The "self-drilling" (2 1/2" long with 3/16" shank) screw pictured below is the type that was used (among several others like it) to secure the top plate of a wood-framed wall to the bottom flange of a steel I-beam of 3/8" thickness. My inquiry here is whether once these screws have been used, as just described, if they could be expected to be re-used and the tip would still be sharp enough to drill through into the steel again or are the tips pretty much spent after one such use and I'd need to use new ones. Also would I necessarily need a power drill stronger than mine which happens to be an 18-Volt, 380-Watt motor cordless? [IMG]http://i207.photobucket.com/albums/bb153/sgull1/IMG_3644_zpsnx2sfn9f.jpg[/IMG]

I have hurricane panels over my windows. There tracks are mounted on the concrete walls with a threaded connection every six inches or so, the panels have circular holes at the bottom, the panel holes are lined up with the threaded connections then secured with wing nuts. When I had the house painted several years ago the painters put paint on these threads. So now the wing nuts won't go on smooth, some of them I need a plier to thread the wing nut on. I know I can probably clean the threads up with a metal wire brush...but I have like 20 windows so over 200 of these threads at the bottom, and another 200+ on top. I am looking for some quicker more efficient way to do this. I am thinking, if I can put together something with a matching female thread, that I can fit into my cordless drill or impact driver, I can just drive that onto the male threads and strip the paint off, then back out and move to the next, and should only take a few seconds to clean each thread. Thoughts? A bit holder, with a hex bolt into the bit holder, then the hex bolt into a long coupling nut? Glue together?