IF you buy every thing for yew longs-Logs and bowstrings- and sell complete bows for street price from about 75 you make 1.8m as of Sunday, November,16.
yeah you'll definitely make money if you do it right, some people fletch things other than yew longs but those are really the only thing that people buy at mass amounts because they can alch them
If you've got time, do what Divine_god suggested. If you fletch maple (u)'s you don't have to string them (which is the most boring bit of fletching), AND you make a decent amount of money.
All you have to do is buy yew longbows (u) and buy the bowstring then sell them strung.. I made about 7mil from doing that. People think yew longs (u) don't sell but I never had problems buying them, just put up like 10 gp over med.