Still trying to understand Neg/Pos Tiller

[Don Drake]

I am still trying to grasp the difference between negative and positive tiller.

From the Newbie's dictionary:

Negative tiller - The term used to describe the condition of a bow whose top limb is stronger than its bottom, apparent by measuring from near the dips of each limb to the string.

Positive tiller - A term used to describe the condition of a bow whose bottom limb is stronger than its top, apparent by measuring from near the dips of each limb to the string.


Does "near the dips" mean at the end of the fades where the limbs begin to bend?  

Do I measure the distance between the end of the fades and the string when the bow is braced?

Let's say that measurement is 6 6/8" on the upper limb and 6 5/8" on the lower limb.  Which limb is stronger?  Is that a positive or negative tiller?

Someone in another thread talked about balancing the bow at full draw.  He said to locate the point of the handle of the bow where the grip pressure is.  I grip my bows with the web of the thumb placed just below the arrow rest. I have little or no pressure on the handle from the bottom of my hand.

So I position the bow on the tiller tree so that the spot on the handle where my thumb web would be is resting on a single contact point.  I then draw the bow at the point on the string where my middle finger (I shoot split finger) would be to full draw and step back and look at.

Is the bow supposed to be swinging free like a teeter totter?  What am I looking for to see if its in balance?

Just trying to force all of this stuff into my hard head.    

Thanks.

[Roy from Pa]

Does "near the dips" mean at the end of the fades where the limbs begin to bend?

YES

Do I measure the distance between the end of the fades and the string when the bow is braced?

YES

Let's say that measurement is 6 6/8" on the upper limb and 6 5/8" on the lower limb. Which limb is stronger? Is that a positive or negative tiller?

Bottom Limb stronger. That is a positive tiller.

Tillering trees are good at first, but once you get the bow pulling to say 20 inches with a nice even bend, I feel it is better to not use the tree anymore and just pull the bow with your hand. Once you have the limb tips bending to about 9 inches, brace the bow to about 6 inches to finish tillering it. Pull it to 20 inches and shoot an arrow, see how it feels. Then increase pulling it a couple inches at a time while shooting it. The bow will tell you what it needs. It should pull smoothly straight back to full draw, and not have any hand shock when you shoot, if one limb seems to be stiffer and the bow tips in your hand, reduce the wood on the stiffer pulling limb.

[Trux Turning]

Don-measure at brace height from the end of your fades to the string. The stronger limb in your example is the 6 5/8" limb and has a positive tiller (top limb 6 6/8"). With split fingers, I like a positive tiller-three under I tiller to zero.

[Art B]

Don, you want to check your tiller once you have your bow braced up. With what you described, you have and 1/8" positive tiller. Bottom limb being stonger.

Measure your dips by running your tape back and forth to find the widest measurement. Do the same thing on the other end. That'll get plenty close enough.

Drawing the bow by hand and feeling for even limb strain is the best way to set proper tiller for your bow. Not on the tillering tree IMHO. Because if both limbs receive even limb strain at full draw, where neither limb is doing more work than the other, then this method will produce the positive/even tiller required for your shooting style.

This is my recommendation, I'm sure you will get others. Good luck with your bow making.......Art

[SEMO_HUNTER]

Originally posted by Trux Turning:
Don-measure at brace height from the end of your fades to the string. The stronger limb in your example is the 6 5/8" limb and has a positive tiller (top limb 6 6/8"). With split fingers, I like a positive tiller-three under I tiller to zero.

Man I'm glad you said that Trux, been trying to get that across with no success at all and heated up a few discussions from trying to explain that very statement. I shoot 2 under and strive to achieve an even tiller, it works for me.

[Don Drake]

Thanks guys, you really cleared things up. Learned a lot tonight.

[Roy from Pa]

Only sissy pants shoot 2 fingers under Elmo:) Ya only got 2 fingers left boy?

[SEMO_HUNTER]

Why use 3 when 2 will get the job done? Seriously, I just started doing that one day and it felt more natural than 3 fingers on the string and I get a cleaner release.
I knew a guy that shot a wheelie bow with no sights, drew 70+ and only shot with 1 finger and he was good!

[George Tsoukalas]

Well, the measuring method described above will work well with picture perfect straight staves as with board staves, for example, but I rarely work those. Subsequently,  I only care what the bow is doing at full draw. I aim for a bottom limb a 1/4" stiffer at full draw as shown through a mirror or digi pic. I ask my darling wife to take a picture for me.     Jawge

[Bowjunkie]

Yep, such predescribed tiller measurements at brace should NOT be adhered to in spite of how the bow acts, or looks, from that point on toward full draw. Those measurements, especially in selfbows, are largely inconsequential... or SHOULD be.

If you continually tiller varying selfbow staves to a predetermined myopic view at brace, you're not effecting the best possible tiller for all those bows... a few, perhaps, but not all.

People do it because it's easy, convenient, and popular... not necessarily because it's right, or best for the particular bow they happen to be working.

[Pat B]

I never measure a bow for positive/negative tiller. I check it out on the tree and look for the bottom limb to be slightly stiffer. I build symmetrical bows(middle of handle middle of bow)because it is easier for me to see proper tiller.
 Like George said I don't think checking a selfbow at brace makes any difference or have any value. Full draw with the shooter pulling the bow is the only true way to tell if a selfbow is well tillered.
  Also, I leave the handle area and the tips unshaped and unfinished until the very last. They are not needed to tiller a selfbow. That way I can make whichever limb is the stiffer of the two the bottom limb.

[Art B]

What measuring at brace does for me Pat, it shows me any tiller change/movement. Keeping a constant check with a ruler will show any tiller change either when drawing or shooting the bow in.

Once no tiller change is noticed after being shot-in, then I can be confident that it'll stay there providing for long term tiller health. Knowing the difference, if any, from one limb to the other, is a good way to keep an eye on the bow's tiller. Has a lot of value to me at least......Art

[PEARL DRUMS]

I dont listen to anybody that makes limbs of equal length, anybody that knows how to build self bows makes the bottom shorter.   :p

[SEMO_HUNTER]

Oh no, here we go again.      :D

[Roy from Pa]

I think I just heard a little mouse squeaken from central michigan. Some cat must have stepped on it's wittle tail:)  

[red hill]

Hope all the mice keep squeekin' cause I'm learnin'!

[canopyboy]

TTT for those of us who think to hard about things sometimes and confuse ourselves....