I have found a use for old ball point pens that don't work. I remove the ink part and use the housing to hold a size 6 or size 8 drywall screw after I cut off the head of the screw. Just screw the drywall screw into the end of the housing. When it gets dull just sharpen on a grinder. A 2.5 or 3 inch drywall type screw can be used as a center punch to mark where you want to drill a hole on a plate, then use a larger center punch to deepen the hole when ready to drill. Also these drywall screw scribers can be used to test the hardness of piece of steel instead of an expensive file.
