Triplex date codes

[Mr Spigot]

I have seen a couple of posts giving links to date codes for Triplex windows and thought I would check those on my 1952 MM. I know it is pretty original, being in only two families from new, so they could well be original. While the year code seems to indicate 1952, the other dots do not seem to correspond to the tables at all. The quarter of manufacture is supposed to be shown by a dot above the T, R, E or X. Mine is above the I! There is also a third dot below the top X. The car was first registered in November 1952 and I was just curious as to why these dots seem to differ from those given in the date codes.

[geoberni]

I suspect that the unsual list that are found for dating the glass are a little vague as to when they started from.
They work for my car, a 1955, but when did they start...???
The system pre WWII was different and continued until 1950...(ish)

If you see this link, the pre-war system continued until 1949, however, the 4 quarters corresponded to the first 4 letters of TRIPLEX. T=1, R=2, I=3, P=4.
https://www.chicagolandmgclub.com/techt ... Series.pdf
Also the glass illustrated shows a dot under one of the middle 'x'. just like yours.

So my guess is that there may have been a bit of a crossover when they changed the system in 1950...Ish!

[Mr Spigot]

Thanks. That would make sense as the glass was probably made in the 3rd quarter of the year as the car was registered on 5th November 1952.