I've been using TB to generate parts for some time but I'm not sure how accurate the data is against standards.

I usually refer to BS3692 for the metric sizes which is the standard quoted in Machinery's HB27.

Under toolbox BSI/ISO/DIN the data for an M16 nut gives the head height as 13mm but toolbox 4032 is 14.8 and 4034 is 16mm.

I've checked the web and still come up with 13mm head height. I know it's only 2-3mm but when you're tight for space and trying to keep every gramme out every little helps.

Where is the toolbox data taken from and is it correct?