Primitive Archer
Main Discussion Area => Bows => Topic started by: GaryL on October 04, 2018, 07:59:03 pm
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Hello Everyone,
Last week I posted some photos of my first board bow and some of the issues I had, one of which is was trying to hit the weight, I came in wayyyyyy under!
I am going to build another one and try again but I thought in the meantime I would take the advise of a response I got on my earlier post and shorten the bow and re-tiller.
I built it long at 70" so I trimmed off 3 inches from each end resulting in a 64" bow.
When I originally built the bow it took some string follow and my real question is, once the belly fibers have been compressed and a bow takes string follow can it be reversed with heat or will it be permanently set? I was thinking about trying to straighten it out before re-tillering but not sure if its just a waste of time or not?
At this point I am just experimenting, I figure its better to learn on a junker and be better prepared when I try to build the next one!
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Gary, set occurs either by the use of "wet" wood or overstressing the wood. Most woods are stronger in tension than in compression so set is inevitable. The degree of set is in the process, not over stressing the limbs as you tiller. Heat treating does increase compression strengths in many woods but it should be done before the damage is done. You can reverse the set temporarily by heat treating but I doubt it would last. The damage is already done.
To keep from coming in low in draw weight pull your bow to the desired draw weight as you tiller. When you get a few inches from full draw and everything is good you are as good as being there. Now you have a few pounds to work with for slight adjustments and finishing.
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You can get some improvement in the set but mostly IF a bit of retillering is involved.
Basically heat treating can gain say 10# and the bow can be pulled straight during this. IF some belly wood is then removed to get back to original draw weight you will removing some of the crushed set wood and bringing new wood into play.
Generally you don't get something for nothing...
https://bowyersdiary.blogspot.com/search?q=hickory+challenge (https://bowyersdiary.blogspot.com/search?q=hickory+challenge)
https://bowyersdiary.blogspot.com/2013/03/hickory-challenge-result.html (https://bowyersdiary.blogspot.com/2013/03/hickory-challenge-result.html)
Del
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I agree with Pat. Further, the wood at the last inches of the tips usually doesn't bend much and is not likely to be damaged. Thus, you can try to add a little reflex there.
I forget how much set you got, Gary. <2 inches is acceptable.
I think piking just exacerbated any problems present so I am not a fan.
Jawge
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You can get some improvement in the set but mostly IF a bit of retillering is involved.
....
https://bowyersdiary.blogspot.com/2013/03/hickory-challenge-result.html (https://bowyersdiary.blogspot.com/2013/03/hickory-challenge-result.html)
Del
Wonderful experiment and good write-up. Thanks.
I usually start with longer staves than necessary just to make them easier to pull during tillering. So long as I don't forget to keep the unbending tips longer than intended, things work out all right.
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Originally heat treating was a method of reviving bows according to the original PA article which was an excerpt from an older magazine.
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Type of wood? the
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If a bow is wet or a little too high in moisture when it was tillered sometimes it will heal up a bit when dried out. As said above the best place to look for more wood is near the handle area and fades because you get a lot more bend from that area. Cutting a 70" bow down to 64" will cause it to take considerably more set unless you can find some places that were not bending enough to start with. I would just heat treat and do my best to get everything bending possibly even lower the weight a tad.