Nock Low Tuning Issue
 

Okay, this one has me stumped:

'06 BowTech Old Glory, 71 lbs., 30", QAD HD drop away w/ 29" A/C Superslim 340, 125 gr. points and Blazer fletchings, Carter release and loop.

I set the arrow up just barely nock high at rest and notice that there is a bit of porpoise to the flight at 50 yards and that everything is shooting way high so I go to the paper. There is a nock low tear that takes me about 1/2" of raising the nock point to get rid of. This is the first bow I have ever had to set a nock point this high on to get rid of a nock low tear. Anyone have ideas what's causing this? Give me the list and hopefully you guys come up with something I haven't tried. My next resort is going to be flipping the limbs around (top to bottom).

RE: Nock Low Tuning Issue
 

Way out of my league in tuning. But definately sounds like a limb or timing issue. Be curious what you find.

RE: Nock Low Tuning Issue
 

First, check your tiller. Maybe you're getting too much palm heel into your grip, so be aware of that. Make sure the cam timing is right.

RE: Nock Low Tuning Issue
 

Hey Kodiak, have you tried switching the Launcher arms on the QAD? The higher one is supposed to work better with blazers or so I was told from a tech at QAD. Would have to raise your nock point by adding this also, just a suggestion[&:]

Shane

RE: Nock Low Tuning Issue
 

I would want to eliminate the rest as a potential problem before moving to other possiblities.

RE: Nock Low Tuning Issue
 

Ahh... but what problems could it present that cause a nock low tear? There is no fletch contact (which would typically be nock high) and with the initial arrow set-up the arrow crosses level with the berger holes so it should not be too high/low. There has to be something I'm missing...

RE: Nock Low Tuning Issue
 

Just a wild, probably futile guess, but how much clearance does your arrow have under the pin guard on your sight?

RE: Nock Low Tuning Issue
 

Tiller is set at even and seems to load equally throughout the draw (balanced). Tried both high and low wrist with same result but may tinker with that some more. Binary cams don't leave any timing adjustment to be played with and the timing marks show even.

RE: Nock Low Tuning Issue
 

Now you're makin' my brain hurt.

RE: Nock Low Tuning Issue
 

Hmmm... good thought, never been an issue with that sight before so I didn't bother looking. Initial thought is that it's fine since the fletchings aren't showing marks and the guard height isn't adjustable on the Lethal Weapon 2 but I'll definitely check.

RE: Nock Low Tuning Issue
 

The rest maybe drops away too early?? We had a similar problem with one of my buddies Mathews this past spring. Just for grins, we took off the drop away and put on a Whisker Biscuit - adjusted the WB to the same position. Problem solved. Only bad thing about all this was that we never did figure out what there was about thedrop away rest that was causing the low nock tear.

RE: Nock Low Tuning Issue
 

Yeah, thanks for sharing my pain![:@]

RE: Nock Low Tuning Issue
 

I didn't see it mentioned, so I'll have to say that your arrows are underspined. In fact, I think it's quite evident. Easy enough to confirm. Just take about two turns off the limbs and see if the results are any batter.

This where I'd start. If the arrows are underspined you'll just be wasting your time and lose a lot of hair trying other things.

Barry

RE: Nock Low Tuning Issue
 

Actually nock high tear indicates weak arrow. So I'd think that nock low equals a stiff arrow. I've got some A/C Hyperspeed 2-49's in 420 deflection for my 3D rig I'll try out just to check. I've tried dropping the weight to no effect.

RE: Nock Low Tuning Issue
 

Since you've ruled out everything else, I suspect it has to be in the limbs. Tiller may show as even, but they must not be loading the same. Have you tried switching them yet? I'm sure you can bring the nock point down with a tiller adustment, but like Arthur always says, you want tiller set to where the bow balances best on your draw. It's possible that with one of the limb combinations you can have tiller close to where you like it.

By the way, porpoising in usually not a spine issue, but a nock or rest issue.

RE: Nock Low Tuning Issue
 

I would start with foot spray on the arrow to determine if you actually have clearance. Might have missed what kind of rest your using, but couldit be bouncing up and hitting the arrow? Foot spray will determine this.

After confirming good clearance, I would start with taking 2 turns out of both limbs to see if spine is the problem. If that doesn't do it then I would move towards changing tiller one at a time from each end in 1/4 turn intervals.After each change intiller make sure you adjust the nock point to level. If you can't clear it up with 1 full turn on an end, then taking it out and moving towards 1 full turn (in 1/4 turn intervals) on the other end........then move towards different arrows to see if that clears things up.

Do you have a drop away tied into your down cable?

RE: Nock Low Tuning Issue
 

-Checked to make sure there's no clearance issues; none.
-The QAD HD locks down so there's no bounceback.
-Tried a 420 spine arrow and actually got a worse nock low tear so that lead me to believe it was a spine issue so I went back to the 340 spine and dropped 8 pounds off the bow and got the same tear as at 71. So I put it back up to 68 and still no change.
-Wrist high, wrist low, palm intentionally buried into the grip, no difference.
-The rest is properly tied into the down cable.

If I get back in off the water in time tonight I'll fool with tiller adjustments to rule out a weak limb.

