Jon,
I hope your not saving your custom Ops Libraries in the Mill_Inch.Operations Library.
When you go to save your Ops, you can give it a new library name. You dont want a MCam update to clobber your custom Ops.
In your Machine Group - open the Properties and select the Files tab.
Under Operation Library, pull down and select your library.
Hit the ! on the right.
Your in Ops Edit. Change anything you want.
Sometimes it's almost easier to re-do the operation, check it's operation and just re-save it. Then delete the old one.
Good Luck,
Mike Mattera
Tips For Manufacturing Training CD's, DVD's for Mastercam, SolidWorks, Inventor, G-Code Training & More
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