The design of the hands had to take into account the diameter of the cannon pinion and hour wheel and the height of the hands, taking into account the thickness of the dial and indices.
Because of the level of precision of the 3D printing process, the hole had to be finished using a reamer.
I tried to heat-blue the hands but could not get a consistent colour and therefore decided to give up on this method.
As it is a sport watch, I decided to add lume. It was difficult to have a nice lume when filling a recess in the hands because they then had to be polished, which introduced contaminants.
I modified the design of the hands to have a smaller slot for the lume, but that went through the whole hand, allowing me to apply the lume from the back and eliminating the need to polish the lume afterwards.
For the second version of the sport watch, I used a CNC machine to make the hands instead of 3D printing them.
To bevel the sides of the hands, I made a dedicated holder with a protrusion that could be held with a hand vice and stuck the hand on. I then used adhesive lapping paper stuck on a smoothed file.
