Tool heights/offsets

[adventuremetal]

Ok, I asked this question a bit ago but I'm still stuck.  I'm new to CNC so forgive the novice nature of this question.  I've attached the part file I'm working on below.  So lets say that I set my tool heights to the top of the fixed jaw of my vice.  How do I go about getting my tools offset correctly to machine the pocket depth accurately after my facing op.  I know there is the option to change my G54 z to do that but as I understand it that shouldn't be necessary.  Any help would be greatly appreciated.

Roger

[Anonymous]

Adventuremetal, 

                              Normally when you are running a CNC Mill, there will be a code to engage Tool Length Compensation. For example, 

(Skim Face)

T1 M06

G54

G00 X-1. Y-1.

G43 Z0. H01 (Tool length Compensation)

With that being said, you would manipulate the wear in the control to accurately machine to a depth in the Z axis. Remember you are compensating the tool, not the part. For example :

If my pocket was .005 deeper than i was aiming for, i would put .005 in my wear. That lets the control know that the tool is actually .005 longer than it thinks it is. You could also change the geometry, but I do not do it that way.