Hi Dave,Not sure how I managed to make them 2mm overlength as I measured them on a number of occasions during the build. I fully expected them to slot into place but on first trial the walls were clearly pushed out at the top. I think it must have been the cumulative effect of the solder on the square column pieces - ie 8 layers of solder, which I didn't factor in to the equation.
I've had the problem of solder thickness come up on some of my etches and i've had to deal with it there.
Incidentally if you click on the post number in a thread you get a link to that exact post. Saves people looking at the birdy hat pictures again .
http://www.rmweb.co.uk/community/index.php?/topic/16292-railex-2011/page__view__findpost__p__409839