Edge of shelf wear

[xtrema312]

I have been having issues with edge of shelf wear on one bow.  I have had this on other bows, but with nock and spine changes I have gotten it worked out.  I am not doing so well on this bow.  After wearing out the edge of my Velcro rest the last time I got it tuned with a little bit higher than I think I should have nock set.  Bare shaft was still just a little tail high in flight, but hit with the fletched shafts.  The arrows flew great, and BH's looked real good also.  

I just got the bow back after having the grip worked on, and it has new shelf material.  Now I am back to where I started. I have way high nock flight on the bare shafts.  I have gone way weak and way high on the nock set to make sure I have a good base for tuning.  So far I can’t get it tuned.

 I am shooting a curve cut to center, but built out a little with Velcro strike plate.  The bow is 54@28 drawing to just about 29”.  I also have a FF string.  I am shooting a 5575 GT at 29.5” with minimum 225 on the front.  I have tried up to 325 on the front, and I have also shot 500’s at 29” and 30.5” with 200-225.

I can get good reading on weak to stiff by changing points.  I can't get the nock high and low hits out of the bare shaft.  I have used white tape on the shelf over the Velcro to read the marks left when shooting.  I can get edge of shelf clearance, but I am almost 1" high on nock set with way high nock flight.  As soon as I come down I get shelf contact, weak shaft reading and the tail keeps high.  

I did find that I could shoot a very straight bare shafts shooting with 3/4"-7/8" high nock set and 3 under.  My shaft set-up was with 225 on the front of the GT 5575’s.  I have read that 3 under takes a higher nock set than split.  When I go back to split I am back with high nock flight, and when I drop the nock for split finger I am into the edge of the shelf and getting weak and nock high flight.  I can go way weak on the shaft, but can't get the nock point down without hitting.  

I don't understand why the 3 under works and split doesn't.  It is not tillered 3 under and shoots noticeably louder 3 under.  What is going on with the 3 under that makes it work?  If the bow was not much louder shooting 3 under I think I would just change over due to it shooting so well for me that way.

I noticed today is that I think the shelf slopes from the edge down into the riser. I don't know how much yet. I know with my arrow square on it I hit the edge when trying to swing it in or out.  I am going to try and pull the rest and see if I can tell if in fact it does slope or dish out near the riser.  I am wondering if this is my problem.  Or should this not be a big deal, and  I have a form issue?  I have seen some bows have this slightly dished shelf.  I am thinking about building up the inside of the shelf with some different width strips of electrical tape or something to flatten it out or raise it up a little to see what that does.  I could also probably use a narrower Velcro rest and take a razor blade to the edge to cut away the high side so it sets more level without a high edge.

Could this also by the carbon arrows?  How about the effects of high FOC?  When I start getting over 225 on the front I start to get over 20 % FOC.  I wonder if shooting split with a little high edge on the shelf will not allow me to get the high FOC point of the arrow up in line with the shaft flight and I am fighting more than one issue and always point low.

[JimB]

Most likely,with split fingers your top finger is putting downward pressure on your arrow.This will make it very hard to get the proper nocking point location,will cause shelf wear like you describe and will make the arrows hit the target nock high and left,as if they are weak even though they are not.When the back of the arrow hits the edge of that shelf,it kicks it outcausing the poor flight.

I had exactly the same problem and symptoms you describe and found that I held the elbow on my drawing arm too high.This caused my top finger to put downward pressure on the arrow.you can even see the bow in the arrow sometimes from that finger pressure.

Some people hold their elbow high and do just fine.I can't.Maybe my wrist is too stiff.I don't know.When I draw with my elbow closer to level with my shoulder,flight straightens right out and the shot is much quieter too.

It might be worth having someone watch you shoot.look for some thing causing downward pressure on the arrow.

[xtrema312]

Thanks JimB.  I have had some high elbow in the past, but it was not real high.  I do get some top finger pressure and this is a short bow, but I don't think it is finger pinch from what I can tell.  I did some video a while back and adjusted for the high elbow.  I will run some again to watch and see.  I know 3 under feels like it is easier to get my elbow down for some reason.  Maybe it is the change in the string angle or something. It is odd that I can shoot my other bows and I am fine.

I wonder if it has to do with how much pressure I put on each finger.

[tim roberts]

You might also try turning your knock just a little so that the outside feather clears the edge of your shelf.

[xtrema312]

I shot cock feather in and a little high so I get no contact or at least no wear on my feathers.

Well I got looking and my rest Velcro is out from my riser a little with a gap between the rest and strike plate.  I didn't think it was that much, but when I pulled it off and put it back down tight to the riser it made a big difference in the way the arrow moves across the shelf.  The bump is gone.  That little gap in combination with the gap under the strike plate and the softer edge to both Velcro pieces probably made a much large soft spot than it looked like.  The shelf looks to be flat for the most part.

I checked my LB and I am shooting that at under 1/2" nock point height with out a problem and with an almost flat bare shaft shooting in the group.  I don’t think it is all my form.  

I did some more shooting with the curve and after about 15 shots my sting went.  I had one of the two bundles break and the other stretch all the way out so it was flat to the limbs.  I don't think I released the arrow, but when that happens its kind of hard for me to recall with the shock factor.  I think it was more like the bow jumped and twisted with the string flipping out of my hand just as I put back tension into it.  I had been shooting it yesterday and noticed it was a little louder than normal.  I checked and the brace was down from just over 7 ½” to just over 7”.  I thought the string just got untwisted when the grip work was being done and I had not noticed it was not shooting as good as before.  I twisted it back up this morning when shooting it.  Now I wonder if the string along with the rest had something to do with the tuning problem.  I guess I will know when I get a new string on it and start tuning again.

