New string and sight marks.

dvd8n

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I tried out the new string that I made tonight and discovered that my sight marks had changed. Shooting 20yds I was using my 25yd mark.

The string was made of the same material with the same specification.

The only changes were that it is slightly longer to get some extra twists in it (the last was a little short and hardly twisted at all) and the centre serving is longer to get the end out of my eye line.

The nock point is in the same place and bare shaft was fine.

I can understand a slight change in sight marks due to the changes but 5yds seems a lot.

Any ideas?
 


geoffretired

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Being longer and with more serving it will be a little heavier.I know that on compound strings they fit weights to get more speed. I think the idea is that the slight extra weight means the string accelerates more slowly initially but carries more speed later.
Other reasons could be thenocking pont is a little lower.
Just out of curiosity, you made the centre serving longer to get the end out of your eyeline. Does that mean you can see the serving?
I thought the serving was supposed to end no higher than the nose.Or is that just Olympic recurve.
 


dvd8n

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For barebow the end of the serving is not meant to be visible. When I exclusively gap shot I had it finishing just above my finger but I have been experimenting with string walking recently so I extended it to my eyebrows to stay legal. But last night I was gapping.

I did realise that there would be more weight in the string but I was expecting a drop of an inch or two, not a foot.
 


dvd8n

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I wondered about the nocking point - would a lower point not send the arrow higher?
 


geoffretired

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Thanks for clarifying the serving issue. I can see the sense in not being able to see where the serving ends. I have not got a full understanding of barebow rules and wondered how different they are from sighted shooting.
Heehee ,I misread your sight mark comments. So the bow is slower with heavier string. I can understand that, despite saying that it could produce a faster launch. I feel it is more complex than simple string mass. It does work on some bows. I guess there are other onditions that have to be met before there is a speed increase.
The nocking point aspect might have a bearing on the results. More serving may change the way the arrow is launched. Perhaps it needs a different nock height to get the same launch .
I get very interested in all things connected to tiller and
I can imagine that a change in weight and its ditribution on the string could change how the limbs react during the power stroke. If
I was still wanting to shoot high scores, I would fit a nock set (brass one) at some point above the serving and see what happens. Then fit one below and note any changes. Finally remove the top one leaving the lower one to see what t hat produces.
 


geoffretired

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I would say that the chrono will show a change of speed...which could be the reason.Perhaps a bareshaft test would show a change in flight characteristics.... another reason, possibly. It might be a different nock fit on the new string. It might be a combination of some or all of the things mentioned so far. Or something else entirely.
 


dvd8n

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I did shoot a bare shaft and it grouped nicely with the others and was straight in the boss.

I'm thinking that I should revisit nock fit but my wife has ideas about how I can better spend the rest of the weekend :)
 


KidCurry

Well-known member
I would put my money on nocking point position. You could try lowering your nocking point until you get the old sight mark back and note the change. I'm betting it's tiny :) Everything else on a recurve is very predictable. At 20/25yds I really don't see things like nock fit are going to have any affect.

Your string is longer so heavier, probably more wax?... if you have a grain scale you could weigh them. But even so I would still go with nock point :)
 


geoffretired

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Better ideas or just other ideas???
I have heard people saying that top archers( or better archers) have two strings, both shot in so they canchange them quickly should one have a problem. I wonder if they make two at the same time, so they get them as near identical as possible.That would make sense for several reasons. I also wonder if they get the same sight marks from both strings, without having to adjust in some way.
 


caspian

New member
the more advanced recurve archers I make strings for them order them in matched pairs. they are made one after the other on the jig without moving adjustments, same climatic conditions, same tension, same timing. and I set serving position and length to +/- 1mm and control the centre serving diameter with digitial verniers to get them as closely matched as I can.

I don't doubt there is some minor variation, but it's as little as I can feasibly make it for them.
 


dvd8n

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Better ideas or just other ideas???
Ideas different from mine ;)

But I managed to slip away to the practice butt at the field course this morning for an hour. I served up the second string that I made at the same time identically but with a slightly looser nock fit - and (drum roll) - my sight marks were back where they were with the original string.

I'd swear that the nock fit on the first one was fine but I guess the arrow was hanging up on release enough to mess up the sight marks.

Either that or something else is different of course. At some point I'll re-serve the first string with a looser fit to confirm.....
 


geoffretired

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In a former life, when archery was a bit of a novelty for me, I used to test each nock fit by pulling it slowly off the string with a ruler close to the string so I could measure the deflection each time. I suppose the same could be done using your two strings to see if they both give the same deflection.
 


geoffretired

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Heehee.
It would make a fascinating study to find out how many puzzles, like this one, have solved by the most unlikely suggestion.
I guess we can all come up with a list of possibles, but sometimes the answer is further outside our control because we don't have a clear picture of what hasn't been checked. Or has been checked but in a different way from the one we expected.
I'm still scratching the back of my head, too. Not all treatments for head lice, work.
 


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