Hi all, I know Adafruit made this nice Arduino mechanical drawing: http://www.adafruit.com/datasheets/arduino_hole_dimensions.pdf (http://www.adafruit.com/datasheets/arduino_hole_dimensions.pdf).
But the hole in the upper left of the drawing, despite my best noodling, seems to be impractically close to the header to be useful in mounting the Arduino to an enclosure. Using M3-0.5 or UNC 4-40 screws, the screw heads simply don't fit next to the female headers.
Am I misunderstanding the intended use of this hole? Is it not meant for mounting the Arduino to an enclosure, but rather only as a hole to accommodate a standoff that would be fastened to a shield above the Arduino and fastened to the Arduino from below? Please forgive any mechanical ignorance that I may be exposing, I simply want to understand the design intent better. What are some examples that actually use that hole for a practical purpose?
the hole in the upper left of the drawing ... seems to be impractically close to the header
yes, it is. That's because they added additional header pins AFTER the mounting hole position had been fixed.
You might have luck with screwless standoff things like:
On my first project I used nylon M3 screws, but chucked them into my electric drill and filed down the heads to fit the tight confines of the Arduino board. I'd have preferred to use the screwless standoffs but couldn't find any locally (nor in fact could I find them online), whereas the screws were available at my local Ace Hardware.
Not sure if this is still useful to you but they are known as "PCB supports" or "PCB Pillars" (or 1000 other things probably), but i found them on element 14
Unless you are going to beat the poor thing to death, the 3 other mounting holes are more than sufficient.
i see this problem is actually having allot of answers already, yet i would like to share my experience:
do not try 4 bolts and 4 nuts, it does not work for that one specific hole... so what i did, like Paul suggested, is that you just use the remaining holes that have sufficient room. it did the job very will in my application (driving bot).
Alternately, you can use an M2.5 screw there. It fits the space and does the job!