Author Topic: Hinge correction possibilities  (Read 2384 times)

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Offline Daniel

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Hinge correction possibilities
« on: September 29, 2021, 11:12:47 am »
Hi,
First time poster here, so before anything else I would like to thank all the contributors to this forum for creating such a great resource of valuable information.
I'm not a native speaker obviously, so please pardon my English.
After finishing more or less successfully couple of bend-in-the handle D bows, I recently attempted a Sudbury style design.
The wood is hazel, 66 inches NTN, I want it to be around 40# @28.
After some work on it I let the bow develop a hinge just right in the area of a rather big knot  in the right limb fade. It even looks like it took some permanent set in that spot.
Now I'm stuck. Should I carry on with tillering, without touching the hinge spot and hope it somehow works out?
Or should I try to heat-treat the area and get rid of the reflex-deflex around the knot?
Or should I just throw it in the stove and start another one?

The pictures of unbraced and low braced bow:




Thank you for any advice and suggestions.

Daniel
Daniel

Offline Don W

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    • diy.timetestedtools.net/
Re: Hinge correction possibilities
« Reply #1 on: September 29, 2021, 01:51:01 pm »
I'm pretty new to building bows (comparatively) and I do what you've done quit often (although I am getting better about it). I always try to save it, and usually do. I think of it as the bow teaching me patience. It usually happens when I get in a hurry.

If it's early enough in tillering it will likely be ok, but if it's to close to the desired draw weight you can decide to lessen the desire, or pike (shorten) the bow a bit. I almost always chose piking, but either way works.

I've only tried heat treating a specific area once, and it worked out great, but it was closer to the fades and center of the handle area. It should work, but if I was going to do it on this bow, I'd heat treat the whole thing. It still helps because you have a larger range to work the other areas for weight.
Don

Offline TimBo

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Re: Hinge correction possibilities
« Reply #2 on: September 29, 2021, 02:02:22 pm »
Welcome to PA!  Are you sure it took set there?  It looks like the kind of spot that would be tricky to judge unless you could compare it with the original profile before you started to bend it (either a photo, or if you had traced it on paper, like I always forget to do...).  If it were mine, I would avoid that spot, get everything else bending evenly with it, and then evaluate the weight.  I have had some luck with spot heat treating, but doing it all at once might be better since I think you will want to heat treat hazel anyway. 

Offline Daniel

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Re: Hinge correction possibilities
« Reply #3 on: September 29, 2021, 02:30:57 pm »
Thank you guys for your replies.
Yes Don, I definitely feel I was inpatient working through the belly side of that hump.
TimBo, unfortunately I don't have any pictures of it before bending, but I remember it had slight reflex in that limb, so I suppose it took some set there.
I will follow your advice to continue tillering, I may have few pounds to work with.
Just one more question, do you think I should scrape some wood also from the left (closer to the handle) side of the hinge, or work only on the outside part of that limb?
« Last Edit: September 29, 2021, 03:19:17 pm by Daniel »
Daniel

Offline rps3

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Re: Hinge correction possibilities
« Reply #4 on: September 29, 2021, 02:59:15 pm »
I'm not sure I'd call that a hinge.

Offline TimBo

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Re: Hinge correction possibilities
« Reply #5 on: September 29, 2021, 03:11:55 pm »
It does look kind of thick to be developing a hinge there.  Can you see/feel it moving in that spot?  If it already had some deflex there, you may be in good shape. 

Offline Daniel

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Re: Hinge correction possibilities
« Reply #6 on: September 29, 2021, 03:18:55 pm »
TimBo, I'm sorry, I meant I remember the limb had slight reflex in it. I corrected it in my post.
Daniel

gutpile

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Re: Hinge correction possibilities
« Reply #7 on: September 29, 2021, 04:05:45 pm »
I'm not really seeing a hinge per se.. if you think it is hinging right out of fade, that would require some serious wood removal at that point.. it still looks kinda thick from what I can see.. i think that hump is throwing you off.. I'd continue tillering slowly and keep an eye on it.. even if you think it has taken slight set there..gut

Offline PaSteve

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Re: Hinge correction possibilities
« Reply #8 on: September 29, 2021, 07:12:44 pm »
I don't really see a hinge, either. I agree with gut... continue tillering.... I've probably learned more from bows I've screwed up as opposed to successful builds. Good luck
"It seems so much more obvious with bows than with other matters, that we are the guardians of the prize we seek." Dean Torges

Offline Morgan

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Re: Hinge correction possibilities
« Reply #9 on: September 29, 2021, 08:55:57 pm »
I don’t think it’s a hinge either. Them bumps on the back at knots can throw your eye off.

Offline Daniel

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Re: Hinge correction possibilities
« Reply #10 on: September 30, 2021, 11:55:20 am »
Ok, seems like I mistook  a hump for a hinge  :)
I'm going to continue tillering the bow and see how it turns out.
Thank you all for your input!
Daniel

Offline TimBo

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Re: Hinge correction possibilities
« Reply #11 on: September 30, 2021, 01:36:16 pm »
On the other hand  >:D you do want to watch that spot and proceed with caution - wiggles that near the handle can certainly mess with your tillering eye!  I do think you have an excellent start though - please post your progress.

bownarra

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Re: Hinge correction possibilities
« Reply #12 on: October 01, 2021, 02:24:26 am »
A drawn picture would really help. Without seeing how itt is moving we can't really tell for sure.
Whne asking for tillering help post one pic of it unbraced, one strung and one drawn picture. :) and ideally one before you bent it!

Offline Daniel

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Re: Hinge correction possibilities
« Reply #13 on: October 02, 2021, 01:53:26 am »
Yesterday I was able to work on it and it's bending now 26'' @ 45 lbs. Sorry for the poor photo, but here it is drawn to 26''.

I will work on the tiller some more, but probably won't push it further to 28''. I made the handle a bit too long and even now at 26'' of draw length I think the limbs are working quite hard.
Bownarra, I will follow your suggestion next time, definitely makes sense. For now I have only the picture above.
« Last Edit: October 02, 2021, 01:57:14 am by Daniel »
Daniel

bownarra

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Re: Hinge correction possibilities
« Reply #14 on: October 02, 2021, 02:37:27 am »
Sorry also forgot to mention that the way the bow tapers in width is very important. different tapers need different tillers to stress the wood appropriately.