[cctalk] Re: IBM Punched Card Equipment

On Sep 3, 2025, at 13:56, Brian L. Stuart via cctalk <cctalk(a)classiccmp.org> wrote: Apologies in advance to anyone who gets this multiple times. I know a number of you are on more that one of these lists. I'm looking for some information on a couple of the early IBM unit record devices, in particular the Type 512A and the Type 518. Ideally, I'd like to get the mechanical dimensions in enough detail to create a CAD model. The background is that I'd like to improve the model that I'm using in my ENIAC simulator and I'm involved with a school in Arizona that's working on a project to build a full-scale model of the ENIAC. There's a letter from IBM in the ENIAC archives that suggest the use of the 512A and the 518. So I'm pretty sure those are the ones they used, but I haven't really been able to find any details about them. We've found a fair amount of information on the Type 513, and from photographs, the punch used on the machine seems similar to the 513, but is smaller. Thanks in advance, BLS