Homebrew Drum Computer

Your target of the technology of 1963 fits reasonably well with my 1962 mainframe, it uses drum(s) for backing storage (holding program and data overlays to be brought into core) but I don't think that makes much difference to the drum itself, other than you may want more than one read/write head per track. Each drum looks to be about a foot diameter and about a foot and a half long. They spin at 5240 rpm on a vertical axis. The drum is made of aluminium and the manufacturers (International Computers and Tabulators) had a lot of trouble getting the surface coating right, trying all sorts of high tech methods until they found the most effective method was for someone to smooth it on by hand while the drum was spun at low speed, rather like a potter throwing a clay pot. They also had problems with the length of the drum, and had to logically divide it into two sections, each one with its own timing track and datum track. Hopefully if you keep the drum length small this will not be a problem for you. The drums are powered by 3/4 horse three phase motors with V-belts providing a step UP in speed from just under 3000rpm at the motor to 5240rpm. They do not need clean room conditions, they are not sealed, and even have a fan to draw cold air up from the bottom over the surface and out the top, or is it the other way around, I can't remember, the fan are currently removed anyway and the drums run fine in a rural environment (i.e. reasonably clean air, no coal fire smoke/smog/ diesel particulates) The drum sits within an aluminium casing which holds 244 (+some spares) read/write heads arranged in a helix so they do not need to be physically close to each other. The heads do not fly, and can be moved in and out using an Allen key, which is apparently done whilst watching a pressure gauge on an airline blowing air through a venturi in the read/write head, so that when the air pressure reaches a certain level, the head must be close enough to the drum because the drum is starting to impede the air flow. The steel screws have now rusted and seized in the aluminium but work just fine because if can't work loose they can't go out of adjustment. The drum is coated rather than plated, I know this because when certain machines used by the Home Office for security purposes were decommissioned, a friend of mine was required to dismantle the drums and wash the magnetic coating off of the drums before they (the drums) were allowed to leave the premises. The machines had earlier survived being blown up by terrorists detonating a bomb on the window ledge outside one of the computer room windows. They don't make them like that any more, tough as old boots! The same friend also worked on a serial drum machine with valves which was installed at a Carbon factory where the inside of the machine used to get covered in conductive fine carbon dust. It is amazing it worked at all. Another friend worked on modern electronic weighing equipment at a phosphate factory using bird droppings as the raw material. He was called in to one machine which had stopped working the previous day, and found a small rubber grommet had failed, the chemicals had got in and eaten the resin of the PCBs and the copper tracking was hanging loose inside the cabinet, it seemed that it had somehow been working in that state for some time because it would have taken some weeks for the resin to be consumed, so maybe this contradicts my statement that they don't make them like that any more. The 1MHz main machine clock is derived from the 250KHz drum timing track, so no need to synchronise to the drum except when switching between drums, or the two halves of a drum. The machine can also be run from a separate clock, though of course all drum accesses fail. For fault finding, it can even be run one cycle for every time you press a button, wonderful to watch data shifting through the registers displayed on the front console and see where your data is getting corrupted. Not so good for fault finding the drum, magnetic tape or other peripherals though. I hope some small part of these details might be of help to you, good luck with the project.