Primitive Archer
Main Discussion Area => Bows => Topic started by: Tuomo on April 13, 2021, 02:41:52 am
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Let's have a little guessing - what is (was...) maximum draw length for this bow? I know the answer but what you would say?
Sugar maple back, black cherry belly. Length 73,6 inch, max width (handle) 1,12 inch, tips 0,4 inch. Pretillered before gluing, tapered but not really tillered. Backing strip is cut straight from a big plank, good grain but not near perfect.
So, what was the maximum draw length and draw weight before exploding?
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Really depends on the quality of the back and the thickness of the limbs. where you trying to break it? I would guess somewhere over 30-35"
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I made a mistake with this bow, so the only option was to test, how strong it really was. I was surprised.
It was about 47#@28" – but the final draw weight and length were much more.
Result after maximum draw length:
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I made a mistake with this bow, so the only option was to test, how strong it really was.
That must have been a really bad issue, most mistakes are salvageable. It looks like there weren't any serious weak spots, it seems to have broken everywhere simultaneously. It would take a lot to give cherry the kind of set that one piece has. There was a guy here not long ago that blew an oak bow at 40 some inches
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First picture looked good. Not sure I could make a great guess but it looks like you answered your question. Was it taking set before the break?
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I would guess somewhere over 30-35"
More...
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Dunno :)
I did a similar thing with an elb that wasn't doing what it was meant to...it went to 40" and still didn't blow, my tillering set-up was maxed out haha I still have it somewhere, that was a hickory/ipe bow.
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it went to 40"
More...
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it went to 45"
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If it went to 40" I dont think there was much wrong with it lets see 47@28" 50@30, 70@40" or near abouts. Hope you had your skid lid on when that Sucka went Bang!
Hedge~
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it went to 45"
More...!
It measured 83#@43" – and it had still a lot of more life remaining.
Here is 45" draw.
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Lol!
Looks like maple and cherry is a good combo.
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Interesting experiment.Those are every day Howard Hill poundage shooting draw weights.
Your bow looks afterwards like a sinewed D/R to 6.5" red cedar from a stave I did years ago.When they go they go off with a big bang.
The hidden culprit that can infiltrate a black cherry many times with time surviving when being over stressed is that it'll chyrsall or fret on the belly.
I have an awful pretty 64" sinewed on only the working limbs black cherry holmgaard that chrysalled just a little after a couple thousand shots through it.Still shooting it though and it still looks healthy holding 4" of reflex at rest.
If a person is paying attention to the draw weight as you pull farther and farther on the tillering tree and the draw weight starts decreasing that's the sign it's degrading and getting ready to blow.
That sure is a heck of a long draw though.
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The hidden culprit that can infiltrate a black cherry many times with time surviving when being over stressed is that it'll chyrsall or fret on the belly.
The interesting thing was that there were zero, not a single fret or chrysals, nothing. It just took set, about 4–5".
But, we are now at 45" draw and it is still going strong! But how far?
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You shoot em long enough that way over stressed and it'll happen even though it does'nt show immediately.
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How do you know how much set it took if it blew? Also, the left limb is bending way to much. I think it blew at mid left limb first.
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How do you know how much set it took if it blew? Also, the left limb is bending way to much. I think it blew at mid left limb first.
That was set in 45" draw. And you are right. But this was just pre-tillered before gluing, not really tillered, because it was not going to be a bow, unfortunately.
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Good to know there’s a margin of safety but this doesn’t tell too much else. Generally we care far more about when a bow breaks down before opposed to when it actually breaks.
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I’m curious why it was not going to make a bow. What was he initial mistake made?
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I’m curious why it was not going to make a bow. What was he initial mistake made?
I was making three similar bows at the same time, so I was rushing... So, I chipped off a bit too large piece of the tip of this bow. Of course I could have glued it back but instead of that I wanted to test, how far I could draw it. I didn't need that kind of bow and I couldn't sell it either. I have tested this way many bows and my best has been about 43 inch. This bow broke (!) the record.
So, it broke at 50 inch draw! About 105 pounds. Tough stuff. I specified them to 28 inch draw and it is good to know that they can handle a tiny overdraw. There are always those long hand guys, who want to "try" the bow.
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Good job! Impressive!!!
May I ask you about the maple backing you used? Was it edge grain or flat sawn (with a continous ring in the back maybe)?
I have used a lot of ash backings edge grain but often thought about using maple (edge grained).
cheers
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Thanks!
The backing was flat sawn sugar maple, straight from the good blank. So no continuous ring but good enough. I have made a lot of this kind of maple backed bows and I really like them. I think that maple, ash and hickory are the best white wood backing, as it is of course well known fact.
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looks like these backings are highly underrated. Everybody is using just boo. I like the tought of being able to use my local woods for my builds. thanks Tuomo (-S
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looks like these backings are highly underrated. Everybody is using just boo. I like the tought of being able to use my local woods for my builds. thanks Tuomo (-S
If I recall correctly, I think Marc has had good results with maple over other wood backings.
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you will find that in general bamboo will give a bit more snap to a lam bow, that is not to say woods backing are inferior just different. Horses for courses. Of course boo backings follow one ring :) A lot easier to find good boo then to search through wood stacks for a good board