Your sheet-metal fabrication shop just -- might -- find this drawing to be a bit more "user friendly". However, you can use whatever you wish to use. The format is what your sheet-metal shop "expects" to see and the "language" used in the attached mechanical drawing is what your sheet-metal shop "expects" to read and understand. In addition, all of the dimensions shown within the drawing that PeterC provided are called "Chain Dimensions" and by the time you take into account all of the tolerances and whatnot, the hole on the farthest right-side would probably end up falling off of your panel.
In addition, depending upon wherever it is that you are located on planet Earth and the capabilities of your sheet-metal shop, in today's CAD-design world, lots of sheet-metal shops are able to take the attached SolidWorks file I have included here and directly make your metal part from it!!! You can do the same thing for an entire rack-mount chassis if you want to.
The actual 3D CAD-design file of the above image is attached to this message, but due to limitations of this forum, I had to rename the file extension in order to attach it here. So, all ya gotta do is rename the attached file > API -- 500-Series EQ Front-Panel - SolidWorks CAD-File.pdf < to finally read as the following >> API -- 500-Series EQ Front-Panel - SolidWorks CAD-File.sldprt << and that is the file you can send to your sheet-metal shop if they happen to accept these types of files.
GOOD LUCK!!!
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