Ed, just a (I hope) helpful note about those, because just this week I took mine out for the first time (having bought it a year ago) from the brand new case to use it for boring a 4" hole. Mine is a 3" version and not Shars branded, but probably identical to yours, re-branded.

No problem I thought ,just use the shortest included boring bar in the horizontal position vs the vertical position to make the 4 inch cut. It was only about 1-1/2" deep in aluminum.

Nope. Though ten (!) carbide tipped boring bars were included of different sizes, all were right hand cutting. Fine for vertical boring mount, but not suitable mounted in the horizontal position. Not a single left handed bar was part of the kit.

Well, okay, I thought, just run the mill in reverse. Well, nope again. Y'see these aren't true R8 boring heads. They are generic boring heads, with a screw thread into an R8 taper adapter. That way the mfr can mount the same boring head to a number of different taper styles. Convenient for them, but of course now you can't run your adapted R8 boring head in reverse, because it will just unscrew.

So, Ed, you'll need to find left handed boring bars if you want to cut anything over 2". For mine that means 3/4" ground shank boring head bars -- good luck finding those. Of course I can make some, But now I'm making tools when I already spent a fair amount of money for a "purchased" solution. The boring head didn't turn out to be quite the boon to my shop I thought it would be.

I had a hole to cut. What did I do? Pulled out a cheap fly cutter, stuck a 1/4" lathe bit in it and quickly bored the hole, wondering why I had thought I needed a boring head in the first place.

The head was replaced in its aluminum case with its 10 right hand cutters and put back on the shelf unused.