I realized that I've never posted photos of using a bowdrill. Well here it is.
For the record this was done with a pine bough drill (yes, pine... it works no matter what people tell you, as long as it's seasoned) on I believe a saguaro root board, though I'm not positive. The handle there is a an elk bone Jess gave me for our dating anniversary a couple of years ago.
The secret is to get the motion really smooth before you go at it. You start by carving a tiny hole and getting everything to move smoothly. For example, this drill isn't perfectly straight so I had to carve a point at a slight offset and very pointed at the top or it would bump "thoompa thoompa" as it spun, using up my energy and wiggling unnecessarilly.
Note my hand position, it's wrapped around my left leg. This is absolutely key. The shin-bone helps to stabilize your hand so you can keep everything still enough.
Once it's burned in a little stop and cut a notch to center. The dust is going to build up in this notch, pack, and hopefully ignite
I don't have any pictures of spinning up the fire, it's just me so I can't work the camera at the same time. Basically go easy and get it smooth, speed up a little so you're getting dust. If you're sqweeking push down a tiny bit harder, just hard enough for it to stop squeeking. If the twine slides on the drill you can often push just a touch with your thumb on the twine. It's not in the picture here but the twine is attached with a constrictor hitch on the far end, and a clove hitch on the near end. This way I can get it at just the right tension when I start by adjusting the clove hitch. I then hold the clove hitch and if I need a touch more tension I'll push with my thumb sideways on the twine just a little. Once you've got some dust you might want to speed up a little. Suffice to say that smoking doesn't cut it. Keep going until the smoke is pouring out, or you can see a red ember. If the smoke is really pouring stop and take a look - if the pile of dust keeps smoking you've got it.
This particular board and spindle combination is interesting. I found that I HAVE to go fast. I can get a coal very very quickly out of this combination with lots of dust. The trick is that it makes dust SO fast that it's hard to get it hot enough before I just have yet more dust. So, you need to dump energy into it kindof fast. Each combination of woods will have a slightly different property this way. I've started enough fires at this point to say that the problem I'm noting with this combination is very rare, usually you just keep at it nice and slow and you'll just turn out little bits of dust, and eventually it will ignite.
Once it's ignited, I take that pile of dust and dump it into a tinder bundle. This one is dry moss that fell off a tree.
Hold it tight squishing it a little to make sure the tinder is tight against the coal. It depends on the tinder, some tinder needs to be opened, others need to be squished. Generally opening it when you make the bundle and squishing it a bit is what you want. Blow gently, then harder, then harder, your hands will start to get hot, keep going until it ignites. It'll go up fast, so be ready to put it in your fire and throw some more tinder on it.
And build up your fire!