Years ago I had a set of standard Webbs remade to go on a Mk 8 KTT velo, this involved some skillful remaking of the the head yoke, when I collected them, they were a beautiful job, ace bit of work, and the guy told me the forgings involved had been shear tested to way beyond safety limits, looking around his well equipped but small workshop I asked how/where that was done.
About 1/2 mile underground was the answer, NCB workshops in a coal mine.
Of course we haven't got any coal mines left have we?
Thanks maggie and the EU