in hard plastic. This has the benefit of allowing it to sit better on your wrist than the movie version did, which tended to twist around on the actors' wrists.

Note that I do not actually own an original Casio F-100, but I did try to get my measurements as close a possible using photo references. If anyone has a Casio F-100 and finds that the watch surround doesn't fit, please let me know so I can adjust the dimensions.

Parts List

In addition to the printed parts, you'll also need:

• 2x Casio F-91W watches - Optional, for a functioning watch
• 18 mm resin watch band - You can use the band from one of the F-91W if you're using them.
• 4x 18 mm spring bars
• 18 mm strap - This goes between the two watch cases to hold them together, so it should be a strip of nylon watch band or something similar.
• Plastic for the screen - 1 mm acrylic works well. The artwork that goes behind the screen can be downloaded here.

Watch Movement

For a functioning watch, you'll need to remove the movements from the F-91Ws and trim them as shown here. You'll need to trim 1.5 mm from each side and 1.7 mm from the top. If properly trimmed, the electronics should fit snugly with friction and not need to be glued in. The watch back is press fit so the battery will still be replaceable. If you don't plan to make a functioning watch, you can print the solid body watch instead.

Trimming the sides is simple: trim the plastic with a craft knife along the existing gaps, and then cut the metal with a cutting disc in a rotary tool so it is flush with the circuit board. The circuit board on the sides should not be trimmed.

The top is easiest to trim all at once with a rotary tool. Remove the battery first, then reassemble the electronics without it to trim. Wear eye protection while using the rotary tool.