latest GUAVA, ........a short Cotton backed flatbow (Pics & full draw )

[DCM]

Manny,

I cannot say it more plainly than this.

"As I understand it MORE tiller would be required for the so called sym design (ie. arrow pass 2", or half the handle lenght, above center)."

But restating, no, sym limbs need positive tiller, as I understand it.

Actually there's a nuiance to thsi question perhaps other's can speak to.  Positive tiller is used to offset the imbalance of having the arrow pass (nock point is really the important aspect but for simplicities sake lets stick to the the dimenions on the bow itself) necessarily above the fulcrum.  But if the arrow pass is at dimensional center, versus the fulcrum, does this tend to mitigate the need for tiller, or have no effect at all, because the arrow pass is still above the fulcrum?

I know based upon my experience that the so called asym (arrow pass at center) bow does need positive tiller.  In my experience less positive, but it's really such a small difference, like a 1/16" to an 1/8" or so, it's hard for me to conclude anything from it.  Particularly since my bows rarely take over 3/16" of tiller.  But I tend to draw with my middle finger, more like a 2 under, and high wrist the bow.

Sorry to sidetrack your thread Manny.  But like you said earlier, there's just so many cheerleading threads a man needs to read in a lifetime, and having a little meat an potatoes throwed in can't really be counted as being all that bad in my view.

[NOMADIC PIRATE]

LOL Mimms after 4 of your posts I still don't understand what you're saying

let me tell you something,..and this is a fact, I will never get to the level of some of you bowyers, because by nature I can't get interested ( or better, don't understand it ) in the tecnical side of the craft, ...when you say "string angle" that's allready chinese for me ....most of the terms you used in your posts totally whent over my head

On PALEOPLANET quite often there's tecnical threads, I open them because I want to learn, but I quickly realise after a few post that I don't understand a word they say ,..needless to say, I don't open those theads after that


I'm more like,

it feels good...., it looks allrigth...., it shoots where I aim......., DONE !!! 

BTW no sidetracking, I rather listen to the truth than any sugarcoating

[DCM]

I think you are jsut playing possum, which indicates an already evident degree of high intelligence and wisdom.  ;-)

But if you do want to pursue some of these concepts, expressions, like string angle, I'd be happy to participate.  String angle is simply the angle the string makes with the limb at full draw which necessarily relates directly to how the string acts upon the arrow on the loose.  Generally the smaller the angle the better as it gives more mechanical advantage, like a lever.  All else being equal, a limb with small string angle will outshoot one with a large string angle.  When there is a large disparity between the upper and lower string angles, in my view whichever one sports the better string angle, generally the lower, is getting a free ride at the expense of the other.  That's my whole point about having the arrow pass at dimensional center.  It makes the string angles the same on both limbs.

[NOMADIC PIRATE]

O.K., O.K., I'm getting there, but do you think that you'll get an even string angle when you actually draw the bow by hand ?

the arrow pass is still not at centre, and furthermore the string is drawn even further up that the arrow pass.

I'm not asking this to be a smart ass, I'm really trying to understand this, I never payed attention to it.

BTW,...did I mention I hate full draws from the tree ?

[DCM]

Yes, the objective is to get an even, or more appropriately a MORE even angle.  Remember everything is shades of grey here.  You can adjust the geometry, the tiller, the nock point all to fit together, within reason, with lots of variation of each.  I tend towards wanting both limbs to be as equal as possible on the return stroke, like a team of horses pulling together.  I don't want one horse standing off to the side while the other is more dead ahead of the load.  Seems like to me it makes everything more effecient having them pull together more similarly, along the same path, that is as near dead ahead of the load as possible.

I admit it is very subtle, but I can tell the difference between these two bows.  One has the arrow pass at dimensional center, the other 1 1/2" or thereabouts above.  Both 58" bows drawn to 28".  Once you've had a chance to guess which is which I'll post the difference in string segments. 

[NOMADIC PIRATE]

I remember those bows

The symmetrical one is the one on the rigth, It looks to me that it has a more shallw string angle on the bottom

[Rich Saffold]

Ya the one on the right looks better

[Dano]

Looks to me like the bow on the left is at dementional center and the bow on the right is 1 1/2" above center, what do I win?? I prefer cupie dolls by the way.    Oh yeah and the bow on the right looks like a better shooter.

[DCM]

Well you can lead a herd of horses' arse to water....  LOL

The one on the right is the "sym" bow.  The limb segments are 92:98, the left is more centered, 92:95.  These are millimeters measured directly off my monitor.  Just goes to show you how small of an asymetry one's eye can detect.

The one on the right has a smoother draw, sports a better string angle throughout because it's bending more in the center, stiffer on the outer limbs.

Timo prefers the bow on the left.  I don't care particularly for either, both being too short and heavy for my taste.

Sorry it to so long to get back to the thread.  Actual life got in the way.

[Pat B]

Manny, Your bow building philosophy mirrors mine.    I don't get a lot of the technical stuff either and to me it doesn't matter why, just that it does!     I know its all important and without it wood bows wouldn't be what they are today but I will leave it to the guys that get it and gleam and absorb what I can.
   I prefer a symmetrical lay out because it is easier for me to see good tiller. For years I went with the
"1 1/4" above and 2 3/4" below center line" layout but today I lay it out equal.     Pat

[Ryan_Gill_HuntPrimitive]

Looks really great Manny, that guava has some really nice looking grain and character to it. its on my "wood to do"  list. the back looks excellent, great detail - Ryan