i once saw a film where a guy in Canada got dropped off in the brush by a chopper and did a survival camp as part of his PhD thesis.he busted rocks to get tools to make the parts for the bow drill and said it was a all day process to get the thing together and working.he never let the fire go out for the month or so he was out and said it was so much work that anyone who had to do that would never forget his matches again.he was a pro,like the guy who did the Ikea fire drill or those "natives" i see in the "how they live" Anthro movies.i would suggest that if you want to get the knack on how to do this that you make the best set you can and try it out every day--every day..maybe while watching some mindless TV you can work the bow to get the idea of how much pressure you need to exert on the spindle--and so on--be a kid in a pre-modern world who needs to learn to make a fire and not a guy who is just fooling around to see if it will work,if you really want to use it as a survival tool.i also saw another film from Canada made in the 50's where a native guy takes nothing more than a big splinter of pine and works it--fast and hard--in a grove in a split open pine block and gets a fire.i assume he grew up learning how to do that so it was second nature.
sorry..another 1:30 AM run-on...maybe the best survival item for fire making would be a tiny surgical implanted sparklight stick you could cut-dig out of your leg when all else failed.