After much hemming and hawing , I decided I really DO need a boring head . But after looking at prices I decided to use up some of that round stock I've been saving . So I've now got a mandrel made of some 4140 , the body is mostly machined and only needs the dovetails cut and the lock screws drilled and tapped . I haven't yet started the slide ... both body and slide are made from some 4140-type steel that I got from scrap . I have to decide whether to buy boring bars or make my own . I have a piece of 1/2" 300-series SS but I'm not sure if it's rigid enough . I also have a small pile of triangular carbide inserts ... and I've already made a boring bar for the lathe that uses these . I guess I can make just one and see how it works before doing more . Hey , I got more time than anything now that I'm retired ... well , at least right now , that will change as summer approaches .