MG T-ABC

I've just started out on my new season of my TC restoration. The first, and probably most difficult, item on the things to do list this year is to complete the stage 2 wood frame build as defined in TC Forever. I want to be sure that I have the curve of the top of the rear wheel arch wood right so I have gathered some measurements with the aid of some of the good people on here and I have also put the old wood wheel arch back on my car. I'm also hoping to get permission off a local museum to take some measurements off their totally original TC. Pictures and progress reports to follow, but for now, a quick question/observation:

Page 175 of TC Forever gives a dimension of 41 3/4" for the measurement across the inside of the body at 3.5" forward of the back of the body. Measurement off my old wood and measurements from two people on this forum gives a consistent answer which is 1/3" to 1/2" wider than this (8mm to 12mm). This makes me wonder a) if the dimension in TCFE is in error (should be say 42 1/8") and/or b) how accurately were these frames actually build in the factory - are all of these measurements within what they built to anyway?

At the moment, I'm planning on building to my original wood dimensions (1/3" wider at this point). Am I worrying too much about relatively small differences in my pursuit of accuracy?

Thoughts please...

these were all very much hand build things in those days and are known to differ! I would not worrie too much and make the best of it whatever suits you and your car best. May be other people think different on this topic?

I've been researching what the curve (as seen from above) of the TC body tub should be from the front of the wood that forms the back of the car through to the door pillar (i.e the wood that forms the rear wheel arch and the door pillar). Thanks to the people on here who provided measurements. Using these I've been trial fitting one side of the car. The following graphic shows measurements (in mm). The x-axis is distance from the back and the y-axis is the measurement to the centre line of the car (I used the centre line as a datum point as I have not done the other wheel arch yet). Double these to get the widths shown in TC Forever. The grapic shows I) the old wood from my car; ii) scaled measurements taken from a drawing in TC Forever; iii) Limited measurements taken from an original car in a museum; and iv) my test fit. Hopefully this all makes sense.

As Dirk points out, these cars were hand built. on that basis, I'm happy enough with my fit ( I think that I made a mistake in measuring one of my points as its off the line, but the curve on the actual wood is smooth)