Between centers boring bar

[Hopefuldave]

One word (ok, a paragraph) of warning! Be certain that the tailstock Centre is dead in line with the headstock axis, if it's off you'll bore a nice concentric but elliptical hole! I've once done this deliberately (lots of offset for an internal cam), a couple of times accidentally... A ball Centre at each end (driving the bar with a dog) lets you move the headstock centre out to increase depth of cut by adjusting its position in a 4-jaw, easy once you get the hang of it...