How to compensate for tool wear?

Let's say you want to cut a square boss on a CNC mill. You write your code (or use a cam program) to cut it to 1.000" x 1.000" . You then measure and it is 1.001" x 1.001" . Is there a method to take off the remaining 0.001" without having to re-compute all the tool paths?

I ask this since we were taught on manual mills in my machining class to work incremtally. Cut, mesure, cut some more, measure... until you get it within tolerance. You don't want to over-cut and ruin the part.

It seems to me that tight tolerence CNC machining is tricky since working incremetally would require several runs. Do you always cut the part oversize, measure, and re-generate the toolpaths for those features that are not to spec?

nope, you program toolpaths to the exact part size:
G1 x0 y0
x0 y1
x1 y1
x1 y0
x0 y0

then you add cutter compensation for the radius
of the endmill -example program:
G0 X-1 Y0 (RAPID TO PREPARE FOR CRC)
G1 G41 X0 Y0 D1 (TURN ON CRC DURING A NON-CUTTING
MOVE, SPECIFY TOOL'S RADIUS (D)
FROM OFFSET TABLE HELD IN CNC
COMPUTER- TOOL ADJUSTS TO THE
LEFT (OUTSIDE) OF THE PART LINE
(G41) ON ITS WAY TO (X0 Y0)

x0 y1
x1 y1
x1 y0
x0 y0
X-1 Y0 G40 (TURNS OFF CRC IN A NON-CUTTING
MOVE)
If the tool deflects ,is under/oversize the
tolerance changes , you're set . all you have
to do is open the offsets page of the control
and add/subtract to the size of the cutter.
You can also change the dia of the cutter,
"lie" to the controller to make the geometry
way over/under the toolpath. on a square boss
it's not much of a big deal, but engrave
something with calligraphic text...

After cutting the one part, uniformly oversize, just go back and change your tool table.

Some controllers have tool offset tables as well as tool wear tables, just add another 0.0005" to the wear table and the next one will be on size.

Keep in mind you may not want to comp that particuliar precut oversize workpiece the entire amount, if at all, due to spring in the machine, work and tooling.

Just anothe .02

if you can engage cutter comp at a point away from your part it may save some headache as far as gouging is concerned ex:
G0G90X-1.Y-1.G40
Z1.G43H01
G1Z-.025 F35.
G41X-.25Y-.25 F20. D01
Y1.F10.
X1.Y0
X-.25
X-.5Y-.5G40
G0Z1.M9
G91G28Z0M5
G28X0Y0M30