Having been a bowdriller for many years, I've learned from others and my own experiments that there are a lot of ways to use a bowdrill other than the classic. For example, the notch isn't absolutely necessary. Here in America, there are many swampy wet areas where fires have to be built on log platforms. Turning up a coal on such ground is difficult. So someone thought this up. Use a fireboard somewhat thicker than usual, about 3 or 4 cm and at least twice the diameter of the spindle. Now, the hard part. Set your spindle in the middle of the boardwidth and drill about 2 cm into the board. (Or, you can cheat just a little and use an electric drill!) Save your chardust as you work if possible. You worked hard enough for it, you should get some good from it. Pack the chardust into the hole you just made. Now, with your tinder bundle ready, set your spindle right next to the first hole so that the edges just touch and drill.There must be a slight connection between the two holes. Your chardust will fall into the first hole and be ignited when you have bored sufficently into the second hole. To transfer the coal to your tinder, turn the board upside down over the tinder and strike the board sharply. This way, the coal is completely protected from the wet ground. When you have used up ("bottomed out" as we say) the second hole, move over and start a third hole. The second hole will now receive the chardust and be where the later coals form, still protected from the wet ground. This technioque is not as popular as the standard notched board because of the additional work involved in creating the first hole and the ignition isn't always as reliable as the notch technique. Still, it is worth experimenting with.
Second technique; Try a hollow spindle tip. Use your knife to bore out a hollow in the board end of the spindle.about 1/2 to 1 cm. You will find that you need somewhat less effort in making your coal. The reason is because the spindle is a rotating cylinder. This means the outside diameter is spinning much faster than the center, just as the tyre tread on an automobile spins faster than the axle because it has farther to travel. In turn, we see that the center of the spindle is creating drag but is not creating as much friction, heat and chardust as the circumference. So, if we eliminate the center by hollowing it out, the energy you put into the setup is used more efficently to create friction, heat and chardust. Afterwards, you will notice that the borehole is now convex rather than concave. If you use the same hole again, it will tend to return to the more familiar rounded spindle and concave hole as the surfaces wear, but the hole will likely be used up before that happens. You will also find it helpful to have a second spindle with a pointed rather than a hollow tip for starting new holes. The hollow tip doesn't burn in/start new holes quite as well as a pointed tip. I suspect this technique was developed from the handdrill, which in America is oftentimes done with a spindle that has a pithy center and a hard outer diameter. The pithy center is useless for forming the char and is often dug out leaving only the circumference.
If you folks find these ideas useful, I will list others in the future. Good Luck!