Sinew backed hickory

[bluejack]

I`m working on a shagbark hickory-64" ntn with recurved tips. Would like to try my first time with sinew backing- should I get to floor tiller stage or full tiller before backing or just go ahead and apply sinew before bending at all ? Thanks, Bluejack

[Pat B]

Bluejack, I usually get a bow bending well before adding the sinew. On some I've gone to about half tiller and others I've gone out to full draw before adding the sinew. You will probably have to make a few adjustments once the sinew cures out.
 I'm going to move this to "BOWS" so you will get more comments.

[bluejack]

OK- Thanks Pat-didn`t quite know where to post it.-Bluejack.

[superdav95]

I second what pat said.  I’ve done it also at the stage of just past brace and full tiller.  The last one I did had horn on the belly and so only tillered as far as brace height before applying sinew.  Otherwise I would get it bending really well then apply sinew like pat said.  Best of luck with your bow build. 

[bownarra]

Just to be different
I would advise against bending it too far. You should stop well short of getting any set. Ideally a sinewed bow should be reflexed quite a lot. Bellywood that has been compressed (significantly) does not like being bent backwards (whilst adding the reflex) and thus feeling tension.
Also a sinewed bow can easily become sluggish if the sinew isn't applied correctly. Sinew/glue matrix is dense stuff - about 1.3 s.g. - you have got to make it 'work' or else it is dead weight.
For me I would rough out the bow. Get it to brace height. Make sure the weight wasn't far to high. Heat treat the belly and reflex at the same time, about 2" reflex at this point.
Prepare and apply the first lay of sinew. Once the glue had gelled I would then reflex the bow further, about 4 - 5 inches total (with a reverse brace string). I would let that layer dry for 2 weeks. I would then sand the back, size with 5% gle and apply my 2nd layer. Again waiting until the glue gelled ten adding more reflex to about 6 - 7".
Leave to dry for two weeks then asses sinew thickness. Maybe add one more layer down the crown.
Leave it for a further 2 weeks.
Then tiller.

[bluejack]

Thanks guys, I would like to end up around 45# after sinewing-will I gain quite a bit of poundage from the sinew-if so- I should probably tiller to around what before adding sinew(40# ??)

[bradsmith2010]

Its pretty forgiving,, not bending it at all works, but tillering out some too works,,
maybe happy medium,, to brace,, see how that works for you,,

[Will B]

Great advice provided above!  Look forward to seeing this bow when completed

[bluejack]

Don`t worry Will B.-I`ll be asking you for help when the time comes!!

[gutpile]

sinew and hickory in the south is like oil and water.. they just don't mix however out west it can be a good combo. I always get my bow tilled to about 6 inch short of draw before sinewing.. lets the sinew work its magic more efficiently.. gut

[superdav95]

Thanks guys, I would like to end up around 45# after sinewing-will I gain quite a bit of poundage from the sinew-if so- I should probably tiller to around what before adding sinew(40# ??)

Bluejack.  If you go this route of tillering most the way prior to sinew application then you might have e better time hitting your target weight.  So many variables come into play.  I’m sure there are guys on here that have it narrowed down to thickness and ratios and such to get close but lots to consider.  On my last one I did I ended up adding about 10lbs draw for about 90grams of sinew.  I had low braced my bow for even bend with horn on the belly on this one first prior to sinew.  I also used homemade glue so that adds some variables.  Sorry to do this to you but you just gotta do it and see.  I used a ratio of 50% wood core to 25% horn and 25% sinew.  It worked out well with this combo.  If you are just doing sinew and wood anywhere from 80-100 grams is what I’ve heard tell guys using and get good results.  Bownarra and bowed both gave me some great advise for my build I’m sure they will help you along when you get going.   Best of luck on your build. 

[gutpile]

I wouldn't assume 10lbs of draw weight.. I would just till like no sinew is being added .. if you gain 10 great just shave some off till you hit weight.. you will have to retill after sinew anyway.. easier to take off then try to add on with more sinew.. one thing I do is hang a 25lb weight from handle suspended in between two chairs.. the sinew will pull in some reflex but this way assures it..gut

[bluejack]

Thanks for all the replies- great place for info!! bluejack :-