Author Topic: How much sinew?  (Read 3365 times)

0 Members and 1 Guest are viewing this topic.

Offline Blaflair2

  • Member
  • Posts: 2,042
How much sinew?
« on: December 16, 2013, 10:53:10 am »
How much sinew do I need to back a 52" bow? I'm talking deer leg sinew. I have 4 so far
Nothing ventured nothing gained

Offline osage outlaw

  • Member
  • Posts: 11,962
Re: How much sinew?
« Reply #1 on: December 16, 2013, 12:11:09 pm »
It will take more than that.  If you can't get any more shoot me a PM.  I have some I would trade.
I started out with nothin' and I still got most of it left

Offline wood_bandit 99

  • Member
  • Posts: 197
  • Shoot straight my friends!!   55#@26"
Re: How much sinew?
« Reply #2 on: December 16, 2013, 12:22:43 pm »
I have heard it takes 16 legs
"Judge a man by his questions, not his answers" ~Anonymous

   "The person who says it cannot be done should not interrupt the person who is doing it." ~Chinese Proverb

Offline PEARL DRUMS

  • Member
  • Posts: 14,079
  • }}}--CK-->
Re: How much sinew?
« Reply #3 on: December 16, 2013, 04:41:00 pm »
About 10-12 decent length back strap sinews will give you a solid 3 courses.
Only when the last tree has died and the last river has been poisoned and the last fish has been caught will we realize we cannot eat money.

Offline PatM

  • Member
  • Posts: 6,737
Re: How much sinew?
« Reply #4 on: December 16, 2013, 04:54:51 pm »
A lot depends on your ability to shred the sinew and what your ratio of waste is per tendon.

Offline Blaflair2

  • Member
  • Posts: 2,042
Re: How much sinew?
« Reply #5 on: December 16, 2013, 09:13:22 pm »
I don't have enough. I'm working on getting more. And I don't have squat to trade ATM. Thanks for the offer. 

I've never done it so ill probly say my ratio sux
Nothing ventured nothing gained

Offline Pat B

  • Administrator
  • Member
  • Posts: 37,633
Re: How much sinew?
« Reply #6 on: December 16, 2013, 09:18:55 pm »
You'll want more on hand than you'll actually need just incase.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline osage outlaw

  • Member
  • Posts: 11,962
Re: How much sinew?
« Reply #7 on: December 16, 2013, 10:35:58 pm »
Are you in the lower 48?  If so I'll send you some pieces. 
I started out with nothin' and I still got most of it left

Offline Blaflair2

  • Member
  • Posts: 2,042
Re: How much sinew?
« Reply #8 on: December 16, 2013, 10:45:50 pm »
Yeah I'm in NY. A lot of my buddies didn't get many deer this year
Nothing ventured nothing gained

Offline osage outlaw

  • Member
  • Posts: 11,962
Re: How much sinew?
« Reply #9 on: December 16, 2013, 10:54:09 pm »
Send me a PM with your address.  They might not be the longest pieces you've ever seen but they will definitely work.
I started out with nothin' and I still got most of it left

Offline Marc St Louis

  • Administrator
  • Member
  • Posts: 7,877
  • Keep it flexible
    • Marc's Bows and Arrows
Re: How much sinew?
« Reply #10 on: December 17, 2013, 08:42:27 am »
I have done 4 courses with as little as 8 tendons with a bit left over.  It's all in how you apply it
Home of heat-treating, Corbeil, On.  Canada

Marc@Ironwoodbowyer.com

Offline Danzn Bar

  • Member
  • Posts: 4,166
Re: How much sinew?
« Reply #11 on: December 17, 2013, 08:01:25 pm »
Marc,
When you say courses are you describing layers of thickness??  Please help me with the terminology. and I guess you apply it very thin also.
DBar
Integrity is doing the right thing when no one is looking

Offline Marc St Louis

  • Administrator
  • Member
  • Posts: 7,877
  • Keep it flexible
    • Marc's Bows and Arrows
Re: How much sinew?
« Reply #12 on: December 19, 2013, 09:40:34 am »
When we say courses it means layers.  Most people apply sinew over the entire limb but I do not.  Many years ago I did some thinking on the subject matter and I deduced that it was not necessary to apply sinew that way.  What I started doing was to apply the sinew to maximize it's use plus keep the added mass as low as possible.  I figured that a limb does most of its tension work down the center where you have a crown and that the outer parts of a bows limbs do very little work.  I knew that sinew is more elastic than wood so it could stand to have a high crown.  What I therefore did was to apply no more than 1 course along the edge and the outer limbs.  Then moving were 2 courses progressing to 4 courses down the center of the limb.  This produced a higher crown, almost like a cable of sinew down the center of the limb.  All of the bows I sinew backed were short, highly reflexed static recurves and they all shot into the 180 fps with 10 GPP arrows using dacron strings.  I'm sure that with FF strings and a bit of tweaking of the design it would have been easy to shoot 190+.  Jeez, just talking about it makes me want to make one  :)
Home of heat-treating, Corbeil, On.  Canada

Marc@Ironwoodbowyer.com

Offline Eric Garza

  • Member
  • Posts: 589
Re: How much sinew?
« Reply #13 on: December 19, 2013, 05:31:51 pm »
For the last several years I've been doing it the same as Marc, lay down a ribbon of sinew down the center of the limb so that it creates a crown and focuses all of the tension on the sinew rather than the wood. Usually this ribbon of sinew is only 1/2 inch wide or so. If I'm worried that a splinter might raise as the wood bends, I'll put a layer of the thinnest rawhide I can get over the whole bow's back once the sinew's cured for a few months. I've found this approach offers me the best trade-off between the benefits of sinew (higher elasticity, holds down splinters) and the drawbacks (tedious work involved in shredding and applying it as a backing, higher weight-to-strength ratio).
« Last Edit: December 20, 2013, 03:08:38 pm by Eric »

Offline Danzn Bar

  • Member
  • Posts: 4,166
Re: How much sinew?
« Reply #14 on: December 19, 2013, 06:12:30 pm »
Thanks Marc and Eric,
I have been researching this a lot and have come to the conclusion that more layers /courses or thicker sinew in the middle of the bow is best.  Thanks to Osage Outlaw I have enough sinew to build my first sinew back bow this winter.  I'm going to start this weekend.
Thanks again for the info.
DBar
Integrity is doing the right thing when no one is looking