I designed some parts to secure the 1550 nm Amplifier to the breadboard. The amplifier has some slots made for a 2U 19" Electronics Rack, so I used these to attach to the parts I made.

I decided to try to use the water jet since tolerance was not too important, the parts I designed were the same thickness, and slots are annoying to make in the mill. This worked very well. The 1/4-20 pilot holes were a bit oversized (0.209" instead of 0.201" diamter) but this is well within spec. I had to tap the parts myself and then drill another hole on the mill.

See attached files and photos.