Sorry to take issue with Mark P, but a rear toolpost is a boon. It seems to solve parting off problems for many people. This will probabl;y reignite all the theories as to why/how!
I was sufficiently impressed with the results from the one that I made for my ML7, that I made a four way one for its larger oriental successor, to carry a front chamfer and back chamfer tool, as well as the parting tool. It VERY rarely leaves the Cross Slide, maybe because of the chamfering tools, but wouldn't be without it.
Again, my advice is to mod the post, as a "once and for all time" job, in case you ever find the need to mount any other tool on it.
Howard