I have 2 sheet metal parts need to be joined together. when they are joined together, they form a rectangular box. approximate size L X W X H - 6" x 8" x 1.75". I am using #4-40x3/16" to hold them together and its perfect for me according to the various tests. At one place, the 3/16" is touching one of the internal parts. I do not have any other option other than using 1/8". the screw goes into tapping hole. this particular hole is exactly in the center according to the geometrical situation. the whole weight of the unit could be upto 3.5 lbs (maximum). at the ends and all other places, i am using 3/16" which is perfect. the 1/8" is taking all internal threads of tapped hole, but they are no threads protruding out. Will the joint be safe. My product will be always in static position. no dynamics involved. but what if product gets dropped from 2 meters height ?