One of the little helpers I made myself, is an adjustable drive centre:
The conical centre piece is made from brass and has a thread that fits into its counterpiece in the steel body. In this way I can adjust how far it protrudes, and therefore how much pressure is put into the 4 jaws.
It works OK, but if I ever make myself another one, I think I’d probably also put a spring inside, so that the centre provides guidance and then retreats under pressure into the body. Also, the 4 jaws are not ideal, they should have a much sharper edge on the driving side. One day…
Update (October 2015): I have used this drive centre a lot, and it has also driven me almost to insanity. By now I have a Steb drive, and a variety of MT2 drive centres, and since I have my new lathe, I can actually use them. Summary: if you have no other option, do it. However, if you do have a bit of money, the Steb centre in whatever form (MT2 or jaw mounted) is far superior. It is very unlikely I will ever use this drive centre again.