To make this model, you will need

-A casio f-91W watch

-7 m1.6*4mm screws (Sometimes called glasses screws)

-The printed components

And a sheet of .5mm PETG plastic (found commonly at hobby shops)

A STEP file is included if you wish to make any changes for your personal model, or need to tweak tolerances. 

Total cost between the files and the watch is around 25 AUD or 16 USD, pretty cheap compared to a rare timetron for over $500!

The watch retains full functionality, all the buttons still work. It is no longer waterproof but I have worn it in the rain with no issue, just be careful!

https://www.seiko-design.com/en/museum-en/vol8-en/ The inspiration. 

The ideal form of this watch uses a vacuum formed face. You could use a flat face but with a 3D printer vacuum forming can be achieved by anyone! Look on youtube and you will find several tutorials for simple vacuum boxes that cost just a few dollars to make, or see my experience in this video (not a tutorial): 

Anyways, onto the build guide.  Its pretty simple!

Print your parts. I use PLA, .4mm nozzle, .12mm layer height, and about 25% infill. Support can be used for the “body” component. 

Basic layout of important parts here.

Dismantle your watch by removing the 4 screws on the back. You will need these, the rear metal case, the rubber seal and of course the watch face. You will also need to remove the band of the watch by using a pin to push the strap pins out. These will be reused for your new watch!

Assembly is pretty straight forward. The watch strap is transferred to the wings on either side of the case. These wings have a dovetail and need to have a small amount of superglue applied in to hold them in place.

Next install the buttons. There are 3 and all are installed in the same manner. I would recommend sanding for a very smooth fit but they should fit straight off the printer.

use 3 of the m1.6 bolts and screw into the buttons. These bolts will move back and fourth to accuate the switches on the watch. no functions lost!

There is a range where the buttons will work, aligning the screw heads like shown here will work but you could go about another mm tighter if you want buttons that protrude less.

Pull the buttons all the way out to install the face.

combine the bubble with the face and then screw the whole setup together with the other 4 m1.6 screws

Now you can install the rubber seal, the back of the case, and its done!

I lost two screws doing this so many times.