Primitive Archer
Main Discussion Area => English Warbow => Topic started by: adb on February 07, 2013, 09:49:32 pm
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I have to admit it's been a while (no arrogance intended), but I made firewood today. I was tillering out a new warbow. Hickory back, yew core, ipe belly. 74" NTN. 1 1/4" wide at the center, 1 1/8" deep, tapering evenly to 1/2" nocks. I had it tillered to 125#@29". I only intended it to be tillered to 30", and I was looking for 120-130#. It had <1" of set.
I asked my wife to come and snap a few pics at full draw. I exercised it well, pulling it multiple times to 120#, no problems. To get a full draw pic, I had to hold it for 3-4 seconds to give my wife enough time to center the shot and let the camera focus. Catastrophic failure. After autopsy, I could see it blew a tip off. Top tip. I've been making my tips lighter over the years to improve cast and reduce handshock, but I definitely went too far and didn't leave enough meat on these.
Looking at the full draw, I can see the left limb (would have been bottom limb) is a bit stiff especially in the outer third. I would definitely have fixed this had it survived.
First pic: full brace
Second pic: 125#@29"
Third pic: my wife caught it just after it exploded. You can see flying chunks!
Rest of the pics: autopsy
Without the bitter, there is no sweet.
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That sucks! Better on the tree than in your hands at a 120lbs. A lot of good action shots lately!
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I wouldn't have to worry about it exploding in my hands! I can't fully draw 125# anyway. I can shoot 100# comfortably, but even 5-10# above that is impossible. The difference between 100# and 120# seems logarithmically different.
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Wow,
I heard an explosion recently and thought they were blasting up the road, now I know what it was!
Tough one, I too am consistently playing the how small can tips be game. I guess the rules get exagerated with draw weights that heavy.
All in all a good lesson in more more woops too much,
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ADB, what were the dimensions of your tips? they look fine to me....but point of reference is not there.
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Wow,
I heard an explosion recently and thought they were blasting up the road, now I know what it was!
Tough one, I too am consistently playing the how small can tips be game. I guess the rules get exagerated with draw weights that heavy.
All in all a good lesson in more more woops too much,
Yup! Scared the HELL outta my wife. ;D ;D She hit the deck! "OMG!! WTF???" Made a helluva bang! I won't be bringing this one to the shows Jamie... sorry!
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ADB, what were the dimensions of your tips? they look fine to me....but point of reference is not there.
I'll take a pic of the tip and post it later. Way too small for the weight, obviously! I think the problem was more the thickness than the width. I took too much off in the string groove, basically cutting it too deep. Live and learn.
It's a bit confusing in the picture. That's the top tip. It actully has two grooves. The top groove you can see in the picture is the stringing groove. The String nock is below that, and that's where it failed... in the string groove.
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What a bummer man :(
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ADB, what were the dimensions of your tips? they look fine to me....but point of reference is not there.
I'll take a pic of the tip and post it later. Way too small for the weight, obviously! I think the problem was more the thickness than the width. I took too much off in the string groove, basically cutting it too deep. Live and learn.
It's a bit confusing in the picture. That's the top tip. It actully has two grooves. The top groove you can see in the picture is the stringing groove. The String nock is below that, and that's where it failed... in the string groove.
Pics of the broken tip.
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Remember, that's the top tip, and the groove that's intact is the stringing groove. I'll leave a bit more meat next time!
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I see now....ya, tiny to start with, and the grooves musta been real thin....
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Yup... I know where the tip size limit on heavy bows is now!
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The positive I would take away would be, its been glued well to break in that fashion. How about full nocks next time though ;D
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The positive I would take away would be, its been glued well to break in that fashion. How about full nocks next time though ;D
Yup... I've never had a glue line failure. My nocks will have more meat on the next one! I doing the glue up for it today... same combo.
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That sucks about the brake. The tiller was very nice.
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Oh man :'( I feel your pain.
That looked sooo sweet too.
Forgive me if I'm stating the bleedin' obvious here
I'm sure you can see for yourself you'd left virtually no horn at the nock.
I generally have very little groove a the side of the tip, especially if you are making 'em reall skinny, After all the string moves up and down along the side as the string angle changes so it doesn't want to sit in a groove.
Dunno if I'm getting fanciful now, but if the string is tight in a groove up the side of the nock, then as the string angle changes it will be sort of trying to lever the tip over towards the back of the bow.
See attached pic... ok it's only from a weedy 50# bow but it shows what I mean (btw it's 1/2" wide at it's widest point)
Maybe that's why full ELB horn nocks are a good idea? you retain a full circle of horn where the string sits* and thay can still be pretty skinny.
Oh dude, that must've felt like a kick in the guts.
Again oppologies... I don't mean to treat you like some newbie..... (tugs forelock and backs carefully away from the keyboard)
Del
* I have on occasion had 'em where the wood peeked through a tiny bit at the side.
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No offense Del! The reason I post failures is to get feedback about alternate ways to fix mistakes. I will definitely heed your advice. I certainly cut the string grooves way too deep.
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Dek, I love your nocks..very cool!
So you don't groove the sides at all? maybe I'll rethink how I do that on ELB's now...
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Dek, I love your nocks..very cool!
So you don't groove the sides at all? maybe I'll rethink how I do that on ELB's now...
Sometimes there's a hint of a groove, but I take care to look at how the string sits at brace and full draw.
Here's the top nock of the same bow, you can see the groove goes round the side a bit more on this one.
Del
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I'm also going to re-think cutting the side grooves too deep.