The Spacer is for 4 longer screws so it don't come out from the other side of the mount. I used 4mm M3 with the 1mm spacer, If you have 3mm then it should be fine without it
Requires:
Don't over tighten the screw for the adxl to the mount, it will strip
Alternately, just glue the adxl and don't use the 2 short screws or a dab of glue on the thread of the screw or uses flathead screw.
The author remixed this model.
adxl345 in an unconventional area