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Bamboo Backed Osage Warbow?

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cool_98_555:
I have just acquired a very good osage board at 1" thick and 72" long.  Grain is very good, with only 2 runoffs on the back.  Thinking of backing it with bamboo (strip is 1/4" thick).  For this warbow I want 100# @ 30".  Thinking of having handle area at 1.5" wide by 1.25" thick (bamboo backing included) and tapering out to .5" wide by .5" thick tips.  Is .5" thick enough to start tillering for 100#,  or should I start with .75 in thickness at tips?  Any other recommendations for width at handle are encouraged.  Thank you for your help!

Del the cat:
You would probably be fine with those dimensions for a boo backed laminate.
With a stave it's better to keep some extra width to allow you to move the nocks from side to side if necessary to stop any sideways bend/twist.
I normally rough out to 30mm square at the grip and 20 mm square at the tip. keeping the 30x30 for about 6" or so either side of centre and then taperinging out to the tips. I also go by the rough guide of 2mm thickness change every 6" along the limb.
Once it's flexing then it's down to eye and feel of course.
Roughing it out square gives some extra thickness and prevents you coming out light, and when I say 30x30 I mean that's where I draw the line, and I say outside of it, not on it.
The boo will need to be nice and flat on the gluing face and prob a bit thinner at the tips.
Hope that helps.
Oh, and glue it up with 1 or 2" of reflex, 'cos it'll pull a bit out when you tiller it.
Del

adb:
Your bow will end up 70" ntn once you cut the nocks on a 72" stave. That's ambitious for 100#@30". Certainly possible with bamboo/osage, but your tiller will have to be spot on throughout. I'd go with 1.25" wide, not 1.5", especially if you want a rounded belly.

Del the cat:

--- Quote from: adb on April 09, 2013, 05:20:37 pm ---Your bow will end up 70" ntn once you cut the nocks on a 72" stave. That's ambitious for 100#@30". Certainly possible with bamboo/osage, but your tiller will have to be spot on throughout. I'd go with 1.25" wide, not 1.5", especially if you want a rounded belly.

--- End quote ---
Why the heck would you lose 2" ???
If you do a horn nock correctly you can easilly just come down less than 1/2" at each end, even allowing a second groove for a stringer on the top nock.
If you are really careful you could probably get away with 71.5" ntn !
You can glue a block on the back of tips for temporary nocks during tillering.
Mind I agree that a bit more length would be nice.
Look at my Horn Nock Instructional ob myblog, you can see how close the gooves are to the tip.
http://bowyersdiary.blogspot.co.uk/search?q=horn+nock
Del

adb:
I usually lose 3/4" to 1" off each tip when I add overlays and cut the nocks.

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