Primitive Archer
Main Discussion Area => Bows => Topic started by: Mark Smeltzer on February 02, 2014, 08:15:03 am
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Well today I was shooting my newly built Yew recurve and I accidentally dry fired it and here are the results. It was completely my fault, I was using a different string that I had not put serving on yet so the nocks were super loose on the string.
On the plus side....I gained a giant set of calipers and I get to make a new recurve.
Mark
(http://i38.photobucket.com/albums/e125/MDS65/brokenrecurve007_zps6d093c0c.jpg) (http://s38.photobucket.com/user/MDS65/media/brokenrecurve007_zps6d093c0c.jpg.html)
(http://i38.photobucket.com/albums/e125/MDS65/brokenrecurve006_zps24ebca6b.jpg) (http://s38.photobucket.com/user/MDS65/media/brokenrecurve006_zps24ebca6b.jpg.html)
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Oh sh#@!! On the plus side...Now you have to make another one! :laugh:
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Sorry to see that.
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could you not rework it and use takedown sleeves as it has broken righ at the handle. it would be a shame burn that one.
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Do you think that could be glued considering the location of the break?
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could you not rework it and use takedown sleeves as it has broken righ at the handle. it would be a shame burn that one.
Bummer! I thought takedown sleeve?
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Thats brutal! :'(
I just delivered a bow to a family member last night and we talked about the consequences of dry-firing or even using arrows too light in weight. (He's a wheelie guy but wants to get into trad.)
I also blew one up that was very close to finishing when I cut the string with a wayward scraper. looked ok until I took it out of the vice....blew the riser off and split in a similar location at the fade.
It happens I guess. :-[
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Yea, it's a bummer but stuff happens. Right the way it sits the sinew is undamaged and holding the back together. I dont think it can be glued together and hold. I may give it another look.
Learned a good lesson on that one!
Mark
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Tough break right there.
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that sucks.
I dry fired a fibergl@$$ recurve not too long ago- had robin-hooded an arrow, didn't know the nock was damaged. It shattered. one of the phenol overlays flew about 40 yards downrange.
that really sucks.
A takedown sleeve?
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Ouch :o That was a great bow to
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Man that's a totally bummer. That was a gorgeous bow.
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Sorry man - that is a bummer.
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Awwwwwh man! This is the first results I have seen from dry firing. Great attitude with the caliper comment! Would love to find out you figured out a fix for her!
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I dry fired a glass recurve once years ago and the bow was fine, I guess a selfbow may have harder time withstanding the stress.
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I've been told that would happen, but have never seen the result. thanks for posting
chuck
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:o
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It is so sad when one so young and beautiful is taken from us before it's time. A tragedy, indeed, when you reflect on the life they would have had together and the wonderful times they will never get to live out.
I think this calls for a few moments of silent reflection or prayer. May this senseless tragedy never happen again.
John Halverson
President,
B.A.D.F.
Bowyers Against Dry Firing
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Now I'm laughing thanks JW.
Mark
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I dry fired a gull wing osage/sinew about a month ago. I am not sure how I managed to not actually knock the arrow. It scared the crap out of me and the hand shock stung my hand but the bow is no worse for wear.
After feeling the after affects of the dry fire I now understand how it can damage a bow.
Patrick
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That sucks so bad. Thank you for sharing though, it really shows the effects dry firing can have.
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Man, that's a real heart breaker, makes me ill and it's not even my bow. My condolences Mark
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Dang, and I really liked that bow. I know how you feel, I broke a favorite bow a couple of years ago by dry firing.
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I saved one like that with a sleeve. worth it.
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Thanks for the kind words, I'm a little bummed but it was my own fault I knew those nocks were way to loose. I'm going to look at it again and see if I can save it. Funny thing......this is the second time that bow has been in two pieces, it started off as two billets. Thanks.
Mark
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Forget the sleeve it's too close to the fade. You need 2 inches inside a sleeve.
It can be fixed tho! What you need to do is to use another piece of wood 8 inches long. Cut both ends of it to be the male members of a v splice. The female cuts should be into whats left of the handle and of course into the limb/fade. A v splice will take the bend into the fade no problem. Heck it will look butt ugly but will work and at least it will have a story to tell. All Turkish hornbow are joined this way just in case you think i'm suggesting something tha
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t won't work!
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You would likely still want to re-sinew the back of the splice and add a thin veneer on the belly side in that scenario.
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I'm thinking what Mike said is right about the sleeve fix, just not enough there but I dont think I want a butt ugly bow hanging around so I'm going to leave it as is for a while to remind me to never be so lazy (not putting serving on that string) again.
I'll go to the wood stash and dig out some more Yew and start again.
Mark
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You can salvage the bow but not with a 2 piece take-down rather a 3 piece like the one I wrote about in the PA magazine many years ago
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That is a real bummer man! It was a sweet looking bow.
Thanks for the lesson on what happens with a dry fire though.
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Oh my - that sucks. That was a really fine bow.
But I'm with Mike, if a the 2 pieces didn't hold together try the 3 piece project.
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Bummer. You still have 2 working limbs... you just need a riser. That being said, I wouldn't do it. Instead, I'd keep this bow around to show people what happens if you dry fire a bow.
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I looked it over and there may be ways of fixing it but it just wont be the same and I don't have any interest in making a Frankenstein's monster out of it. I think I will leave as is and do what adb says.
