5. Preparing for Wrist Straps

5. Preparing for Wrist Straps

Create and implement a cutting tool for routing wrist straps / pocket watch fob. Create snap-fit strap bar for easier handling.

Build In Flexibility for Range of Sizes

Make sure to consider a range of materials and uses when selecting an option for wrist straps for your TIMESQUARE watch body project so that those you share your design with can easily source their own strap.

In the case of Circling the Square, I made sure that the opening could accomodate 3/4" straps as well as the 20mm straps I designed the watch around.

Overhangs and Support Material

While many of the CAM slicing tools (such as Slic3r, Skeinforge, and Cura) off support material printing even for single nozzle desktop printers, printed in the same material, narrow openings such as the one pictured proved too difficult to remove the support material, and the opening was too tight when support settings were not used.

Planning for support lead to a better, more flexible solution for the watch band -- snap-fit parts that work for pocket watch configuration as well.

Snap-fit Planning

In the interest of making use of support material printed in the same material as the watch body, I found I need to make a larger opening for the strap to loop out of the body. I modeled a snap-fit bar, to be held in place by the loop of the strap. A shorter bar of the same footprint can be inserted inside of the body of the watch for the use of a pocket watch fob. 

In view in this shot are the bar, a copy of the disk I used to make the snap-fit slot, and the version of the watch body prepared for this solution.

Printing Strap Tests

Working on an earlier attempt to route straps out around the outside of the case, I came up with this solution. Because I was focused on the part of the model OUTSIDE of the body, I didn't notice the serious mistake that might be clear to some of you in the middle of the frame: the plate that I shifted around now prevents one from inserting the electronics -- the notches of the PCB stop at the top of the strap bar.

While after the fact I felt this should have been obvious, printing out a test model made the issue immediately clear -- and this print further proved that the narrow horizontal slits were too small for support.
Last updated on May 04, 2015 Published on Jan 12, 2013