When writing to me about the four keystones we needed to fabricate, Sean Adcock wrote "All I remember is that they were fraught with potential disaster ".
He explains. "However exact you are trying to be with 'sawn' voussoirs, imperfections creep in, even if you start off from both sides of the wooden former with everything parallel, a millimetre here and a 32nd of an inch there, and even though the voussoirs still might fit fairly nicely, and no-one can see any problems arising ,you might still get to measuring for the middle keystone, and the two faces you need to fit the keystone into are not parallel. One end is perhaps a sixteenth of an inch wider than the other, but you know the keystone has to be cut to fit, and there is NO wriggle room, and there will be no spare material available to make a replacement keystone. So then yes, it IS potentially a disaster."
Sean goes on to write. " For that reason, no-one was keen to attempt to do a keystone for fear of botching it up. But the four chisellers were given one each to do."
"Needless to say I was not one of them, in many ways my job was to create problems for others to solve - and hats off to John, Mark, David and Kevin. Each was just left to get on with it... and all the imperfections were perfectly sorted out."
Mark Ricard dressing one of the key keystones
David Claman - another key keystone fabricator
