PP9 shell for 6xAA case

thingiverse

This is a case that is the same size as a PP9 battery as used in older British radios, e.g. Hacker, Roberts, from the 60s and 70s. These are getting harder to find. Instead, 6 AA cells in a standard 3x2 holder fit inside and are held in place, if required, by a drop in baffle, which should by 56mm wide and up to 75mm tall. A piece of card for example. A PP9 battery snap will be needed for the top, one can be rescued from a flat battery or you can buy one and wire it inappropriately (i.e. reversed polarity). It is possible to attach the contact with a small M2 bolt and nut if you want. Use a washer on the back as the connection and disconnection forces can be quite high. You can use primary AAs but a set of 6 rechargeable, low self discharge, 2.5AH AA NiMH cells should last a long time. Note you probably want to print it this way up, that's because of the inter-layer bonding being typically a weak point in 3D printing. If you print it on its back, then it might split apart if you wedge it in with some foam.