dusty wrote:...Occasionally, when I loosen an allen screw I hear a loud snapping noise and some times see what looks like sparks when it looses. What causes the sparks. BTW, I don't believe I over tighten the allens. Am I wrong?
I frequently loosen and tighten allen screws (not necessarily on my Mark V] and the changeover requires turning the allens). Many times, I have had the same experience that you are describing, although I have never noticed the sparks. I have thought that it could be caused by a couple of different things. Keeping in mind that steel and aluminum work against each other, when it comes to corrosion, a small amount of corrosion could build up and when you loosen the screw, you break the corrosion loose, causing the loud snap. Now, as this makes a kind of sense (to me anyway), that will knot explain why I have also had steel to steel create the snap too; therefore, another thing that I have thought may happen, is that the screw gets compressed (the opposite of over-torqueing, where a bolt can get stretched to it's breaking point) between the threads and the item that the screw is tightened against. When you loosen the screw, you relieve the compaction and get the snap.
Well, these are just some possible reasons. Nothing to back them up, just something to think about.