Summary

Watch made from 1921 pocket watch Hamilton movement and my 3D Printer.

The Trench watch was a type of watch that came into use by the military during World War I, as pocket watches were not practical in combat. It was a transitional design between pocket watches and wrist watches, incorporating features of both.

Instructions

40mm watch glass from eBay x2, for front and back
40mm (also known as 12s) pocket watch movement eBay, 17j is a quality movement and I paid $45 for a working movement.

Printed in PLA 20% infill
2 shells
.2mm layer height
standard PLA setting Simplify 3D:

Each Watch should include:
1x watch body
1x watch face ring
1x spacer for use with watch crystal, print as many as needed for use without crystal
2x watch link end 22mm
1x clasp
10x watch link 22mm, or as many as needed

To Snap together/apart the links, get two of the links at a 90 degree angle to each-other. You'll notice that the rectangular male 'peg' will match the female side with the notch.

Update:
Watch body and watch link end now have the same locking tab as the rest of the watch band.

Modern Trench Watch