View Full Version : Boring Bars

08-05-2004, 07:58 AM
Can someone explain to me the operation of a boring bar on a vertical milling machine. I see them come in different sizes and indexable and such, But how to you set the size of the bore? Say you wanted a 27mm diameter bore, do you need a 27mm bar? Do the indexing ones have ranges of bores on one bar? Is there a holder that offsets the bar to any size bore?

08-05-2004, 08:17 AM
Use a graduated offset boring head. It has a slide which you offset to get your desired bore size. The slide is graduated so that once you have a known bore you can continue offsetting (usually using a hex key) incrementaly until you reach your desired bore.

08-05-2004, 11:45 AM
My Criterion boring head (45$ on ebay) has a dovetail slot and adjustment wheel in thousandths. You put it into the mill and find center on the bore, then adjust it out and cut.

I have been using a home made cutter, is the square bars the same as the round ones.

As you might have guessed I am no expert so take it at what it is.