Step 7. Drill Holes for USB and Program Switch

The USB plug and the tact switch need holes so that you can access them when we reassemble the DRO-350.  Unfortunately, we cannot use the DRO-350 to machine the DRO-350 unless you have more than one so you'll have to do these the old-fashioned way (now how many cranks was that?).  The drawing below shows the dimensions of the two holes referenced from the screw hole in the upper right corner.  Note that the USB plug is square and slightly larger than the hole.  This is by design so that the top of the USB plug rests directly on the enclosure and forms a kind of sandwich between the case and the DPU-550 PCB.  This keeps the DPU-550 secure when you are inserting and removing the USB cable.