yeah,stone tools was the only way too go...sure,flint,obsidian,jasper,agate,chert,basalt any sharp stone...even sand stone for smoothing it down...measuring tape..i would say no...i think it was just one of those thing where its just passed down through hundreds maybe thousands of years...if you look at the bowyers bible 4..and see Steve's drawings of ishi gear...and get a measuring tape and measure the nocks,shoulders of nocks,limb width,and so on...he was only an 1/16 to 1/8 off our perfect measuring system now...and he did it all by eye...its just what i think and i might be wrong...thanks for coming on to the site...john