Have a look at the versachuck on The Toolpost website, not sure if the size you need is a common one or not, but the versachuck is a decent, strong chuck and will take a range of jaws from different manufacturers if you choose the appropriate jaw carriers.
I Got The Versa chuck when I binned my K10 I purchased the jaw carriers for £20 with The chuck it Will accept any carriers you wish and then any compatible jaws will fit but this does not include the axminster step jaws the vesa chuck I find is a better chuck it takes all I throw at it for the price you cant go wrong and it gets delivered next day
Regards
Bill
