Seiko Wristwatch Caseback Wrench Set

Not just for Seiko but really any watch having 6 notches to unscrew the case back. Since I'm a Seiko nut, that's all I tried them on, but there's no reason why they wouldn't work for any watch with 6 notches. The sizes are basically the outside diameter of the case back in millimeters.

This collection of files is for case back diameters ranging from 32 to 37 mm, in 1 mm increments. If you need another size than included here, hit me up and I'll upload other sizes. Easy to do since the model is parametric.

There is a handy tray that the wrenches fit in by friction and they stay put nicely. It has holes for wall mounting and has a firm enough grip on the wrenches that they will not fall out.

My first version of this had plastic nodules for the working features and it was great, but the nubs broke off after just a few uses so I changed the design to use metal pins. The pins are 1.5mm diameter x 10 mm long. The holes for those pins will be printed and they should be snug for the pins. I used a watchmaker's mallet to tap them in and did not need any adhesive. The hole size in the CAD model is actually 1.75 mm, but like all holes, the actual ID comes out tighter when printed with an FFF printer. If you choose to print on an SLA printer, these holes may end up being too loose and you'll want to use some cyanoacrylate adhesive most likely.

Here is a link to Amazon for a cheap pack of 50 pins, more than enough to make a complete set of wrenches. https://www.amazon.com/dp/B0DHH6181P?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1

I printed mine without supports and went with all default settings on a BambuLabs P1S with 0.4mm nozzle. See the photo for how that turned out.

These wrenches work surprisingly well. They should be good enough to unscrew tight cases and tighten them tight enough to compress the gasket fully.