One of my other purchases at Ally Pally was a remarkably cheap 16 mm drill chuck. At that price I did not expect any sort of quality but I was surprised to find it runs fairly true and there is only a little bit of binding when the jaws are half extended so it is infinitely better than the one it replaces. The real problem with it was the key which engaged the chuck teeth far too deep in places. I had to grind the flanks of the key teeth and round off the tips before it would operate smoothly. It took a couple of hours but at a cost of £7-50 I could not complain.
Cliff Coggin Kent UK