Homebrew PCBs

The board house does not use the gerber file to drill your boards. In the
package, I suspect you sent them an excellon or NC drill file. This file can
be opened with a text editor like notepad and can be edited if it is not
correct. One would need to have an understanding of the excellon output to
do this.
-Mike

Actually the problem I had was more related to the pcb program creating wierd aperatures. Never had issues with Excellon files, but the dragging aperatures have created problems in the past. 

I never modify gerber or excellon, as it makes it pretty much impossible to backtrack through the design system. My only real need for gerber editing is multiup issues and fiducials. One of my guys used to go in a twiddle gerber, but after blowing $5000 on a small production run, we stopped that. In hindsight, it was coupled with the fact that we stopped inspecting films prior to release in order to save time. At least today, the tools are good enough that I've never needed to go back and inspect films and rely on the second party gerber tool for verification.

Thanks for all the good links, looks like I've got some research to do.
Ron


[Non-text portions of this message have been removed]