Paul,


Do you recall the size of the adjustable boring bit your friend used on
the Bridgeport?
For a two inch step I imagine the boring head couldn`t be much bigger
than 1 inch in diameter.
 I`ve seen lots on E-Bay for sale but most are two inches and bigger.

Doug in Japan.

The boring head can be much bigger than the hole.
The size of the head has little to do with it.
A 4 inch diameter boring head could cut a half inch hole.
The size of the cutting tool has more to do with it.
The cutting tool can be located anywhere from the center of the head out to
the max radius of the boring head. The whole idea of a boring
head is the radius of the cutting edge can be adjusted down to .001 or below.

Paul Lamar