Primitive Archer
Main Discussion Area => Bows => Topic started by: straightarrow on January 25, 2011, 12:25:23 am
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Just wanted to post a comment about a D bow my friend was working on. I was mentoring him on his second bow while still learning myself. The wood we were working with was hop hornbeam. The kid has a good eye for tiller and things were going quite well. We got towards the end and I told him to take the bow home and shoot it a couple hundred times to see if the tiller changes. After a few days he brought the bow back... and rechecked the tiller. It looked good and we didn't see any changes so he started the finish work. When it was all done and ready to post he shot it a few more times. We started taking pictures and typing up the post and that when we realized the tiller changed and a hinge was starting in the upper limb. He ended up deleting the post and we are going to re tiller and make it right.
So....What would any of you guys done differantly...or is that just the nature of the beast
Jon
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Wood is organic and unforseen things happen with wood sometimes...but generally it is pilot error! Pics of the bow as it is now will help determine where the problem might be. Unbraced, braced and even drawn.
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if its the one im thinking it is(and it is gone now)
then if i remember right it looked like he could of had more wood bending out of both fades a little more
the upper limb looked to be doing most its work midlimb on that bow too
ive made many hickory and hhb bows with prop twist(which he stated it had) and that wont cause it to change tiller like he suspected
my guess is that upper limb was thinner in the area that the tiller changed or the hinge showed up in
it may not have been enough of a thickness differance that you could easily spot it,but once stressed from shooint the bow in it showed up
but like Pat said if we could see some more pics again then it would be easier to help identify the error
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You are correct sailordad that was the one. There was a hinge forming in the upper limb in the fade area. I know where the mistake was made. Toward the end of tillering he was scraping to get the wieght down which stiffened up the handle area. It should be a easy fix...he will just have to refinish the bow. Not sure if it was pilot error...pat. It seems the hinge formed after the bow was complete. Maybe he didn't shoot enough and the tiller didn't settle in. When things get straightened out I will post before and after pics. I do know things were hurried towards the end to get the bow done....so it just goes to show that going slow will help catch mistakes. A valuable lesson was learned and was one that I learned not long ago.....SLOW DOWN
Jon
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What method of "stringing the bow" are you using? Art
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I had a look at the bow and I wouldn't call that a hinge. The limb has a nice smooth bend to it. The lower limb is a bit stiff.
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Having uneven M/C in your limbs can cause tiller change after finished. This could be before or after the bow was completed. Standing your bow upright can create uneven M/C in your limbs...........Art
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Pics would be nice. But hinges don't just happen after the bow is broken in. Jawge
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I'd guess not enough exercise between wood removal.
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This is very similar to a thread I posted a while back, it was an Ash flatbow which did it to me.
I could barely believe it, the lower limb went way out of kilter and I had to lose 10 pounds in draw weight to get the tiller back even.
Guys on here reassured me that they'd seen it too.
I heat treated it which almost restored the original draw weight.
Del
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That push/pull method of stringing will wreak a tiller real fast if one isn't aware of where the hand pressure is needed. Usually the lower limb if strung upright. You use that method Del? Art
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That push/pull method of stringing will wreak a tiller real fast if one isn't aware of where the hand pressure is needed. Usually the lower limb if strung upright. You use that method Del? Art
I've made enough to know how they flex and how to string 'em... it's the guys who don't make 'em that you have to watch.
Longbows I'll lave the lower nock against my foot while I pull on the grip and push on the upper limb and slide the string up.
Some flatbows which are too wide to slide the string down the limb (back of the bow facing the ground), I'll have the lower nock pressing against the ground while I press my knee against the grip and pull the top limb up and pop the string on. I once had a guy tell me 'that's not how you string a bow'... I told him, I made it so I knew how to string it (But not quite so politely :o)
Whatever I do, I make sure both limbs are bending and I only use enough pressure to just get the string on.
Del
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I use the method of stringing that Del talks about. Here is the pic of the bow...
Jon
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Oh you tease...
I'll tell Mrs Cat of you and then you'll be sorry.
She used to be a teacher and one of her hard stares can cut through granite :o
Del
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I think you posted in the wrong place...Del...lol
I think the bow should bend more thru the handle on the upper and lower limb?? What do you think??
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before anyones asks here is the unstrung and strung pic
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"it's the guys who don't make 'em that you have to watch."
Probably have to watch me pretty close then ;) ;D! Art
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@ Straightarrow:- Yeah sorry, I think my paranoia was kicking in...
I'll be ok once I've had a cat nap and a glass of wine ;).
I think you're right, a bit more bend near the grip and the top limb is looking a whisker weak about 2/3 the way out from the grip, you just need to unscrape it a bit there ::)
Del
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If you scrape the lower limb about mid limb it will bring the top limb back in line. More wood working closer to the handle would be nice but not necessary
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What Marc said. There is no hinging in that bow. About stringing...I've seen guys use the push pull grabbing the upper limb several inches above the handle to make stringing easier and then wonder why the limbs shifted tiller. Grab it at the handle or use a stringer. I've heard people talking about not exercising the limbs between wood removal sessions. That's a sure way to end up with an out of tiller bow after a couple hunnert shots. Ok gettin' of the soapbox before I fall off. :) Jawge
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im gonna have to agree with the last few the upper limb looks beautiful to me its the lower limb thats not working . get it working and if weight falls too much pike it a little . jmo
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Well I am glad to hear that bow is not hinging. When he first posted it was suggested that it was. The power of suggestion had my head spinning on this one. I am grateful for the responses because my plan of attack was backwards and I would have had that upper limb bending even more. We will get that bottom limb bending first and I will let him decide if he wants it to bend through the handle anymore. He still has some weight to work with (64#@25") so we should be good there.... Thanks guys I appreciate it. When the young man gets it finished we will post the finish pics again.
Jon
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hey guys sorry i didn't comment earlier but i agree on making the bottom limb bend more now that it was mentioned the top limb does look good i will defiantly take all the advise given to me and fix the bow this was a great learning experience for me and i appreciate all your guys help :)
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I agree with what has been said about scraping the bottom limb a small bit to bring the elusive tiller between limbs back. But the most important factor is how does it shoot?