RE: Nock Low Tuning Issue
 

This is the first tuning problem I've had with a Binary Cam system. If one cable stretched more than another the system balances the cam timing out but wouldn't it still cause different loading of the limbs? Nevermind, I guess it wouldn't because the cables aren't tied to the limbs but thinking of it... Wow! an unbalanced set of limbs would wreak havoc with the system. Guess I'll find out this weekend and let you know.

RE: Nock Low Tuning Issue
 

Good luck Kodiak. . .hopefully it isn't a limb issue, but then again, that might solve your problems.

RE: Nock Low Tuning Issue
 

I'm curious to see if your drop away tied into that down cable is pulling on it. Try installing a spring steel type rest on it or biscuit or something that doesn't affect the cables and see what happens.

RE: Nock Low Tuning Issue
 

Good thought. I'll put the QT 3000 prong rest on and see what that does before I start tearing things down on it.

RE: Nock Low Tuning Issue
 

Here's something that might help.Try moving string loop in different places.String loop may be to high or low.

RE: Nock Low Tuning Issue
 

There may be a timing problem w/ the cams. I'm not talking about the dots and the cams being synchronized,but I'm referring to your cable stops. The Binary cams need to be cable stop timed as well. I had a similar problem w/ my 06 Tribute.
The cable stops need to conact the cables at full draw at the same time. This needs to happen justas the draw stop touches the limb. The cable stops CAN NOT push on the cables at full draw.
If your rest cord is too tight it will cause additional timing problems.

If you want to check your stop timing, a draw board is the best way. I simply use a hanging scale. First, if you are sure that all your terminal specs. are correct , place a piece of paper on both your cables where the stops will contact them at full draw. BTW, dissconnect your rest cord.
At full draw the paper ( 1 X 5 piece of paper)will be between the cable and the stop. You should be able to pull the paperbetween the cable and the stop w/o too much effort and not rip it. If you can't , you have too much pressure on the cable and need to twist your cables a time or two.This will move the dots, but they are for reference according to Bowtech. There is no EXACT position for them. My dots on the outside of the limbs are-1 full dot, and the limb cuts the second one , with one fulldot on the inside of the limb. The goal here is to not have the stops pushing hard into the cables.

Now, connect your rest cord and check the timing. It will change the timing and letoff.

I have attached a qoute below for your information.

"These bows are very sensitive to any pressure applied to the cables. (1) When installing a fallaway on a binary cam bow it MUST be timed to rise at the last 1/2 inch of draw cycle. (2) When tying into the down cable you need to tie in 6 inches below the rest to avoid distorting the path of the cable which will cause nock travel problems (3) After you have tied into the down cable and timed the rest check the Peak draw weight and holding weight of the bow. I think when you do the math you will find the letoff percentage is about 65%. When you then spread the cam timing where the top cam is retarded 2 twists compared to the bottom cam 80% letoff will return. This timing can be done in one of three ways. If you would like to slightly lengthen your draw add 2 twists to the cable to the top cam, if you would like to slightly shorten it remove 2 twists from the cable to the bottom cam and if you are happy with your draw length add 1 twist to the cable to the top cam and remove 1 twist from the cable to the bottom cam. That's about it. The folks at Trophy Taker have set up some of their rests on Allegiances and found the same thing to be true as has **** ******. In fact it was Mike who first suggested the idea to me. He was and is right."

Of course this may or may not be a contributing factor to the nock high situation, but it fixed mine. I hpoe this helps.

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RE: Nock Low Tuning Issue
 

Well I finally got freed up from killing fish long enough to work on this bow. Here's what I found out:

The nock low issue was from the rest pulling on the down cable. (I'm still having trouble comprehending it but the evidence was compelling.) I replaced the QAD with an NAP that pulls on the cable slide and the nock low issue went away but I picked up a nock right issue from rest contact that I couldn't get rid of no matter what I did. I hate to admit this but I had a WB laying around from one of the Diamonds that never sold when the shop went out of business so I put it on. BAM! Bullet hole after bullet hole. Looks like I'm a Bisquit-head now, at least as far as this BowTech is concerned...:eek:

RE: Nock Low Tuning Issue
 

The bisquit cure one of my solo cams that was giving me this smae issue UNTIL I took 1/2 turn out of the top limb.

I doubt that was your issue, but the reults were the same- the bisquit will help control an unruley arrow as it leaves the bow.

Archer58,I found the above quote very informative. As much as I love the power binaries provide they sure make tuning a solcam easy.......

RE: Nock Low Tuning Issue
 

Sheeeeesh Rob, I was getting a headache following this thread.;)

I had a similar problem with an Ultratec which inturn was a sync AND drawstop timing issue.

I had read on AT, on a couple different posts regarding how sensitive the binary system was regarding tying into the buss cable.

I was tempted to post it but since the binary's scare me, no pun intended, I chose not to.

I had a long learning curve working with the C&1/2's until I understood that the reference marks on the cams were only for "reference". Talk about old school....

I kind of miss the old days with the easy tune hatchet cams on the old HC's and Martins. Like Huffy bicycles...didn't look purty' but got ya' from point A to B.[8D]

RE: Nock Low Tuning Issue
 

I had no idea that binary cams could be so tough to tune. It seems your problem is solved for now, but you could try setting the QAD up off the cable slide too. That's how I had it set up with my first Darton Tundra. CPS sure seems easy to tune compared to all of these other systems.:D