Primitive Archer

Main Discussion Area => Bows => Topic started by: simk on April 24, 2022, 10:15:35 am

Title: max draw length?
Post by: simk on April 24, 2022, 10:15:35 am
what do you guys think - how far can I draw this bow before it explodes?
Its boo-backed-yew, tillered to 38# @ 26", 63.5"ntn

???

 :)
Title: Re: max draw length?
Post by: bassman211 on April 24, 2022, 11:15:42 am
I wouldn't ruin a perfectly nice bow to find out, but it's your bow ,and your call. If your glue line holds maybe the low 30's, but that is nothing more than a wild guess. Be safe when you try it.
Title: Re: max draw length?
Post by: simk on April 24, 2022, 11:22:32 am
Bassman, this bow wasnt so nice. It was made from a crooked piece of bellywood. I did heat straighten a lot before glueup. While tillering all the twists came back. It was a pain to tiller and it hurt my heart to see all the heating work just slowly dissapear. Thats why I degraded this one to be experimental test bow. I always wanted to do this with a bow and this one now just was the right one. It was for maximised learning effect. .
Any more guesses? :)
Title: Re: max draw length?
Post by: Pat B on April 24, 2022, 12:14:17 pm
You might be surprised how far it will bend but will it recover or will it develop lots of string follow.
Title: Re: max draw length?
Post by: mmattockx on April 24, 2022, 12:44:38 pm
With a bamboo back and a yew belly I wouldn't be surprised to see it not blow at all and just crumple the belly up into massive compression failures.


Mark
Title: Re: max draw length?
Post by: bradsmith2010 on April 24, 2022, 02:01:22 pm
depends on how dry it is too,, :)
Title: Re: max draw length?
Post by: diliviu on April 24, 2022, 03:58:40 pm
36?
Title: Re: max draw length?
Post by: Kidder on April 24, 2022, 09:25:05 pm
I’d bet you can get 40 out of it, if it blows at all. I’d also add to the guessing game by saying your point of failure will be the right limb just outside from the fade. And I’d wager 11 schrewtbucks if anyone wants to take me up on it.
Title: Re: max draw length?
Post by: superdav95 on April 24, 2022, 10:19:48 pm
I’ll say mid limbs at 34”
Title: Re: max draw length?
Post by: Tuomo on April 25, 2022, 03:19:21 am
About 45"

And it does not explode, rather collapses.

I had similar case, wanted to test maximum draw length:

http://www.primitivearcher.com/smf/index.php/topic,69979.0.html

50" for 73,6" bow., length/draw length ratio was 1.48.
Title: Re: max draw length?
Post by: simk on April 25, 2022, 03:27:54 am
thanx for guessing  :) my guess was 36 to 37" until fatal problems.
In fact we had plenty fun drinking beer and trying to brake this bow...alone we didn't succeed. We just stopped the experiment after reaching 104# @ 44". At this point there was no sense to proceed any further and we decided to give the gift of life to that bow; its retired now with the medal of honor!
there wasn't too much set until around 37" draw and most of the set kicked in in the last inches of draw. after the test it pulled 28# @ 28". but the tiller didnt change at all during the test. the first pic I posted above was made after the testing.
this piece of wood came from a dead standing yew tree. It was full of drying checks that I filled with 2k before the glueup. It also had a yew-plug in the main bending zone and also showed wormholes  ;D
But it really seems to be amazing wood. the wood itself does not show any signs of stress after the test. Before this test I was thinking about trashing the rest of this log; now I think I will keep it and make another bow...trying to avoid the twists.
side remark: after the test I realized the test was done with a string made only from 6 strands of bcy452x  ;D
cheers
Title: Re: max draw length?
Post by: simk on April 25, 2022, 03:38:03 am
that was a good guess tuomo  :OK
Title: Re: max draw length?
Post by: simk on April 25, 2022, 03:46:14 am
that was interesting fun  (-S
Title: Re: max draw length?
Post by: Del the cat on April 25, 2022, 03:53:58 am
Wow... and wow :)
String angle is getting a tad extreme... in danger of pulling the nocks off!
That's a testament to the properties of Boo/Yew as a combo,also the glue and your bowmaking skill.
I'd fully expect that draw if it were a light weight, but getting to 104# ??? Did I mention "wow" !?
Great test :)
Del
Title: Re: max draw length?
Post by: simk on April 25, 2022, 03:57:26 am
thanx Del  :)
I don't think FG could do this  ;)
Title: Re: max draw length?
Post by: Del the cat on April 25, 2022, 04:00:01 am
thanx Del  :)
I don't think FG could do this  ;)
What is this FG of which you speak ;)
That's gotta be the most entertaining post I've seen in a while. That bow deserves to relax in your fave armchair with a cold beer :)
Del
Title: Re: max draw length?
Post by: simk on April 25, 2022, 04:20:12 am
...maybe should have recurved it some, hahaha  ;D
Title: Re: max draw length?
Post by: Hilongbow on April 25, 2022, 05:30:10 am
That's awesome! I did a similar test last year on an old guava bow that didn't turn out so well (lots of set). I could pull it until the string pulled off the nocks, no damage at all. I ended up breaking it by setting the nock on the ground and putting my full weight on the bow. The limb tip bent almost too the handle before it finally broke. This bow never even had a finish on it, and had been left out in the rain overnight a few times. I think sometimes we underestimate the ability of wood to handle bending. Sorry yours didn't turn out the way you wanted it too. I really like the side profile.
Title: Re: max draw length?
Post by: bassman211 on April 25, 2022, 09:54:35 am
Awesome test, and shows just how well that bow is tillered, and your over all skills as a  bowyer. Congrads.
Title: Re: max draw length?
Post by: RyanY on April 25, 2022, 10:31:41 am
I like to think it is HARD to break a well designed and tillered bow that is taken care of at a normal MC. Impressive result. Thanks for sharing!
Title: Re: max draw length?
Post by: superdav95 on April 25, 2022, 11:21:48 am
Cool test to the extreme.  Nice to know what the outer limits are.  That combo is a winner
Title: Re: max draw length?
Post by: BowEd on April 25, 2022, 01:25:41 pm
Impressive overdraw.Without pushing the limits a person never knows the boundaries and the quality of woods.
Long term regular usage is another.
Title: Re: max draw length?
Post by: WhistlingBadger on April 25, 2022, 05:54:45 pm
Wow, what fun!    :o   That bow deserves a spot in the "Takes A Lickin' and Keeps On Tickin' "  hall of fame.

But what kind of arrow speed are you getting from 104# @ 44"?   ;D ;D ;D

Title: Re: max draw length?
Post by: bownarra on April 26, 2022, 01:45:06 am
Fun test, i've done similar things with bows that didn't quite cut the mustard. Sometimes they can be drawn a long way sometimes not....
glass can easily do that :) and contrary to what you might think when glass fails it is pretty lame, just a slow fold.
Title: Re: max draw length?
Post by: simk on April 26, 2022, 03:32:37 am
really glad I've done this test: I now definitly know, my bows - in a normal operating range - are far away from being critical. Furthermore I'm absolutely amazed about this particular piece of yew - I never thought that it would tolerate such abuse without showing clear and visible signs of stress.
cheers