limb timing/sync question

[Echatham]

so im playing around a bit with some advice from bowjunkie, set my tree up to allow the bow to pivot on the cradle.  i understand it will tip towards the limb thats too strong.  so what does it mean if the bow immediately tips toward the upper, then slowly creeps toward the lower through the draw?

[John Scifres]

Drastic differences in limb strength can be seen at brace.  That's my first indicator.  Watching it through the draw on the tree is a great test.  If it is jerking around, something is off.  I bet the top limb is still too strong.  Draw it by hand and feel the balance.  Close your eyes.  Be the bow.  Be the bow.  Be the bow.

[Echatham]

i think maybe cause im pulling the string from above where im gripping, thats why its tipping to the top at the first inch or two of draw, but the lower limb is actually stiffer causing it to gradually rock towards lower limb during the draw. sound right?

[Echatham]

i can't really feel any rocking drawing by hand, even if i just hold the grip by the ball of my thumb... a single point hold

[John Scifres]

Are you placing it in the tree and pulling it from the same places by hand?  Mark it to be sure.

[Echatham]

yes and i did mark it. pencil on the handle and tape on the string.  its a radiused handle and a radiused cradle.... and it doesnt quite balance right on it. wants to tip toward upper limb at rest. then when i start drawing it tips more.... then straightens out as i get to about 20".  am i making sense or do i need to make a video?

[Echatham]

the lower limb looks a tad stiffer at brace.... what they call 3/16" positive tiller.   maybe i will try the other method.... using a cradle that keeps the bow stationary and just making sure the pull point on the string travels straight down.  do you think that is more or less accurate?

[Art B]

Well, you grip a bow for how it was designed, and you design a bow for how you intend to grip it. Did you do that? If your upper limb is longer, then that would indicate a medium to straight grip and would require less positive tiller. Right now with that 3/16" positive tiller, and without knowing how you intend to grip your bow, or limb layout, it would be hard to give any advice.

I think the best thing you can do at this point is get your bow in the hand and find yourself a mirror.......Art B

[Echatham]

i will post a pic when i get a chance. i know how i grip it but i dont know how to describe it.

[Echatham]

 

[Roy from Pa]

Just set it for a 1/8th positive tiller on the tree, then shoot it and see how it feels to your bow hand. If either limb tip seems to move towards you more than the other, then take some wood off the limb that is tipping towards you. You can replicate your bow hand on the tree all you want, but the bow hand knows the truth when you shoot the bow... That's my story and I'm sticking to it!

Eric, don't put too much thought into this tillering process, tiller the bow so it looks decent at brace height, then go from there. 20 guys will give you 20 different answers when it comes to tillering.. Some of them are full O chit, some of them think they know their chit, and some of them don't know chit. I fall into the latter:) But my bows look nice and shoot well...  LOL

[Echatham]

Roy i like how easy that sounds!    you know how i like to over complicate things.

[Roy from Pa]

Ya I do:)

[Bowjunkie]

Eric, your tree is revealing things to you as I'd mentioned. You just need to know how to interpret the message. What you saw as the bow leaned one way right away but then began to straighten/balance itself was 'normal'.

When you first put a tiny bit of pressure on the string, you are doing so from above the bow's center... (the center you would find equadistant from the tips). This causes the bow to begin tipping right off the get-go, and then as the relative strength of the limbs comes into play, the balance point shifts from the static to dynamic. It is the dynamic balance at full draw we seek.

This transition takes place under the bow hand and varies in dergree dependent on design, grip, and relative limb strength.

This static to dynamic transition is much more harsh on symmetrical bows where the string is pulled from even farther above the static center. Non-symmetrical bows, as you're working on, have a smaller, more gentle shift to accomplish and do it earlier in the draw.

Do NOT tiller to a predetermined tiller measurement like Roy said. You are on the right track and I have high hopes for you and your bows  

My advice is to tiller it out seeking balance, either by way of the piviting cradle, or if it freaks you out too much, switch to the stationary cradle and use the perpendicular fulcrum travel to balance it. Then go back to the piviting cradle to see how ya did.

If your tree is set up right and you tiller for limb harmony, that sucker will feel perfect in your hands the very first time you draw it... tiller measurements be danged... I promise.

[Roy from Pa]

Ah bull crap junkie:)

[Echatham]

so Jeff, the condition i described above, where it creeps toward the lower limb during the draw, that DOES indicate lower limb is stiff right?  regardless of what happens during the shift from static to dynamic fulcrums?

[Roy from Pa]

That is correct, Eric.

[Echatham]

ok thanks Roy!

[Echatham]

i now feel confident enough to touch the scraper again      I want to be as judicious as possible in my scraping because i don't have much margin for error and i don't want to be chasing tiller back and forth and losing weight the whole time.  right now its pulling 30#@20, and 32.5#@ 21.  im thinking if i do everything right i can safely be in the low 40s at 28.5" by the time its shot in and i can hunt with it. Tiller first, I won't sacrifice tiller for weight, i don't need reminding.  Thanks a million guys.

[Bowjunkie]

Eric, in regard to your last question, are you using the piviting or stationary cradle?

Actually guys, I would tiller and time the limbs by the stationary cradle most of the way so that the static balance and shift didn't deceive me, because until the dynamic balance overcomes the static, we could be led to believe the bottom limb is too strong when it WON'T be at full draw. But Eric, you may already be past that point.

The piviting cradle may be better to use toward the end to verify or 'fine tune' the limb timing. IMO anyway. At least until you're a little more familiar with it.