I ran some experiments with my LMF Army firesteel.
Comparing the volume of sparks thrown to the striker the LMF firsteel comes with to the tools on a Victorinox Swiss Army knife (SAK):
the back of the SAK saw worked about 200% better than the LMF striker
the large SAK blade worked about 100% better than the LMF striker
the small SAK blade worked about 50% better than the LMF striker
a 3.5" piece of hacksaw with a squared spine worked 50% better than the LMF striker
the teeth-side of 3.5" piece of hacksaw worked about the same as the LMF striker than the LMF striker
the SAK Alox soldier awl worked about 50% worse than the LMF striker
The springiness of the saw seem to be an advantage. The awl was "hard to use" from the standpoint that it was very sensitive to the angle it was being scraped at.
ps: does anyone know why the hacksaw didn't perform as well as the file ? Both are springy. I ground the spine of the hacksaw square using a diamond stone – carefully (I'm sure it wasn't rounded). If anything, I expected more sparks from the hacksaw since it's probably a lot harder than the SAK saw.
pps: Does anyone have any experience lighting wood shavings without dried grass (etc). I couldn't get it to work. Would a mish-metal rod work any better ?
Update:
After getting advise from several forums, I tried the "back" of the Alox awl. (ie: used the sharpend edge, but held the knife in my left hand). It produced about 20% more sparks than the saw back – and only experienced a 1/4mm nick whereas the saw had a 2/3cm area that was "nicked up to the point of almost being rounded". The awl was also no longer sensitive to the angle it was held at. Apparently the original angle issue was caused by how closely I held the sharpened edge to 90degrees to the firesteel. The reduced spark volume must have been because it was at 75 degrees etc and not using the sharp corner as effectively as it could have.

