lets talk positive vs negative tiller

[Roy from Pa]

Bull crap on center shot to shoot good, all ya gotta know is how to tune arrows to your bow. Now ya whizzed me off so I hain't gonna make ya a bow.

Give me time ole boy, give me time:)

[Bowjunkie]

Make sure you tiller it right  

[Art B]

If you're asking if drawing dead center of both the bow and string keeps the static and dynamic fulcrum the same, then yes. Trying to mimic the dynamics of what happens in the hand to the tillering tree/board isn't going to happen with this design. Not to say you can't tiller out a bow for this design on a tree but you have to be remindful of tiller requirements as you proceed.

"Art, I'm not sure we're saying the same thing. What I'm saying is that the grip doesn't change the underlying physics. And if anything, getting the heel of your hand into the grip will lower the center of pressure on the bow, increasing the push/pull line's angle relative to string perpendicular and necessitating an even stronger lower limb for the same string grip"

Yep, same thing Dave. Take for example you use an elevated rest and the hold on the string raises also. What happens? More heel of the hand is required and a stronger lower limb to maintain balance. Shooting upright vs canting, same requirements. Do you disagree with that?  .....Art B

[Echatham]

geeez roy, just ribbing ya about the centershot, you ought to know ya done schooled me right on that.  so... Im sorry i said that... can you still make the bow?  

[Roy from Pa]

NO.

[Echatham]

so pulling from a higher point on the string does what to the dynamic fulcrum? moves it down?  let me put that another way... pulling from a higher point on the string puts a heavier boy on the lower limb?... which makes the dynamic fulcrum lower?  meaning that the higher up the string you are pulling from, the stiffer you need the lower limb?  assume im gripping from geographic center of the bow.  i don't know if i am building same length limbs on my next bow or not.. but i really want to understand this before i do anything.

[Roy from Pa]

   

[Echatham]

Originally posted by Roy from Pa:
NO.

[John Scifres]

Jim Fetrow used to recommend weighing each limbs draw weight separately.  Thoughts?

[Roy from Pa]

Perfect tiller, 1/8th negative, low wrist grip.

 

Even better perfect tiller 1/8th positive higher grip, and sweet form:)

 

So it all depends on the archer and how they grip the bow as to how you tiller them. But limb sync is everything:)

[Echatham]

Originally posted by Roy from Pa:

So it all depends on the archer and how they grip the bow as to how you tiller them. But limb sync is everything:)

so how did you determine the amount of positive/negative tiller to be optimum for each of you? and what method do you use to ensure limb sync?

guys i really do apologize if my questions are dumb.  I feel like you guys are talking about calculus and im bugging you about multiplication tables. I just really really want to understand!    

[Zradix]

Hey Roy..

On that one in the pic you did the "follow the line" trick on the tiller tree.

Would you say that's the ticket?
Thanks  

[Art B]

Echatham, heavier boy, yes.

Your ticket for the sweetest shooting bow, IMHO,  would be where the static/dynamic fulcrum is the closest to center. That would be a straight wrist/low contact design like Dean and Jeff makes. Upper limb appears longer (it's not really, handle is lower to accept grip) Tiller/search for even limb strain as you shoot your bow in. After a couple of bows of this type tiller requirement will reveal itself.

That's all I got to say on this subject......Art B

[Echatham]

Thanks Art.  would any one care to talk about timing/sync?

[Roy from Pa]

NO.

My head hurts enough now.

I'm going to the bow shop and make a bow.

Might even put wheels on it, then I kin adjust the wheels for equal timing:)    

Your nutten but trouble, Eric...

   

[canopyboy]

Originally posted by Art B:
Yep, same thing Dave. Take for example you use an elevated rest and the hold on the string raises also. What happens? More heel of the hand is required and a stronger lower limb to maintain balance. Shooting upright vs canting, same requirements. Do you disagree with that?  .....Art B

Not sure, we might be saying the same thing, but not sure for the same reasons.  Then again, I've never been that good at explaining myself, so maybe.

What I'm saying is that as this virtual push/pull line between the center of your bowhand pressure and center of your string hand pressure takes a larger angle to the arrow, you need a stronger lower limb.  If the angle is zero and you are pushing and pulling in the middle of the bow and the middle of the string, both limbs should be balanced.  If the angle is zero (parallel to arrow) and you are pushing pulling above the center of the bow, you will need a stronger top limb per Dean.  But if this line starts to angle down from the arrow, you will need more and more of a stronger lower limb.


So, I agree that elevated rest does the same thing as low grip by increasing the angle of the push/pull line relative to arrow.  Do not agree that an elevated rest means you need more heel (in fact I think less would be better.)  Do agree that more heel AND an elevated rest lowers the center of pressure on the bow while rasing the center of pressure on the string and increases this angle even more.  So therefore I do agree that an elevated rest will need a stronger lower limb for the same grip.  Do not agree that canting the bow versus straight up and down will change the limb dynamics unless the shooter changes his/her grip as a result (although this is often the case.)

[TimBoA]

Here is the problem (I think):
"What does Dean do that causes Static and dynamic fulcrums to diverge?"

"Only way you can get that much divergence (2") is by gripping this design inappropriate and tillering from there. That's trying to fit a square peg into a round hole again."

 and...

"First thing you need to learn is how to grip the bow"

I also like to shoot with my palm and heel off to the arrow side, and use my thumb for a fulcrum, when shooting my Torges-style selfbow.  It shoots the best that way, and I don't have to worry about bending my bow elbow.  I don't care for the suitcase style, heel down grip.  That doesn't mean it's incorrect (although it might be for a Hill-style straight grip).

[canopyboy]

Will also mention again that I'm a relative newcomer to the bowyer thing, and my few years are nothing compared to a lot of y'all's....

I'm just working on it from a fundamental physics perspective as an engineer that can't let things like this rest until they make sense to me.  Not saying I know what I'm talking about there either though....

This has been a great thread and I've really enjoyed working through this.  Hopefully some of what I said made sense.  If not, hopefully it didn't bore or irritate too badly.

[Art B]

When we talk about dynamic function we often  ignore the balancing the limb's masses. So to use less hand pressure on an elevate rest, would, imo, ignore the latter. But that's just my opinion.

You're right of course, I do modify my grip somewhat when shooting this type bow. But that's more of a natural response rather than a planned event for me.......Art B

[Echatham]

didn't realize it but this thread has been done before here:  http://tradgang.com/noncgi/ultimatebb.php?ubb=get_topic;f=125;t=006299;p=1

i found some more nuggets in there that helped clear it up for me.  its making some sense now.  I really needed the physic's teacher explanation on the force and leverage applied to the limbs.