The KA is of the K series of Monroe calculators produced from 1921 to 1928, with the A meaning Automatic, that is, with an electric motor attached.
Ever been at a garage/boot/stoop/yard sale,...
These are some common tools used to work on this device. You might not need every tool for every procedure.
6-in-1 Screwdriver
Probe and Pick Set
Tweezers
Digital Caliper
Heat Gun
Mako Driver Kit - 64 Precision Bits