My metal hacking needs are catered for by a Chinese multi-purpose machine (Chester 'Model B'), but I have to admit that the mill/drill head has hardly ever been used for the former operation due the lack of a proper tool holding capability (yes, I have tried using the drill chuck with predictable results!). I am looking to rectify this and am trying to choose between the 'own brand' collet chuck that Chester sells which needs a separate collet for each shank diameter or an 'ER' chuck where each collet appears to cover a small range, enabling one set to cover both metric and imperial. There is an ER25 set sold from Hong Kong on ebay shops which works out a good deal cheaper than the Chester set by the time you add in the cost of all the collets, but are there any drawbacks to the ER system - I've always though of a collet as inherently single size device.
I know there are some 'proper' engineers out there - any advice gratefully received.
Nick H