Glass dating

Post by **Cam** » Sat Oct 23, 2004 8:41 pm

After removing the glass from my '52 MM, I wondered if the glass was original or had been replaced at some point.

I had a look on the internet about the Triplex codes for dating the glass and I found that my glass (well I only checked the rear and the front two screens so far) has a dot above the R in TRIPLEX and a dot below the O in TOUGHENED.

This would date the glass as 2nd quarter (April/May/June) 19?2. My car is supposed to have been made in June/July 1952 so that ties in.

My question is, how do I tell the decade of the glass? It has a dot in the centre of the 3 X's in between the words TRIPLEX and TOUGHENED I don't know if this has any bearing? I can't find any reference to it on the internet so I just wondered if anyone knew?

I remember talking to Bill about the glass codes on OJO at the Website R@lly, but I can't remember the details!!

Post by **Cam** » Sun Oct 24, 2004 12:44 am

I have now had chance to look at the other glass in the car.........

Both rear side windows (2-door) have the same markings, as does the driver's and passenger's door glass. Which would suggest that perhaps it's the original glass?

The only confusing thing is that the quarterlight glass (on both sides) has a dot above the X in TRIPLEX and a dot below the O in TOUGHENED.

This would date the quaterlight glass as 4th quarter (October/November/December) 19?2. 3 to 4 months AFTER the car's production date?!? or I suppose 4th quarter of 1962.........

It confused me as BOTH quaterlight glasses have the same markings, which would suggest they had been replaced at the same time. If they were different then you could assume that they had been smashed in an attempted break in or something....... but I would not imagine that they had BOTH been smashed in a break-in.

Any ideas?

Post by **polo2k** » Sun Oct 24, 2004 10:19 am

maybe there was a bad batch of glass and they were changed

Post by **ian.c** » Mon Dec 05, 2005 8:32 pm

You can also date the lucas parts on your car , the distributor , dynamo and regulator box will all be marked like 2 52 or similar.

Post by **Onne** » Mon Dec 05, 2005 10:15 pm

Tell us more Ian! And Cam

Post by **Judge** » Tue Dec 06, 2005 11:58 am

Does all this mean that we will be seeing you in Concours Onne, along with Cam?

Post by **Matt** » Tue Dec 06, 2005 12:29 pm

Cam, i thought of something, prehaps the window frames arn't the original ones, they were swapped for a better pair by a PO and they left the glass in the quaterlights?

Post by **Cam** » Tue Dec 06, 2005 6:13 pm

Matt, that of course is possible, but I would have thought that the doors would have gone before the frames and if so then they would probably have swapped the entire thing, but oddly enough I think the doors might well be the original items. It's a possibility though isn't it?

Onne, I can't find the original article, but I have found this from an MG forum:
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TRIPLE ‘X’ Code.

Many of the older classic car veterans will know of the TRIPLEX glass code. TRIPLEX were the company the majority of UK car makers used to supply their motor cars window glass in the post war period. This glass is toughened and carries the British ‘kite’ mark. The actual etched in marks on the glass are the word ‘TRIPLEX’, with three ‘X’s in the centre underlined by the word ‘TOUGHENED’. Under that the kite mark might be placed. Specially toughened windscreen have the word ‘ZEBRAZONE’ where ‘TOUGHENED’ would be. This is a screen with a central ‘clear’ area when broken so the driver can still see through it.

The code is etched into the glass during manufacture by TRIPLEX. It assists in determining when the glass was made. This can lead to assisting to decide the age of a car, or more accurately the approximate age of the car. The two letters at each end of the word TRIPLEX, that is the ‘T’, ‘R’, ‘E’, and ‘X’, will have a small dot under one of them. These four letters equate to the quarters of the year; so T is for Jan, Feb and March; R is for April, May & June; E is for July, Aug and Sept; and X is for Oct, Nov and Dec. Both the words toughened and zebrazone have nine letters. The dot will appear under a letter indicating the year, No dot at all will be 1950 or 1960. The first letter which might be the T or the Z indicates 1, so it will be 1951 or 1961. Then the O or E will be 2, 1952 or 1962; then the U or B will be 3, and so on until the last letters of either D or E, indicating a 9.

So if a windscreen in a M.G. TD or YA/YB, or any other window, has a dot under the dot under the R in TRIPLEX, and another under the T in TOUGHENDED, ( or the Z in ZEBRAZONE), this would indicate it was made in the first quarter of 1951. So cars for approximately the first six months of 1951 might have those indicators. If the same dots appeared in the same places, but on a MGA or Mk3 Magnette, or a Midget, it might be a 1961 model, with glass from the first quarter. Try your own car and see if it works.

Post by **Onne** » Tue Dec 06, 2005 10:29 pm

I will go look right away!
And Judge, I'd love to, but I still have some minor things to do on then MM

So I checked my windows in the mean time:
A dot above the I in triplex(so above the I not below!, nothing there), no dots below toughened
So that would be early 1950. I'll do the other tomorrow