Primitive Archer

Thanks Guys, got surgery next Tuesday, he said it was kind of a mess with tears/arthritis and some old stuff from the pasted I didn't even know about  but he felt pretty good about fixing it, so we will see. Had a good weekend and had a great time visiting with Rocky and Frits, them guys are a hoot.  Got a few things done around the shop but we were mostly in wood cutting mode and got a bunch done. I was tractor man most of the time but did use the saw when my buddies weren't watching me.  Shaw showed up and got all his billets and stave sealed and ready for the barn. Lot of good wood in a year or 2.
 Pappy

Quote from: superdav95 on February 22, 2026, 12:51:30 am

I read through some of that’s stuff on sinew and chew vs hide glue.  The twisted sinew cable bow is also very cool.

knowing you are an experimental and questioning kind of guy, I would ask....

do you have any ideas about how much sinew should stretch in order to add the most benifit?

or asked another way, how high or far away from the belly is optimal?

Great question.  Preamble… I make these statements and claims purely based on my own experiences.  FWIW. 

BowEd and myself have discussed this topic together quite a bit.   How much sinew??? A general rule a thumb has been and continues to be 1/3 overall thickness in the case of a tri lam of sorts for the lack of a better term.  1/3 sinew thickness: 1/3 wood core: 1/3 horn for example.  This ratio works really well for a belly laminated bow with horn having wood as the core.  In other examples that are just 2 laminated sections like wood core only with sinew then this would depend on how heavy you want your bow to be I suppose.  Like any sturdy backing added to an existing bow it moves the neutral plane further towards the belly.  The neutral plane is generally in the middle of the bow limb but this can be manipulated with laminate backings or sinew or linen even on the back.  The same can be true with adding a belly laminate that acts as an increase in compression to move this neutral plane more towards the back.  Tension side failures are easy to spot and are often hard to miss with a lift or a violent break.  Compression is where the set is less obvious in the same way that tension failures are.  They can sneak up on us and show up as stress marks and crushed wood fibers.  Sinew added to a bow with no belly laminate I generally aim for 1/8” thickness.  This obviously varies a bit depending on the width of the limbs and where along the limb I’m measuring.  For example I will taper the thickness of sinew out towards the tips to keep mass light in those areas of the bow for better cast.  I’ll thicken it up on bending portions.  For reference the little Osage 48” bendy bow recurve I just sinewed last week I only added 50grams.  This may seem like very little sinew and may seem like it will make no difference perhaps.  My draw weight prior to sinew was 48lbs at 26”.  My goal and likely outcome with strategically placing sinew with the least amount of glue as safely as I can hopefully get 55-60lbs at 28” safely.  So the little added mass added with the sinew I estimate will get me there.  If this was a bow with a violated back or decrowned for example then 50grams would not be enough imo.   In the case of an already well tilled and shooting bow that the builder has maintained good build principles and not violated the outer ring then less is more to a point.  If the builder is merely looking for extra draw length with a margin of extra safety then it’s a good option.  I’ve built self bows in the past and backed with heavy layers of sinew and glue only to find it was slower then before.  Stability is another issue that gets overlooked.  I built a bow for a member here with out mentioning him by name where the bow had more sinew then the core would could control.  This particular bow build was a white wood bow and the target draw weight was too high or over estimated so I proceeded to scrape the belly to reduce weight.  In so doing the wood was about half the overall thickness of the bow with the sinew and the wood could not control it and became unstable.  Constantly needed correction and tweaking for balancing the limbs.  I then decided to add a thin belly lam of horn and it turned out great and moved that neutral plane where it was more stable.  So my advise to anyone wishing to add sinew to an already well behaved shooting bow that they just want a little more out of as far as weight and length of draw aim for approx 1/3 of overall thickness for a standard 1-1/2-1-3/4” wide limb out the fades.  On some wide limbed paddle bows or the like really the same sort of principle applies but it’s gets tricky to determine on some of those as far as thickness is concerned as there often more tapers and narrowing sections where no sinew may be needed at all.  For these measured bundles of wide strips of sinew bundles I find work well on the working part of the limbs.  As a rule of thumb on a hunting bow for example say 45-50lbs of standard flat bow or pyramid style 1/8” thickness of dried sinew layer is a good baseline.  The great thing about sinew is that if you screw it up you can always redo it sand it scrape it or add another layer to get it right.  You can’t really do this with any other backing.  So to sum up,  an all sinew bow doesn’t work for a reason because it’s not stable so putting the neutral plain somewhere within the wood portion of the limb is best for stability and balance.  The sinew will enhance the wood adding to it.    These are my opinions from my own experiences and experiments (so called)and from the input of many others along the way.  I learned from Ed and others like Arvin here the importance of taking measurements and keeping notes to assist with the best build.  I hope this somewhat answers your question Willie!   

Yes heavy bows are not pleasant to build

No never heard back from him after I sent it to him

Fantastic build! I hate building heavy bows! I can’t pull them back, strain myself stringing them and not knowing where to start on tiller. I have some draw weights written on my tillering board for a hundred pound long bow from one I’ve made but still not a lot of fun.

I talked about such a bow about 10 years ago http://www.primitivearcher.com/smf/index.php/topic,54972.msg746709.html#msg746709. At the time I wasn't interested in making it but I did get around to building one, after the guy couldn't find anyone to make it for him, but never got around to posting pictures.  There is no full draw image but here are a couple pictures





The bow was 150# @ 30" and made out HHB backed with Maple.  It was a "crazy" build and not something I would recommend.  The string tension at brace was nuts.  Here is a picture as I was tillering it drawn to 29"