Tiller, how does it work

[xtrema312]

I am trying to understand tiller better just to know I guess, but also to understand how grip and finger locations affect how the bow shoots.  How does the tiller work?  I do understand that you want to tiller the bow so both limbs bend the same.  I assume this then makes the limbs both move at the same time in the same place or timed the same I guess I should say.  The most I have found so far is that split finger is tillered positive, which I understood as larger measurement from the sting to the fade out on the tip limb, and three under is tillered even.  What I don't understand is exactly why this is and how it works dynamically when the bow is shot.  I think I read that positive tiller is the top limb being weaker, but I don't get how that would be measured at the fade out.  Why is it different for 3 under vs. split finger?  What affect does the limbs being out of balance have when the bow is shot?  I assume that one limb bends more than the other, but what happens dynamically on release?  Does the limb with more bend get to the all the way forward on the shot slower because it has to travel farther or does it get there faster because of more load?

[scrub-buster]

I think with 3 under, you are drawing closer to the center of the bow.  With split fingers, you are drawing above it.  If you make the bottom limb shorter, you raise the center line up.  Or some people just make the bottom limb a little stiffer.  Just my simple thoughts

[Stiks-n-Strings]

It's really just preference I think Joe Weed aka Osagetree just tillers his bows. No fancy 3 under or split fingered, just a well built and well tillered bow. I tiller mine a little stiffer by means of a shorter limb on the bottom and have no problems shooting split or 3 under. I just try to get it bending good and even and shoot her in.

I ain't smart enough to put that much thinking into it.

Just my .02 cents and not really any help but I will watching this post I may learn something.

Stiks

[Pat B]

I'm with these guys. I just tiller my bows so they look right and keep my bottom limb stiffer. I think for 3 under a nock adjustment will help if some excess stress is apparent.
 I like to keep this as simple as possible. That's why I switched to wood bows to begin with.

[rogers]

How much typically on average will making your bottom limb 1" shorter than the top limb move your tiller?

[Pat B]

Removing one inch from both limbs(piking) will add between 2# to 3# and maybe more so taking 1" off one limb should increase that limb quite a bit but you can regulate that by removing wood. I prefer to make my bows symmetrical with the center of the handle the center of the bow and both limbs the same length. This helps me see tiller better. I just make the bottom limb a bit stiffer.
 Another option I have used a bit lately and not determine which limb is top and which is bottom but put a floppy rest at each end of the handle on opposite sides and flip the bow occasionally so both limbs get equal treatment. Seems to work pretty good. I did the Trade Bow I sent to Osagetree(joe) like that last year...hence the bow's name, "Flip Flop".

[Aznboi3644]

I dont measure tiller with a ruler.  I go by feel...I'll measure differences in brace height between limbs but thats as far as I'll go...simple

[John Scifres]

Unbalanced bows are inefficient.  They shock the hand more and are more difficult to shoot consistently.  Hand position on both the bow and the string helps determine the balance.

Find the fulcrum of the bow based on your bow hand position.  Balance the bend based on that fulcrum with the goal being to have the limbs return to unsprung position at the same time.

Find the center of the string based on your string hand position's middle finger.  Pull from there as you tiller on the tree.

Visiual tiller on the tiller tree or stick is only the beginning.  Shooting the bow is the real teller.  If a bow looks great but draws and shoots like crap, something is wrong.  

It's your job as the bowyer to figure out what.  It may be tuning, it may be tiller, it may be poor mass placement.