Arrow clearance problem?

[h20vrrq]

Well, my new bow has been great to shoot, and over the last couple of weeks I ventured down to the range and tried shooting at 50-80yds. All was going well, scores not too bad and groups quite good (when practicing I shoot for groups not scores).

Anyway, the back of the arrows were all over the place in flight, and a club member asked how close I was to centreshot and when I checked (bow hasnt really been tuned) I found that nearly all of the arrow could be seen to the right of the string. OK, so I adjusted the arrow rest to the left until arrow was hidden behind the string when I lined the string up in the grooves of the cam. Put the sight in line with the arrow as well, and shot a couple of arrows at 30m. The impact of the arrow was a good 30cm to the left of the aiming point. Tried a few more arrows and still the same result.

Got the paper testing rig out and shot some fletched arrows at point blank range. The nock end tear is about 3-4cm right of the point tear. Nock was also slightly high, but not a lot. I then tried a bare shaft and the tear was about the same length but nock height was spot on.

The arrows are ACC 3L-18 being shot from a Martin Cougar III set to about 50lb. According to the Easton arrow calculator they are just about ok for the bow, but a higher poundage would need a change.

A a test I wound the poundage up to 60lb and did more paper testing. Exactly the same tear pattern with fletched and bare shaft. Wound the bow down to 46-47lb and still exactly the same tear pattern.

The arrow rest is a Golden Key premier which is 16 years old and still set for my old bow. Spring is set to the lightest setting I can to support the arrow.

Am I missing something obvious or does this sound like an arrow clearance problem?

[geoffretired]

Setting centre shot has been discussed on the forum recently. See if you can find the thread. I'll try to find it later, too.My initial reaction is to question the use of the string lining up in the grooves of the cam. Not all cams are in line with the direction that can be called straight ahead. I would do a quick check using the string down the limbs like recurve archers do, but remember the string should not line up with the centre of the limbs. A quick guide is to find the middle of the limbs and make a pencil mark. Then make another pencil mark 3mm to the left if you are a right handed archer. Line up the string between the marks and see where the arrow is. Adjust if necessary. Another cause of left/right arrow tails is torquing the grip. Try shooting with your thumb further forward in the grip and check again. If that is worse, bring the thumb back.
Spray powder on the tails to see if there is any contact with the rest. If there is, raise the nocking point or lower the rest.
Let us know what happens.
All the best
Geoff

[MikeD]

Originally Posted by geoffretired

Spray powder on the tails to see if there is any contact with the rest. If there is, raise the nocking point or lower the rest.
Let us know what happens.
All the best
Geoff

I would just add to that if you are using the spring steel launcher (lizard tongue ??) on the golden key premier, with 3L-18s you may need to grind a bit off the points. I was getting two contact points before doing that. I have no clearance problems now with the optimum nocking point/ launcher height.

[h20vrrq]

Cheers for the info guys.

The launcher is like the one on this rest:


The groove in the cam is 2.5mm away from the centre of the limb.

I've just checked my arrows and the right side fletch has faint marks on the underside, this suggests its has been contacting the rest, but this may have been done before I set centreshot.

[geoffretired]

If the wire at the end of the launcher makes a wide "V" shape, the arrow will sit low into it and could be adding to the problem. Altering the nocking point or height of the rest will throw the tail up slightly and should clear. Fletchings with marks on usually means the arrow is still pressing onto the launcher as the fletchings go past.
I would check for contact first. Correct that if needs be.
Adjust centre shot in small steps to try to reduce the tears. ( accept half inch vertical if necessary)
If there is no contact and the adjustments can't reduce the tears to less than one inch, I would look at torque issues. Change hand position to see if that helps or makes it worse. If it gets worse try the opposite direction next time.

[pwiles1968]

There are several posts that discuss center shot, here is one http://www.archery-interchange.com/f...ghlight=center

I treat center as not having to change windage while changing distances.

I assume you are looking at your arrow flight on a perfectly calm day.

[Christopher Lee]

Here's something I always do when setting up rests, regardless of the type of launcher used ... lizard tounges, carbon arms, 2-prongs etc. This referes to conventional rests and not drop-aways.

Basically, after setting up for level and finding my practical centreshot using the walk-back technique, I experiment with the spring tension of the rest.

