I have tried this , but not with "flint", but 2 pieces of iron pyrite, fools gold.
It will create a spark, but I gotta say, that it's pretty hard to do.
Have not been successful in actually getting much past the spark.
Also I have tried a lot of times to used the bow drill, and will continue to research local materials, to find something that will work, as I have seen it done at demonstrations also.
The demonstrator made it look easy, so I guess I'm just retarded, or lack the "secret", or maybe just lack patience.
Did try chucking up my "drill", in the Milwaukee, thinking that that would give me more speed, Nada.
So, I keep plenty of "Bic's" in every jacket, coat, bag, vehicle along with the fire steel, matches, fire starters, redundancy, redundancy, redundancy.

