Thanks to those who have got back. Just to clarify, there is an adaptor which I have from MT4 to MT2 which allows you to use Myford collets, but it doesn't have the parallel bit or a shoulder so you can't mount chucks. I'm trying to do this on the cheap, so DC31K's suggestion was not immediately appealing, but I take Chris's suggestion, good point. I've added some pictures to clarify
This is not what I need, I've already got one!

needs the parallel portion and flange