[cuz1007]

:Machine Dawoo V-15 twin spindle. Control, fanuc 16T.
Have a job that requires drilling a 2.125" hole in a flange. so I installed a 2.125 Ken. fixed drill. I thought the x geometry offset was x0 for the center line, but not the case. so after investigating, I discovered the the work coordinate page (g54) reads x19.531 so I input x-19.531 in the geometry offset page. and ran a part. It drills the hole exactly .200 bigger than 2.125 at 2.325 not a big deal since the I.D. of part finishes at 3.0 but how can I find the true center Line?

[zavateandu]

you mount a dial gauge with 0.01mm division and stick it with magnet or mount it on a piece with a hole to the spindle ,bring the tool with X0 command and put the clock on the drill and rotate the spindle around the drill.
the spindle will generate a perfect circle and your dial should read almost 0 in the X axis direction,if not you can easily move the X axis untill you read same value on X axis direction.
maybe you will have some deviation on the imaginare Y direction(if your machine do not have Y axis)that is perpendicular to X axis.
if your machine has Y axis ,it is easy ,you just move the Y axis and X axis in the direction you want to have a perfect 0 when you rotate 360 degreee the spindle.
after you are finish,just copy the X axis machine value to work**** page and for Y axis you have to reset it by parameter 1815 APZ making it 0 and 1 again.

if your machine do not have Y axis and you have some deviation on the imaginary Y axis that is perpendicular to X axis ,you have to rotate mechanically the turret by releasing the screws from curving coupling and hit easily with a hammer untill you read almost 0 on your dial.

this is a work for a service guy,so is better to call one or be assisted by one.
have a good day.