Construction articles by G.A. Harding on making A compact micrometer boring head appeared in model engineer in Jun/Jul 1982.
issue 3684 & 3682
There is an article on making a holder for screw cutting inserts in the projects section of the Home Metals Shop Club site that may help
I just had a look at my cad model to refresh the memory and I found that in fact it does break through with the given dimensions and that I had moved it from .350" to .370" so it wouldn't break thru.
Looking at my assembly model moving it by .02" doesn't look like it will cause any problems