Boring heads for the mill

[Highpower]

That is one of the differences I discovered between the "economy" models of boring heads and the more expensive units. I have a couple of 2" boring heads. One import (Taiwan) and one made in the U.S.

Notice the threads for the "lead screw" for adjusting the size of the cut.
The "import" model has a very course adjustment and is not marked on the dial what the divisions represent.

The U.S. version on the other hand has a very fine thread, and is much easier to adjust in tiny increments than the import version. And the dial is clearly marked for .001" per division.

The number of divisions on each dial are the same, but clearly the movement of one division on the import dial results in moving the cutter well over .001" (diameter). I have not measured it to see what the divisions actually represent. I only use it for rough boring cuts that don't need to be precise.