What I do is set the tension so low that when I nock my arrow, the launcher tips all the way down, or almost all the way down.

As I draw back, the remaining front of the arrow moves up (less pivotal weight on the launcher by the time the arrow is being drawn back) and is fully supported the last 2-4 inches before I reach full draw.

This give me the psuedo effect (and advantage) of a drop-away rest without all the extras parts and possible disasters that could happen at the worst possible moments during a tournament.

So far, with such a set-up, I've found that clearance is not so critical* even with extreme off-sets or even a helical as the spring tension is set so low as to cause minimal disturbance. I can have the fletch contact the launcher with little detriment as the launcher get easily pushed out of the way.

You'll have to experiment and find out what tension and nock orientation works best for your set-up if you want to try this.

Sounds radical? But a bow with pulleys and wheels and all sorts of extra string is extremely radical to begin with.

Think DIFFERENT.

CHEERS!

* So far I've used this set-up with all sorts of harder fletches up to 3 inches, including the extremely hard X-Wings spin-type vanes and 3 inch feathers with helical.

[h20vrrq]

I assume you are looking at your arrow flight on a perfectly calm day.

Yup, correct, no wind and back of the arrow was dancing all the way to the target.

If the wire at the end of the launcher makes a wide "V" shape, the arrow will sit low into it and could be adding to the problem.

I have already narrowed the "V" so the arrow sits quite high.


Right, I've been fiddling with the set up tonight and made a bit of progress (I think).

After measuring true centre and then moving launcher until it was 2.5-3mm left of centre I found it was almost in exactly the same place as my previous centre shot calculation. So I left things as they were.

Next reduced the launcher spring pressure so when nocking arrow it lowered the rest but at full draw the rest returned to correct height. I also raised the nocking point by 1/8 inch. Shot a few arrows like this and the results were much better, as arrows were only a 10-15cm to the left of aiming point.

Good start, I then worked on hand position on bow and moved it more to the left, shot more arrows and now even better, maybe 5cm left of aiming point.

Tried bare shaft shot and it hit just left of main group, but only just left (2cm) but at the same level.

Time for a bit of walk back tuning I thought. Went from 10-20 yards and arrows all in nice group (just left of aiming point) with not a lot of difference in vertical line.

Back to 30m and shot more arrows. This time they were back to 10cm left of aiming point. OK, look at arrow rest position and moved it right in small steps and realligned my sight to be in line with the arrow. No matter where I put the rest, the arrows always impact left of aiming point by about 10cm or so (but group very good).

I'm fairly sure nocking point is right, I've double checked centre shot, and with everthing all in a nice line, the arrows are still impacting left of aiming point. I'm now very confused.

Is it worth ignoring centreshot and just do paper testing until I get a decent tear?

I'm also thinking about moving to a drop-away rest. Anyone recommend one with good vertical/horizontal adjustment?

[Christopher Lee]

The idea of centreshot and paper tuning are only starting points, and a guide.

From what you've described, it doesn;t sound like changing rests would solve your problem, and neither does it sound like clearance is a problem.

If you're getting good, tight groups, and your hand positioning and form are very consistent, I would try moving the rest a little more to the right and do a few more walk-backs and adjust accordingly.

Also, eventhough the charts say it's just within the spine range for your set-up, try stiffening the arrow by lowering the point weight and see what happens. I've found that very often, when shooting medium to hard cams, going a little stiffer rather than being spot-on or weak seems to solve a lot of tuning problems.

Hope this helps.

[geoffretired]

It sounds like you have done all the things to reduce errors from contacts with the bow. The walk back seems to be bringing some better results;certainly the groups seem pleasing. You say you are now confused. You are not alone, I certainly have had confusing results in the past;there are so many variables it seems. One thing I think I noticed from your post is that you set the sight to the arrow alignment. If you set the sight to get the first arrows hitting the mark, you might find that gives a good vertical line down the boss. In a perfect world, the arrow would fly in the straight ahead direction, the way it is pointing, and the sight would be just above. Sometimes the arrow flies along a line that is pointing slightly to one side of straight ahead, so the sight needs to be off set a little to counteract that. When you do walk back, do you shoot one arrow at each distance or a group at each distance?