I've tried a few friction fire methods with innumerable failures. So, very well done.
I experimented with fire saw ideas with elder, smallish bamboo, and a bit of pine beading this morning. I am impressed with the basic relative ease of getting smoke if you rub something along a thin edge. The tricky bit seems to be getting enough heat into one place with fine black powder in that place to start a coal. Also the bigger the general dimensions of your materials the more robust, allowing you to put more force (body weight) into the effort. Split 1.2cm elder is just too flimsy.
I'm thinking that get the dimensions and positions and setup ideal and lots of practice and this would not be too hard a method. Certainly the videos on YouTube don't appear too much effort, but signs of being well practiced. Just give me a dry bamboo forest and couple of weeks.............
I found out that pine glazes so aftet the first time you use it, once it goes black and cools all you get is smoke and black dust. When I got fire with pine I got a large quantity of brown dust very easy going the first time, after it cooled all i got was hot sweaty and frustrated.
There seems to be lots to the technicalities of it, to be honest I think any wood will make fire if its in the right condition and will not make fire if in the wrong condition.
Also wouls like to withdraw this suggestion of gearing. Although it does work, its a cord killer and you are more likely to snap/melt/set fire to your string as your kindling, and if your using pine a new hole and shaving the drill gets a bit repettitive, maybe another wood if you're using steel cable !
i like the hand drill notches altman, I think for one it would allow more air intake and help the ember not be charcoal ie too black dust!