Bountyhunter,

Sure, my kids and I have done that many times. Actually, the way I taught then to do it was as if they had no knife. Stick the end of the spear in a fire. As it chars, remove from the fire and scrape the char off with a shard of a broken rock. Continue, and a point forms - the very tip burns faster than the shank. Eventually, a graceful but not--very-sharp fire hardened point emerges - time varies with species of wood. If you are making a digging stick, you're finished. If you want a pointier skewer, grind it on a large rock (easiest) or use a rock in your hand to grind it. All very simple.

Different species of wood give different results. Fiddle around with it - it's a purposely fun thing to do whilst sitting around an open fire. My kids have been doing that since they were 3-4 years old and they still get a kick out if it once in a while.

HTH,

Tom