hi mate...i have just finished 2 blades using nothing more than a hacksaw, 2nd cut file and a leckie drill. i simply got some o1 flat stock or about a tenner, and a brass door hinge for the pins. the oak i cut from dead wood in the woods here on the farm and it was all sanded down with various grades of sandpaper. cost me next to nothing, a damn site less than 30 for both blades together.
check them out here:
http://www.bushcraftuk.com/forum/showthread.php?t=74118
bit rough and ready but as i made them im really chuffed...and theyre razor sharp too.
i'll be keeping an eye on this thread, let us know how you get on...
cheers.