Mark
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What was your string material? Or are you saying the string actually jumped out of the nocks?
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Pat
I use B50 and the first string I was using was 12 strand because that's what i had already for a different bow that was the same length. I wanted a 10 strand so I made one and took a few shots with it before I served the string at the nock point. Without the serving on the nocks were loose and I lost focus for a second and the arrow fell off the string as i released....and the rest is history
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I think this shows that a stretchy string is actually worse in a dry fire situation.
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Could be, I dont want to be the one to do all the testing though :laugh:
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I think this shows that a stretchy string is actually worse in a dry fire situation.
How? I believe a bow fails from a dry fire when the stored energy that is normally transferred to the arrow at release, is returned to the bow's limbs in the form of excessive vibration. How would the string material make a difference?
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Yea, not sure I completely understand that either, maybe Pat will elaborate.
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Ahhh! I see now, it was the arrow nock that did the dirty misdeed. I was trying to think how the string could come off the limb nocks. *smacks forehead*
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A stretchy string allows way more "bulge" of the bow limbs forward without the arrow. The string probably approaches a degree of virtually breaking in this scenario.
Yew bows used to be known for breaking when the string broke.
Vibration might delaminate a bow but it's not going to vibrate a bow so that it severs in one spot.
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Got evidence of that? I would tend to belive the stretchy string would absorb the vibration like a dampener. That's why natural strings are softer sounding on guitars than steel strings.
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Pat are you saying that a stretchey string will allow the limbs to travel further away from the shooter?
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Of course they do. That's why arm or even wrist slap is so evident.
A stretchy string may absorb vibration but it also allows the creation of more vibration/limb movement after the dry-fire.
A non stretch string doesn't allow the limbs any room to move.
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Makes sense but in this case those limb tips (recurves) were pretty narrow, I suspect that the string could have slammed hard enough to slide off to the side and out of the groove in the underlay. That to me would explain why/how that bottom limb got to be more than a 90 deg angle from the handle. I'm thinking the string didnt stretch that much.
Mark
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I would have to disagree with Pat. A stretchy string is easier on a bow if dry fired. I have, unfortunately, had the misfortune of having a few dry fires, mostly due to arrow nock failures and I was using FF strings on most. In every case the FF strings destroyed the bows while some bows with the dacron string survived.
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What was the type of destruction? Separation of growth rings/lams, broken in half ,nock failure etc? This is very interesting.
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Makes sense to me Marc. A stretchy string would absorb a lot of energy before the limb tips hit home. a good analogy would be bungee jumping, think about jumping off of a bridge with a non stretching rope. I bet that bow was smoking fast which also made it less likely to survive a dry fire.
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I made the last 6" very narrow on that one hoping to lighten the tips and get more speed out of it. It worked, it was very fast and no handshock but in doing so I think the tips may not have been as stable as some other recurves I've made.
I really do think that when the string slammed that hard it slipped past the grooves in the underlay and allowed the limbs to over travel as bad as they did.
My opinion is in this case it would not have mattered either way. I'll try it again but modify the string grooves to be deeper and more open maybe.
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It would have to miss the grooves by twisting than actually "slam past them".
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Yea, thats what I'm thinking. The string wasn't hitting right in the bottom of the groove and the dry fire just was too much. Weather it was twisting due to instability or just misalignment, thats what I think is why it failed in that way. The limbs on that were only 1 1/8 at the widest part. It was a bit of an experiment just going for all out speed.
Live and learn, I'll try that one again.
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What was the type of destruction? Separation of growth rings/lams, broken in half ,nock failure etc? This is very interesting.
One of the FF failures was exactly like Mark's Yew bow. A couple of others had the string snap the overlays and travel down into the limb several inches. Nasty stuff
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Of course they do. That's why arm or even wrist slap is so evident.
A stretchy string may absorb vibration but it also allows the creation of more vibration/limb movement after the dry-fire.
A non stretch string doesn't allow the limbs any room to move.
Ok, I see how you have arrived at your conjecture. My conjecture would arise from thinking of this as someone bungee jumping. You hit the end of the lenght of elastic rope long before you stop moving, and the energy of deceleration (actually reverse acceleration) is slowly released. Make the same jump with a sisal rope, which has elasticity, albeit significantly less, and the reverse acceleration happens over a much faster period. Ouch. Now make that rope out of numerous strands of FF, zero stretch. Worse yet. The shock of immediate stopping has to be absorbed somewhere?
Is there any high speed photography of how a bow limb behaves when it hits home under FF vs Dacron?
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I can definitely see the nock scenario failure where it is more of the splitting action but less so the limb failure.
The string definitely stretches with Dacron but the allowed limb movement is much greater. With a no stretch string, the limb just doesn't have anywhere to go.
The shock can still be absorbed by a no stretch string without it actually stretching, no?
If you use a fastflite bungee cord with a Kettlebell as the weight and it doesn't break the cord on the drop, that energy was still absorbed.
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Yup, kinda like a long drop with a short rope around the neck is absorbed. What does that shocked energy do to the neck/limb?
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You're comparing vastly different materials and scenarios. For all intents and purposes, the neck is the weak link in part of the rope.
A well made bow has no "neck".
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Every time I hear that cracking sound, it breaks my heart.