Removing wood and nothing happens is good... it's much better than removing too much and creating a hinge.
Experience is what teaches you
how much to remove at any time.
It's a balancing act... too little and the job takes for ever... too much and it's ruined.
Pretty obvious, the former is the option to go for, it's all about patience.
The 'no change' you think you are seeing is probably just a very small change. If it was an obvious change it would prob' be too much.
I always say take off half as much as you think it needs
.
The whole tiller ing process is one of teasing it back by successive approximation.
If it takes less than a few days to get from floor tiller to full draw you are doing it too quick. Never try and do it in one session.
I reckon increasing the draw by say 2" at the target poundage is enough for one session, even if you just take a break for tea and toast (or your equivalent regional snack
). It's easy to get 'tiller fatigue' where you can no longer see what you are loking at.
When in doubt, step away from the bow
.
Doubtless some will dissagree, but I've never broken a bow by going too slow.
Del
BTW What are you removing wood with? A cabinet rasp or scraper are prob' favourite at the tillering stage, but it needs to be a good sharp scraper to have any real effect. I tend to use a rasp and then clean up with the scraper