Nock travel

[DC]

Couldn't think what else to call this. After reading many comments about the arrow rising and falling when you're drawing it I'm finally seeing it. This bow wanted the nock to be very high. I was making a new string for it and while I was serving it and had it in the vise I drew it and saw the arrow rock up. So I set up some paper and took pictures. The first is with the arrow just sitting there. You can see the arrow is parallel with the black line. Next picture is with the arrow drawn about 5-6". You can see it ain't coming back straight. This bow has 3/8" positive tiller. Measured from the center of the grip the bottom limb is 32" and the top is 32.5". If I consciously lift on the string when I draw it I can make the arrow come back straight but it's actually quite an effort. So the bottom limb is too strong. I would rather not lose any weight by scraping the bottom limb. Do you think shortening the top by 1/2" would solve this. I'm thinking this might explain why I can't shoot well with this bow? Well, I can't shoot well with any bow but this one's worse

[willie]

very interesting observation and inquiry. Could this be related to the timing debate that you hoped to avoid in the other thread?

[DC]

Yes but maybe I'll understand a little better with this under my belt .

 I did some more fiddling. I tried nocking the arrow about 1/2" higher and it made the problem worse. So I nocked it about 3/4" below center and now the arrow stays parallel with the line. I'm going to go out and shoot it. See what happens

[Ed Brooks]

have you tried this with another bow, say one that shoots good for you? Ed

[DC]

I just gave away my daily shooter so that's out. I'm not really a good enough shot to get any definitive data that way. I'm just finishing a new bow and will do some comparisons. I'm just hoping that someone that understands this will chine in.

[Dances with squirrels]

This is exactly why I tiller bows the way I do. I have my tillering tree set up so that it reveals this very early in the draw, and I make adjustments then.

You're seeing the discrepancy between the relative strength of the limbs. The stronger limb will flex less than the weaker one, so then travels less distance... traveling less distance makes the arrow nock move in the direction of the stronger limb (relative to the handle) during the draw. And conversely, move back toward the weaker limb upon release... which can inflict the arrow with porpoise and make tuning a real pain in the butt.

Tillering trees (rope and pulley system) can easily be set up to reveal this throughout the tillering process.

[Lumberman]

So the proper fix is move the nock or take a little more off the strong side?

[Dances with squirrels]

Yes, shortening the weaker limb will help. But I design my bows with certain limb lengths so they balance in the bow hand, so I would be more prone to weakening the stronger limb to achieve dynamic balance even if it meant a lighter draw weight. Your call though.

As you judge, be sure to hold it and draw it the way you will while shooting. Otherwise, how do you know you're doing the right thing, or when to stop.

[bow101]

Good pint about the arrow not staying parallel and good description with your photos.  I shoot the bow and tinker with the arrow shelf and nock height after, this seems to fine tune the bow to a point of satisfaction.  Hopefully you will come up with a fix for your dilemma.

I was shooting my first Takedown the other day its only 34# the arrows are spined at roughly 40# and over.  Yes my shooting has improved in the last 6 months but why was my grouping so good @ 60'  it literally blew me away.   My shooting really was that good. 6-8" grouping. 

[Red Tailed Hawk]

Makes good sense dances with squirrels. Thanks

[DC]

I turned the bow upside down, and using the leather grip as an arrow pass I marked the string at 90 degrees to it. Then I went through it again. It didn't change that much. I'll have to play more.
A question though. If I tune my bow so that the arrow draws straight when the bottom of the arrow is on the 90 degree mark would I still nock it a bit higher when shooting? My idea being that it would lift the arrow off the pass a bit. Kind of a vertical paradox.

[Dances with squirrels]

Lumber man, I prefer to set all of my nock points at 3/8" above perpendicular to the shelf. Measured to the bottom of the nock point, this puts the arrow nock 1/8" higher than the point at full draw Then the limbs are balanced in strength so the nock point comes straight down the tillering tree, being neither pulled left or right. Bingo, balance. When the new string is made, the nock point is set right at 3/8" and it's good to go. The bow is inherently tuned... no moving the nock point up or down trying to find balance after the bow is done. Besides, how do you shoot if, in order to achieve that balance, the nock point has to be below the shelf?

Yes, the nock is pulled toward the stronger limb during the draw, and I weaken it until it doesn't.

[bow101]

I turned the bow upside down, and using the leather grip as an arrow pass I marked the string at 90 degrees to it. Then I went through it again. It didn't change that much. I'll have to play more.

Maybe its more of a handle problem, are the arrows smacking one area of the handle to hard.  Could cause deflection. that has been one of my problems.

[George Tsoukalas]

I don't pay attention to pos. vs. negative tiller at brace. I like the bottom limb to be very slightly stiffer than the top by perhaps a 1/4" or less at full draw.

However, sometimes I'll measure both limbs in 6" increments and look to get no more than a 1/4" difference in brace measurements between xcorresponding area on both limbs.
.
Have someone snap a digi. I assume you've reached full draw?

As you draw, even at low draw lengths, try to sense the limb pressure at the handle. It should be even. Try to sense if the limbs are tipping.

Your nock point should be above center.

Jawge

[George Tsoukalas]

Almost forgot. You can also move the arrow pass toward the weaker limb.
Tillering to even the limbs up a bit more is also an option.
Jawge