I had to re-test my Canadian 1932 patent Tech as other sources were pointing this at 0.030" but mine is most definitely 0.025" ... until that is, I put a long bar/slot post-War cap (date code W1) on it and then it measures 0.030". That in itself is interesting because (well, because that post-War example of the first date code measures 0.025" iteself, but also) it is very easy to get mismatched caps/plates over the years, especially once these things have been through the hands of collectors who assemble better looking examples out of what they have without full knowledge of the details.
I don't have a point of authority on which cap should be on the Canadian 1932, but all of the examples on Mr Razor have the twin bar/slot cap (akin to the 1940s British) rather than the long bar/slot (as per the American examples). I believe I have the correct cap. Maybe the chap(s) who have measured theirs at 0.030" have mismatched examples? Anyone else with a Canadian 1932, can you check?
The other very interesting outcome is the Psycho. I have a B3 model, which puts it at 1956 yet the top cap is reminiscent of the cap from the 1970s (1966 on) which has the flat (no bar) underside. Unless, of course, it's a 1981 model? The fat handle would have been out of favour by the 1980s and would have been in vogue in the 1950s, so ... I'll take it as a 1950s razor but it does seen to be a bit of an anomaly with the top cap.
Looking at Mr Razor, both his examples of the Psycho (one from 1958 and one from 1973) have the same baseplate with the four corner cut outs to suit the 1970s style cap. Mine is even earlier at 1956. So, we were seeing the 1966 on style cap/plate out there a decade beforehand!
... and 1940s Bakelite Techs come in at 0.040"
