Sarge, the blade is 5160. It takes a pretty good edge, was easy to work, and easy to heat treat. I heated the blade to non magnetic and quenched it in 135* oil, I repeated twice. I drew the blade at 375* for on hour twice.
Howard, the hell with the file order some 1084 from
http://admiralsteel.com/ . I would suggest 5160, but I don't know what you'd do with 20' of it

. If you are going to use a file make sure you anneal it. Heat it to non magnetic then stick it in a bucket of sand or vermiculite, make sure the entire length of the steel is covered.
You can use a hair dryer and a charcoal fire to do the annealing and heat treating (wood charcoal, not Kingsford

). If you order from Admiral you shouldn't need to anneal though.
As for any tips I can give you, buy a new Nicholson 12" bastard file from HomeDepot, you'll be surprised how quickly it removes material. The file will also keep things nice and flat.
For heat treat you will need to get a magnet, and some good dry gloves

. Heat the blade until the magnet won't stick to the blade, then put it back in the fire for a few more seconds, dip the blade in warm (~130*) quenching oil. Let the blade cool then check it with a file, it should skate along the blade, if it doesn't, heat treat again. You may have some trouble with old files though; some may not be good steel (at least the Chinese ones). That's about all the knife making knowledge I have gained so far, let me know if you have any questions, I am always happy to pool my ignorance or maybe even make up some bull shite for you

.
Making knives is a lot of fun, good luck.
Matt