Really good instruction by Urban Scout, thank you!!
Some points from my experience:
most people tend to move the bow too fast…this provocs the powder to take a sausage shape with black colour–> the powder becomes coal before it reaches the critical temperature… Try to work more with differing the pressoure, rather than changing speed… also use the whole length of your bow… I use mostly a bow which reaches from my heart out to my finger tips of my arm extended to the side…
if the powder tends to become flaky or sausages you can first produce some fine powder by moving slower and when you have a enough of it you make a sprint which will produce some hot flakes which fall into the powder and ignites it… (because the black stuff cant hold the glow itself)
to test the quality of powder you have without having succeded to get an ember, you can touch shortly the powder with a lighter flame and see how well a ember developes…
Some wood which will not work with normal bowdrill-prodedure can become very functional if you first drill with a thinner handdrill and later when you are trough the board you can start with a bowdrill set. like this you use the downpressure more effetivly and turn it into friktion (imagine the eye of a hurrikan, where there ist no movement)
as urban scout mentioned, the smoke often changes when there is an ember… often the smoke moves up in a more centralized and denser shape. Often you will feel that the smell changes and it bites you in the nose…
like urban scout I think the shape of the spindle is much more important than loubrication (my eares,nose or hair are out in wilderness (HuuuHuuu…!!) mostly dry by ash and mud, so I dont have bodyfat to lubricate) I often point the upper part of the spindle like a pencil (remember the eye of the hurikan) if you need lubrication you can put leaves into the hand element (some work better than others)
If the tip of the spindel becomes shiny: ad pressure and sand or some of the produced powder
Its beautiful to learn wilderness skills… you always discover new things