[Bill Skinner]

Out side shelf wear is caused by too stiff an arrow.  Try raising your brace height, not your nock point.  Bill

[xtrema312]

I have four different shafts, 50 and 100 brass inserts, and 100-225 points in 25 gr. incriments.  I can make up a lot of spines.  I have run arrows spined all the way down to 45# with the same issue.  It likes about a 60# spine arrow and shoots with no weak or stiff flight as long as I have the bare shaft tail high and hitting low.  I was working with a higher brace height when the string went.  When I get another string I will have to start working on it again.  Maybe the sting was part of it.

[kevgsp]

I had this problem too....drove me nuts.

My problem was tight nocks.  Went to a 10 strand string, diff serving, 2 tied on nocks, problem solved.

[xtrema312]

Thanks for that tip kevgsp.  I did have some issue with this bow and two tied nocks helped the first time around.  adding the low one was a big help.  The arrows are the ones I have been shooting all along, but I was thinking yesterday that they were a little tight compared to the fit of my LB and it's arrows,  and maybe I should open them up some.  I will make sure to do that on the next string.

[2elkhunt]

I had the same problem,and everyone told me it was my nocking point.I tried it and it did not help.So I got a couple new shafts and bingo no more shelf wear.

I was shooting 2016's and went to 1916's same length and nocking point.I'm not getting any wear now.

10 people can shoot the exact same bow and everyone will have to use a differant arrow or tip weight because no 2 people shoot the same.

[champ38]

Ive had the same problem (check shooters forum)..for some reason my ring finger was the problem. I was letting my fingers relax and roll open as I drew. Now if I take a deeper hook and make sure my finger tips are 90 deg. to the string at anchor, I get no shelf/rest contact. To check this, draw with 2 fingers (index and middle).. this drove me nuts for 3 weeks, tried different spines, shelf material, ect.  Good luck

[xtrema312]

For sure everyone is different.  I know there is something in my form.  Just about every used bow I get i have some shelf wear or high nock flight if I don’t move the nocking point up just a little, but it is usually not out of the normal range.  I have also had too stiff of shaft set-up once and worked through that.  This one just has me puzzled because I can’t get close this time around on it.  I have ruled out too stiff and too low of a nocking point.  The fact it shoots good three under tells me I am plenty high and should go lower split finger, but I get into the shelf when I do.  I am thinking it is a combination of my fingers, string, a little tight on the nocks plus probably the rest material making a little valley at the riser.  As soon as I get a couple new strings I will make some changes and see what happens.

[AkDan]

Bill, wouldnt raising the bh make the arrow act stiffer yet?  Shorter power stroke forcing less bend in the arrow...I'd say lower the bh if you think it has to do with spine and not something else.

[xtrema312]

Lower is stiffer and higher is weaker, but I think arrow speed is faster with lower due to the power stroke.  I don't know why the spine changes this way, but I think it has something to do with loading up the limbs more.  I tend to set brace for what the bow likes and fine tune with point weight and cutting shafts so I have not done a lot of wider range brace height changes to see how much effect it really has.

[JimB]

If you want to find ou what your problem is,and fix it,only make one change at a time and do a fair amount of shooting before you make any second change.If you want to work on form,do that but don't change brace height or nocing point height or any other aspect untill you have fixed or eliminated that as a source of your problem.

I've made this mistake in the past and it is the quickest way to confuse the issue.I have to constantly remind myself to slow down and check one thing at a time.

In Masters of the Bare Bow,Ray Beck says some people,in canting their bow,impart a kind of sideways torque to the string,with their fingers and that this causes the same identical shelf hitting as downward finger pressure.

It just seems like if the arrow shot fine with 3 under,and didn't with split fingers,the tune is good but something is happening in form,with split fingers.

Also,what kind of bow do you have and how long is it?If there is a finger pinch problem,that should be on the top finger,when shooting split fingers.

Good luck with it.I hope you will keep us posted.

[Bill Skinner]

I totally agree with JimB about making changes.  And as you pointed out it may be a combination of several minor problems that have turned into a major one that is difficult to figure out.  I think I would post a video on the Shooters' Forum.  There are several people who will do a frame by frame break down of your form and shooting.  They may be able to spot what is wrong with your setup, also.  Follow Terry Green's instructions about the different angles when you film.  Bill

[xtrema312]

JimB

Thanks for the info on the canted bow and finger torque.  I do cant the bow a fair amount and recently I noticed I was doing it more.  I  suspected maybe I torque the string with my middle finger pulling and my index finger hooked more over the arrow because the cant is more than my wrist will naturally turn out.  I have days when I shoot very comfortable and others where my index finger really takes some pressure and gets sore.  I have straightened up the bow some and paid a little more attention to this just recently. I will keep an eye on it.  I could have slipped back into this when shooing this bow again after it came back.  This very well could be the main issue.

I think there is more than one thing going on, but I agree the difference between the split finger and three under has to have something to do with it.  Those three under arrows were darts with bare shaft.  I should be able to drop the nock a little and shoot it split as far as tune goes.

My bow is 56" so it is short, but I notice no finger pinch with it. I have had bows that do pinch and this one doesn't seem to do that.  I can't tell any difference between it and my 62" bow.