Its not overly obvious in the hand drawn design, but the main point of the main plate is as follows:

• Host a printing wheel that has the letters on it
• contain a paper feeding mechanism
• Be solid enough to cope with the hitting and pressing of the paper

Because aluminium is expensive, I started prototyping in plywood, to make sure my assumptions were correct, and that it all fitted inside the jar

Even though I had the mechanical drawings of the motors, I hadn't allowed enough space to fit all the paper handling bits in.

The other mistake I had made was not accounting for the width of the metal plate that holds the solenoids. Having learnt from my mistakes, and making some tweaks, I finally milled the aluminium plate

You can see some scratches in the black gloss, note to self, always finish your aluminium properly.

Its starting to look really nice now.