There's been a lot of debate recently about whether it is wise to use a dremel tool to sharpen picks/points/screws. Some claim that it is too easy with the dremel to overheat and detemper the metal. Personally, I use a file to sharpen my picks and points, since it's easy enough to do, and I use a variable speed dremel with a fiber wheel to sharpen my screws, since it is easier to get a consistent bevel with the dremel than with a file.
It seems unlikely to me that it one would ever overheat the metal on a screw with a dremel and fiber wheel, especially with the dremel set at a low speed. I've been renewing the heads on my allen keys for years by grinding them on a bench grinder, and while I would never use the grinder on my ice gear, I have to say that, even with a fairly heavy grit wheel, as long as I dunk the wrenches in water every 30 seconds or so, I never overheat the metal.
So...are there any metalurgists/materials engineers out there who actually know how hard it is to detemper steel with a fiber wheel used at low speed? My screws show no discoloring, and stay sharp for quite a while (unless I hit rock!), so I'm fairly certain they're fine...given the controversy, though, I'd like to hear an opinion or two from someone who might actually know the answer....