Eagle Excellon File not lining up with Gerber File

Hi All,

Sorry I’m running into a frustrating problem that others may have run into. My Excellon file doesn’t line up correctly with my gerber file. I have already scaled it (by 0.01) according to John’s Tutorial (https://www.inventables.com/projects/pcb-milling-on-x-carve) and I have confirmed there are at least 5 digits for the X & Y values but it looks like the placement is still completely wrong. I have tried rotating, upside-down, mirror and various combinations but nothing seems to work.

I do not have a problem when using the eagle FTDI file from John’s tutorial and was able to plot both in flatcam without any problems, it’s just a problem in the PCB I designed. So it seems like a setting problem in Eagle.

Above is a screen shot from Flatcam. The red dots are from the excellon file and the green is the top layer gerber file (each of the pads are through hole). The odd part is the clump of red dots in the bottom left hand corner that seem very out of place. Any help would be appreciated.


I was able to figure out the solution. It appears there are multiple problems in the tool path so I’ve included my solution below in case anyone else runs into this problem. The general problem is you have multiple drill sizes in the excellon generated file (this can be because the components you are using may have slightly different drill sizes specified).


Part 1 : In Eagle:

  • File->Run ULP and select drillcfg.ulp
  • In the drill size prompt (i.e. T01, T02, etc), leave the T value that you want and remove the rest. In my case I left T01C0.813 but removed T02C1.016
  • Save the configuration file
  • Run Cam Processor
  • In Device, select “Excellon Rack”
  • For Rack, select your saved configuration file (this will change all your components to that drill size)
  • You may need to adjust the drill tolerance. In my case I just used a tolerance of 100% to 100% (these were just my test values, I haven’t gone back to figure out the exact values yet).
  • Run Process Job

Part 2: Altering the Eagle File

  • In some cases the generated file may not be parseable by Flatcam. If you run into this parse error when importing into Flatcam, follow the instructions below.

  • Eagle generates two files: DRI File and the file you specify (this is has whatever extension you gave it and can be referred to as the DRD file). Open up the DRD file in a text editor.

  • If the first two lines of that file are similar to below (then you need to alter the file):

  • To alter the file you need to add the following lines above the % T01:

  • The T01C0.813 is my drill size, but if you have a different drill size just change it to be T01C. The M48 and M71 are commands that are required.

  • This is what the file will look like after the alteration:

  • Save the file and import into flatcam.

  • Also, after you have imported the file in flatcam, selected the file and clicked on the “Selected” tab, the scale factor may not be 0.1 so you may need to play around with the value. In my case, I had to use a scale factor of 0.254.

Hope that helps!


I was about to start writing G Code files manually because of this eagle Excellon scaling problem. I’ll try your solution tonight, thanks @Bala

I put together a little video explaining the manual editing of an Excellon drill hole file for proper importing to Flatcam. Specifically, I am using Eagle 7.4.0 and Flatcam 8.4.

Editing the excellon file allows the user to maintain full resolution and use multiple tool sizes.

Link to video

Hi there,

Actually it’s non-compliant output from Eagle. The FlatCAM Manual has a section specifically on how to import from Eagle: FlatCAM Manual: “Eagle How-to”.

I hope this helps!