Is there a formula ?

[Stick Bender]

After killing and digging under a bunch of wasps I ended up with a clean short 44 in. stave I was planing on making a retro flip parallel limb bow with 5 in. of combined reflex I didn't want to tiller this bow beyond brace so I'm figuring to bring it to about 30 lb.  draw weight at brace and adding the reflex plus 900 grains of elk sinew so I'm figuring that should ruffly give me about 60 lb. brace weight but that's just a guess on my part I was wondering if there is any formula for figuring estimated brace weight ? 

[Stick Bender]

Bugs

[gfugal]

dang that's unfortunate.

[osage outlaw]

I hate borers 

[Badger]

 Brace weeight is always exactly zero. Do you mean at 1" draw? or pulling a long string so the limbs move the same distance they would if braced?  The pounds pulled on a long string mean nothing unless you are also looking at how many iches your string is pulled to, not limb movement. You naturally want the sting as short as possible maybe hanging loose a few inches. I have never has sinew add that much weight, I would think about 10# or so but I have never really measured it.

[Stick Bender]

OO that was only stave I put in my shop a year ago figuring it would be to cold for them to live over winter I was wrong and it will be the last brought in with bark on that are nasty horid critters that I enjoy mercilessly killing but that stave was always going to be a short draw bow so didnt lose a thing 

[osage outlaw]

OO that was only stave I put in my shop a year ago figuring it would be to cold for them to live over winter I was wrong and it will be the last brought in with bark on that are nasty horid critters that I enjoy mercilessly killing but that stave was always going to be a short draw bow so didnt lose a thing 

A few years ago at the Classic I pulled a borer worm out of a stave I was working on.  I toasted it over the fire and ate it.  Seemed like a just punishment for eating my bow wood.

[Stick Bender]

Steve I mean once I get it to brace un reflexed if I where to pull on the braced bow with 30 lb presure thats what it would take to move the string I was factoring in the additional 5 in of reflex over all with the same method just basing my guess on a short hickory bow I made after reflexing it picked up a lot more steam then I imagined so I figured 5 in of reflex 15-20 lb  & 10-14 lb with sinew but like I said just guessing ?

[upstatenybowyer]

OO that was only stave I put in my shop a year ago figuring it would be to cold for them to live over winter I was wrong and it will be the last brought in with bark on that are nasty horid critters that I enjoy mercilessly killing but that stave was always going to be a short draw bow so didnt lose a thing 

A few years ago at the Classic I pulled a borer worm out of a stave I was working on.  I toasted it over the fire and ate it.  Seemed like a just punishment for eating my bow wood.

You should have video taped that. You could play it over and over on a loop in front of your wood so maybe those little $%#$er's will think twice before digging in to your stash! 

[Danzn Bar]

OO that was only stave I put in my shop a year ago figuring it would be to cold for them to live over winter I was wrong and it will be the last brought in with bark on that are nasty horid critters that I enjoy mercilessly killing but that stave was always going to be a short draw bow so didnt lose a thing 

A few years ago at the Classic I pulled a borer worm out of a stave I was working on.  I toasted it over the fire and ate it.  Seemed like a just punishment for eating my bow wood.

You should have video taped that. You could play it over and over on a loop in front of your wood so maybe those little $%#$er's will think twice before digging in to your stash! 

There were a few pictures taken but no video.......
DBar

[BowEd]

Ritch...Draw length of 22"?Don't really know of any formula.I would tiller it to 12" to 14" at 20 to 25 pounds.Flip your tips.Brace it again.Align tips if need be.Remeasure the draw weight at 12" to 14".Tiller it back to previous draw weight.Sinew it up with your 900 grains.Reverse bracing it as you go.
With 900 grains on there I'm not sure what percentage of thickness compared to your wood thickness you'd have though.The sinew will be all of 2 to 3 mm or at least 1/8" thick.
Just my 2 cents.That would be my shot at it.I've never made one though.Others on here I'm sure could tell you for sure though.

[bradsmith2010]

I am not quite sure of the brace at 30 question,,
when I brace the bow for the first time with sinew on it, It feels a bit heavy to get it strung,, cause I know the sinew is gonna stretch and i want some room to tiller,, so I string it heavier than a self bow,,
using a not stretch string helps with this on the refexed ones,,

for exampe,, one time I was making a bow and did not want to overstrain it at first brace,, so I would hang the long string on a bucket that weighed 45#,, and see how far the limbs would move, I would just leave the bucket on the long string for an hour sometimes trying to get the sinew to stretch,,

well I got the bow to bend about even with 45 of weight on long string,,,, it would pull  the reflex out at that point,,

the bow was looking small,, so I thought maybe I better string this thing,,,,, I did,, once braced the sinew stretched,, and I was barley getting 45 at full draw of 29 inches,,,,

I dont have a formula, but I string it when it feels like about 70# bow the first brace, ,that gives me room for the sinew to stretch and some tillering,, to even it out,,

that is why alot of times people miss the weight on a sinew bow, the sinew stretch is tricky to judge,,

[Pat B]

I prefer to tiller a bow to be sinewed to at least 1/2 the ultimate draw length and estimate from there what the poundage at full draw; about 3# per inch of draw. When the sinew is cured I retiller out to full draw at the weight I desire.

[Stick Bender]

Thanks guys  for the thoughts ,in the one in this pic I pretty much built it as Ed & Pat recommended ,tillered it to a little over half draw the stave had a few issues so I went a little lighter it's starting to sag the string good at 6 1/4 in. reflex two weeks cure  time, Brad thats why I was trying to keep it heavy to brace I had missed my target weight before on a hickory/sinew bow, on this current one Im half thinking of leaving the limbs strait & pin knocking to gain maximin working limb but not sure if the string would stay put at 22 in. Brad you would have a better handle on that then most ? Figured I would post here so others can learn Too , there is somthing intriguing about these short draw bows to me , it would be amazing to take a primitive kill with one !

[bradsmith2010]

thats looking really nice,, I am sure when  :-Dyou tiller it, its gonna shoot great,