Author Topic: Longbow limb twist  (Read 1815 times)

0 Members and 1 Guest are viewing this topic.

Offline Iskelton

  • Member
  • Posts: 11
Longbow limb twist
« on: September 19, 2021, 01:40:07 pm »
Hi all, I’m new to bow making and to this site and I have a very (basic?) question about limb twist, why is it bad? Can it cause damage to the bow it’s self and cause it to fail or is it more of a performance driven issue? I know if limb twist is bad enough it can cause the string to slip off of the nocks but that’s about all I know. Also how much limb twist can one get away with? Thanks a bunch!

Offline Woody roberts

  • Member
  • Posts: 179
Re: Longbow limb twist
« Reply #1 on: September 19, 2021, 02:40:08 pm »
I’m looking forward to what the pros have to say. Most of my bows have a little twist somewhere. If they shoot ok l generally don’t mess with it.
Same with warps or bends. I draw a line up the center of the tree and layout off of that. If the string favors one side of the handle that’s the side I shoot off of.
I don’t know if what I do is correct but it works for me.

Offline simson

  • Member
  • Posts: 2,310
  • stonehill-primitive-bows
    • stonehill-primitive-bows
Re: Longbow limb twist
« Reply #2 on: September 20, 2021, 01:21:54 pm »
A little twist (<30°) isn't a problem,  or maybe an aestethetic.
More should be heated out, see my buildalong if you aren't sure.

Your stick: What wood? How much twist? What design?
Simon
Bavaria, Germany

Offline Pat B

  • Administrator
  • Member
  • Posts: 37,618
Re: Longbow limb twist
« Reply #3 on: September 20, 2021, 05:48:17 pm »
Also depends whether the twist is in the stave or happens as you draw the bow. Like Simon said a little twist is OK with a selfbow. All wood laminated bows might be different, more like glass bows.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline GlisGlis

  • Member
  • Posts: 1,561
Re: Longbow limb twist
« Reply #4 on: September 22, 2021, 05:25:09 am »
I also guess that a twist is much more a problem in a flatbow (wide and thin) than in a rounder shape (oval) as you will have to cut more into fibers where twist occur while tillering.

Offline Del the cat

  • Member
  • Posts: 8,322
    • Derek Hutchison Native Wood Self Bows
Re: Longbow limb twist
« Reply #5 on: September 22, 2021, 08:07:48 am »
My go-to field bow is called twister... I could have taken the twist out, but I enjoyed the challenge of tillering it to draw true despite the twist.
With narrow bows like an ELB, it can lead to a sideways bend which is bad. I saw a bloke shooting a Yew ELB that had bent/twisted so much that the sapwood was no longer on the back it was at about 45 degrees to the back of the bow... mind TBF, it still shot!  :o
Del
Health warning, these posts may contain traces of nut.

Offline hoosierf

  • Member
  • Posts: 492
Re: Longbow limb twist
« Reply #6 on: September 22, 2021, 11:54:08 am »
My experience is similar to Dell’s photos.  Saplings often twist in opposite directions and seem to shoot pretty well when you tweak them so the string crosses the handle near the grip.   It can give you a center shot effect. 

Offline Iskelton

  • Member
  • Posts: 11
Re: Longbow limb twist
« Reply #7 on: September 28, 2021, 01:22:47 am »
My go-to field bow is called twister... I could have taken the twist out, but I enjoyed the challenge of tillering it to draw true despite the twist.
With narrow bows like an ELB, it can lead to a sideways bend which is bad. I saw a bloke shooting a Yew ELB that had bent/twisted so much that the sapwood was no longer on the back it was at about 45 degrees to the back of the bow... mind TBF, it still shot!  :o
Del

Thanks so much for your reply! That is a very nice bow! Thank you for sharing. My stave is pacific yew wood with quite a lot of twist in her. I’ll post some pictures. I’m interested in whether or not I should take the twist out.


Offline Iskelton

  • Member
  • Posts: 11
Re: Longbow limb twist
« Reply #8 on: September 28, 2021, 01:25:09 am »
A little twist (<30°) isn't a problem,  or maybe an aestethetic.
More should be heated out, see my buildalong if you aren't sure.

Your stick: What wood? How much twist? What design?

Thanks for your reply Simson! I’m using pacific yew, and a simple pyramid flat bow design I’m pretty sure. I’ll post some pictures! Im looking forward to know what you think!

Offline Iskelton

  • Member
  • Posts: 11
Re: Longbow limb twist
« Reply #9 on: September 28, 2021, 01:33:15 am »
here are the photos of the stave! 

Offline simson

  • Member
  • Posts: 2,310
  • stonehill-primitive-bows
    • stonehill-primitive-bows
Re: Longbow limb twist
« Reply #10 on: September 28, 2021, 03:22:06 am »
That twist isn't that big, you can go with it.
I personally would heat it out, it is very simple. You need a caul, a weight and a heat gun.
How to proceed (esp. to get the torsion force against the twist) look to my post: http://www.primitivearcher.com/smf/index.php/topic,70432.0.html
Simon
Bavaria, Germany