There are various formulas and ratios suggested for "good" notches, but maybe we first should look at what a notch on a bowdrill hearthboard is supposed to do.

Some ideas:

help keep the spindle from flying away
maximize wdod-to-wood friction
deliver friction-produced "dust" to one small area
deliver fiction-produced smoldering "dust" to one small area

These ideas, if accurate, suggest:

a relatively narrow notch
a notch that does not go into the bottom of the spindle socket
a notch big enough so dust will not be trapped in the notch

Given variables in spindle size, hearthboard thickness, size of "dust" produced, ease with which dust falls from the notch, and whether or not your setup is producing smoldering "dust,"
you may have to adjust your notch several times with any given pair of spindles-and-hearthboards before things work right.

You may also have to work on the business end of your spindle to get its shape and size to work well with your socket in producing friction, "dust," etcetera.

Thoughts?

I would love to see someone take a scientific approach to this a la Mythbusters and using differing dowels, bases and pressures, scientifically ascertain which woods are best suited as well as which woods are not suitable.
Anyone out there who has a drillpress and some time? I would love to see the results.
I'm just saying....

Should my spindle and fire board be of the same wood? I can get smoke for days. Just on top of the dust I can see where it seems to be charred and the board itself smokes quite a bit.

My first instructor told me to work until the smokes "wreathes around the spindle, not just comes up as one thread" if that helps.

Cedar on cedar should work.

The hearthboard should not smoke much if at all but I am not sure what the adjustment for that would be.

How wide is your spindle where it touches the hearthboard socket?

How thick is your hearthboard compared to the width of your spindle where it touches the hearthboard socket?

Is your bowdrill making squeaking noises [too slick from charring or lubrication] or a more raspy rubbing noise [good friction of wood on wood]?

Anybody you can go to that is decent with a bowdrill?

Spindle about 1/2", fire board about the same 1/2". I have gotten both sqeaky and raspy sounds, it's good to know raspy is good. Thanks for the additional info.

It might not help but I found the Arizona episode of Dual Survival very helpful with my own hand/bow drill firemaking. Dave had no end of frustration until he realized Cody's secret: you have to let the ember smoulder on it's own for a few moments before trying to add it to your tinder.

a good practice board is a cedar shingle, you can get a bunch for short money

In general yes they should be the same. But certain combo's of wood work well together.

Squeaky is bad. It means your spindle has glazed over and won't provide friction needed to make a coal. A quick fix is to drop a couple of grains of sand in there and that might rough up the spindle enough. But you may just have to rough it up a little with your knife.

If you do put a couple of grains of sand into the hearth to rough up the board and spindle remove the sand before you go full force into attempting to get a coal or you may find that the sand inhibits the process.