Jack, your palm rock looks a lot like the piece of obsidian I'm using, dremeled out the little pocket...
My set is all cedar right now. First two or three times, smoke in seconds, kept it going a bit, let the ember, um, ember-ify, and started a few fires. Now, however, I can still get heavy smoke quickly, keep it going, but can't get an ember to save my life.
When I first started having problems I was getting "beard stubble" looking stuff, which I think meant I was pressing too hard. I'm back to pretty much dark brown-ish powder, but I just can't seem to keep that ember going. The drill is harder to keep spinning toward the end... I've made a number of shallow cuts along the shaft to increase friction, but not sure it's helping. Any ideas on what I'm doing wrong? It'll smoke aplenty, but when I remover the board the smoke dies off. It's weird. The spindle and hole are almost too hot to touch, but the embers either not forming or not staying together or... ?