i have access to a lot of farrier's rasp/files probably 20 or so i'm not looking to sale them but would like a couple of very simple knives made.is this something that would be a fair deal for both parties? pm me if you are interested.i am in the frisco area

I have heard they are brittle, so make sure you get someone that knows what they are doing

Yes they are brittle as they are now. They have to be annealed to work them properly then heat treated and tempered back to get them at HRC 60 or below. Between a hardness of 58 to 60 they will hold and edge but aren't prone to being brittle. When I use a rasp for an order I differentially heat treat them so that the edge is hard but the spine of the knife isn't, that way if you get them in a bind they aren't going to snap the blade.

I hope that this doesn't come off wrong and I mean no disrespect but that's going to be hard deal to make with someone. Used rasp are fairly cheap as far as knife blade materials go and there is actually more time spent on them than there is making a knife from new quality blade steel. They have to be annealed first and then all of the rust removed before you can even think of turning them into a blade. That takes a while and is something you don't have to do with new clean steel regardless of the type steel you are using.
Used farriers rasp can be had at a price that ranges between $1 to $3 at trades days, estate sales and so forth.

no disrespect taken.i know a farrier that goes through rasps like i go thru underware bout every 3 weeks..i didn't know the value of a rasp so i had to ask.

In my experience, rasps are hit or miss. I've done 8 or 10 farrier rasp knives, and have had three that wouldn't harden. Today I had a man come by with two rasp blades for me to HT. I'd warned him ahead of time that there was a possibility that they wouldn't work. I also did a rasp blade for myself. Two out of three hardened well enough. The third didn't.

As you get better at knives, you'll learn to hate the uncertainty. If I spend time on a knife, I want to be 100% sure it'll turn out. As Mike said, rasps aren't too hard to come by.

If I'm using a rasp I'll heat the tang to non magnetic and quench it in water. Then I'll put it in a vise and see if I can snap it off. If it snaps off 99% of the time the rasp will harden. If it bends then it's not going to make a good knife.

I saw this done on the tv show, can't think of the series

I played with a couple of them, trying to make fire starters for primitive muzzleloaders to use. I've made a bunch of those out of files with no problem, but I don't think the rasps have a good carbon content, as even after I would harden one...it would hardly strike a spark from a flint. Without a good carbon content, I would doubt it could make a good knife steel.
I'm not a knife maker..just some observations I've made.