It was a bit hard for me to extract if he identified the machine, but it's there: Thus, although the machine in the photos is very similar to the IBM 403, it

It was a bit hard for me to extract if he identified the machine, but it's there: Thus, although the machine in the photos is very similar to the IBM 403, it's not an exact match. After more research into IBM's various accounting machines, I conclude that machine in the photos is the IBM 405, an IBM accounting machine introduced in 1934 (earlier than that 1948 IBM 403 despite the larger model number).4 The IBM 405 (below) had curved legs that match the Abbott photos. In addition, the 405 has a narrower main cabinet than the 403, with bulky additional components attached to the left and right, outside the legs. This matches the narrower cabinet in the Abbott photos. (The 403 was an improved and modernized 405, explaining the overall similarity between the two machines.)