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    It was while assembling the mixer for our first customer, Dave Siddle of the De Lane Lea’s studio in Kingsway, that I discovered about tolerance. Not human tolerance, that is, but the tolerance of dimensions when you have pieces of metal cut to size. I had assumed that, if one ordered some pieces of metal, say, 2" wide and 8" long, that was that. I would lay out all the drilled front panels in place on the mixer frame, and then drill the fixing holes - using the holes in the front panels as a guide. Then, I would tap the support holes with a 4BA tap. The panels would then be removed, and the controls fitted, panels wired, and the knobs fitted.
    It was when I came to re fit the panels into the desk, that the problem reared its ugly head. I found that having screwed down about half the panels, that the position of the tapped holes were no longer underneath the holes in the front panels. In fact, as more panels were fitted, the problem got worse.