View Full Version : nock centerline

09-05-2008, 09:36 PM
Purchased QAD Ultra-Rest HD Pro and installed with original nock point and release arm would not lay flat when down, it would smack the arrow shelf hard and point up at about 5-10degree, so I readjusted so it would lay flat. No smacking! The nock point left arrow pointing up radically, so I moved nock up about 1/2", so arrow was straight, now nock centerline is almost 1" higher than string centerline, it was about 1/2" high before. Test shots reveal little, shooting 10' inside apt. My question is will I have to go back to WhiskerBiscut or will my rig be fine after some further micro-tuning?
From what I measure the arrow shlfe is the string centerline, so nock would be high anyway. Just how high, is ok?
It shot fine, so I'm more concerned about math than flying arrows:cool:

09-06-2008, 07:05 AM
I think what you are asking is how to set your nock point?

First, your arrow rest should be set so your arrow travels thru the center of the bow - arrow should travel thru the centerline of the rest bolt holes in the riser.
Using a bow square, the bottom of your nock should be about 1/8" above where the arrow lays on the arrow rest.

Now set your center shot using a centershot guage -

09-06-2008, 11:41 AM
The problem is the QAD rest, the only way to set it w/o it smacking the shelf is to move nock up so that arrow lines up about 1/8" higher than the hole centerline. Again, it shots fine but just wondering?
Look at top pic you can just see bottom of holes. 2nd shows launcher arm as low as I can get it w/o smacking shelf. I muscled the nock up to line up arrow.

09-06-2008, 03:07 PM
I would keep my arrow going thru the center where it should.
Maybe you could pad the shelf to eliminate the noise?

many time you can move your d-loop not by musceling it, but by rotating it up or down the serving. Your serving is like all thread rod.
Before d-loops we used tied on nocks, they easily screwed up or down for adjustments.

09-06-2008, 05:02 PM
Try this again. Let's get this "center of the bow" things straightened out.

The rest on your bow should be positioned so that the arrow aligns approximately at the same level as the rest mounting holes, just like in the one picture.

As can be plainly seen with the use of a tape this is not half way between the axles. It doesn't take a rocket scientitst to figure out that you can't align the arrow perpendicular to the string in the physical center of the bow because the arrow would have to be shot through the arrow shelf. Obviously this isn't going to happen.

In short, when properly mounted a rest will hold the arrow above the physical center of the bow because that's where it's supposed to be mounted. Then you align your nocking point so the arrow is perpendicular to the string and start your tuning process. The nocking point may have to be adjusted up or down to achieve good arrow flight (paper tune?)

But first get used to the idea that a rest has to be mounted so the arrow is closer to the top axle than the bottom. Every bow made is this way. Some more than others.

09-06-2008, 05:43 PM
My measurements indicate that the boltholes are 3/4" above the arrow shelf. ANY drop-down rest has to fall above the shelf or smack it, thus noise. Even if you pad it still hit's. Thus bounce-back, which is why I went with QAD LD tech. That and fully adjustable;) Now if they made different size, V, launcher's! And a longer mounting block:D
Like I said it still shoots fine, just wondering about what string centerline means to tuning? As the nock sits now, and the shelf is string centerline, I'm 1" above that. The arrow sits 1/8" above bottom of bolthole. Because I read about how 1/16" makes such a huge difference, makes me wonder if it'll come back to bite me later when I hope to group tighter:rolleyes:

09-06-2008, 07:23 PM
This test was shot inside apt. distance is 6yds, aimimg for center with top site pin.

09-08-2008, 10:54 AM
It's not that important that the arrow rest be positioned so the arrow passes centered on the rest mounting holes. If it's a little high (1/8") like you explained and this is what you want then so be it. You still tune the bow which accounts for the rest position. Too many guys think everything has to mount just so-so, but it';s not as important as people think.

I'll give an example. So many years ago bows were made so the deepest part of the grip was the physical center of the bow, which made the rest about 2" or a little more above center. Bows were tunable then with the same methods used today. Within reason you put things where they need to be and tune from there.

Actually, back then bows drew and balanced better than they do today. The Pearson Gen II is one bow that only a couple years ago used this geometry and was a very nice bow to shoot.

So don't get excited about the rest mounting 1/8" higher than someone says they should. These things are just generalizations. It's just like having timing marks on some cams to line up the string. Sure, it's nice when everything lines up nice like in the book, but if you need to twists a cable or string to perfect the bow's drawlength then so be it. Drawlength is more important than a cam being 1/8" out of it's recommended position.

Don't get all razzled over some things. Set the bow up the way you like it, tune it, and enjoy shooting it.

Hope this helps some.

09-09-2008, 04:18 PM
I will not lower rest cause of problems noted. Since I have sorta tuned and getting good shot placement, going now to 20yd indoor and see, will report results later, thanks guys. You'all are another reason I like this, reminds me of my ammo reloading yrs in AK.

Well it was off. They used a bubble level and then laser site and it sits even higher than before. They are not concerned about the height but the launcher hitting the shelf. I only got a couple shots before they shut down. No one ever mentioned that you could get stronger from practice, my draw weight is up to 58#'s. Anxious to see my chrono spd:)

Just shot after site adjust, 20yds