Hi Chris, I sort of lost track of this log, or I would have chimed in earlier. The most likely problem is work hardening. Your silver steel and most hard alloy steels work harden rather easily, and to anneal them, you need full heat, up past critical, and usually need many hours of continued warmth as it cools. I put a piece in my wood stove, and take it out of the ashes the next day. When you work with cutters made from the same steel you're trying to cut, you are set up for disaster, as the same temperature/pressure conditions that work harden the blank will anneal the cutters you are using. For what you are doing, I would suggest making the cutters out of silver steel, heat treat them, and draw a very minimum, just enough to keep the edges from shattering off from pressure. I would use a piece of free cutting steel for the cutter blank, something leaded, use plenty of cutting oil, preferably brown sulfurated, because of the wonderful smell, not to mention the effect it has on cutting free cutting steel. After you have the profile done on the blank, and you're satisfied it's right on both sides, then go through the work of cutting teeth, back clearance and all that, and when it's done, then case harden the cutter with casenite. I use this method for gear cutters, and generally quench from the case hardening in oil, and don't temper at all. That works well for both brass and aluminum gears.
I don't think you work hardened the blank cutting it off unless you got signals saying so, like a nice blue color, and smoke coming off the cut off tool and maybe some sparks. You can use silver steel or drill rod to cut silver steel or drill rod, however the hardness before heat treatment is such that it is very abrasive to its self, and very easily will anneal cutting edges, while leaving the rest of the cutter unaffected, and appear to still be hard, although the important edges are not. I prefer to use brass for gears unless they really need strength, and I normally grind a high speed steel cutter for steel gears unless I can afford a proper form tool. I prefer to use low carbon steel for cutters and case them, because they can be worked with a setup such as the one you're using, effectively, and they can be touched up with files and the like and stoned to perfection and then case hardened without changing their form. I always take full depth cuts, to eliminate the possibility of error creeping in during changing the depth, and getting off track, making a mistake of my own which puts things on the wrong end, or something like that. I hope this helps a bit. Phil Duclos has done a couple of write-ups on making tools for gear cutting, I expect they are in his book, I know I saw them in some of the earlier HSM magazines, and in one of the Projects books which later came out. Ta ta for now, mad jack