boo backed bamboo bow

[superdav95]

I narrowed up my tips to 3/8".   The forcedraw curve shown is out to 25" draw at 58.80lbs.  brace height from the back of the bow to the string is 6.5".   I measured the first 1/2" to 7" then every inch after that.   The question is do I keep going?  or do i call it where it is as i will not likely reach my target of 70lbs at 28".  It might be close.  if i go to 28" i figure around 65-67lbs???  let me know what you think.  the set back is holding pretty well so far.  only lost about a 1/4" right after unstringing. I suspect it will creep back most of the 1/4" through the day.  what think you fellers?

Link for pics
https://share.icloud.com/photos/0db0N--bglxf8wSy6NQY__AIw

[Robert Pougnier]

This is looking super snappy, I really like the profile it's keeping! Are you going to wait until the salt flats to do any full draw or shooting with it? It's looking awesome so far.

[superdav95]

This is looking super snappy, I really like the profile it's keeping! Are you going to wait until the salt flats to do any full draw or shooting with it? It's looking awesome so far.

Thanks Robert!  It feels snappy.  I’m gonna take this one as well as a few others out to a long field to distance check in the spring.  I’m Just putting the finishing touches on my flight arrows so will have something to shoot.  I’m also trying to decide whether or not I should continue with this bow or not as it will come short of my 70lb target.  More like 65-67ish.  Looking for input from other bow nerds to take a look at the draw curve and give me some direction on this one.  Not really sure what to do with it.  Option 1.  Reduce it down some to 50lbs at 26” like my self bow or option 2. Try to continue out to 29” draw and hope I’m close enough to 70lbs.  Option 3. Start over.   For all those reading and following should I try to take it to 29” and hope I don’t be way under 70lbs thus having to shoot a longer arrow also but it may be worth doing still???  Let me know what you think.   

[Robert Pougnier]

I've recently read something interesting, I don't know if it's relevant here and it sounds relatively risky anyhow:

Some flight archers shooting to break records will intentionally overdraw a lighter bow, say a 45# @ 28" drawn to 50# @ 30" (hypothetical numbers). Rather than shoot a bow that has been tillered to 50# @ 30# off the bat. I wish i could remember where i read this. It seems like a way to under build a bow on target for very dangerously low mass intentionally and squeeze the very most out of a flight bow. Maybe it also ensures compressive stress is kept to an absolute minimum prior to shooting.

Does this ring true or make sense?

[superdav95]

Robert what you describe is essentially what I may end up doing as option 2 for the 70lb class simple composite.  I’ll have to be prepared to build a long enough arrow to get as close to 70lbs.  This will mean a longer heavier arrow though but still may do well enough.  Thanks for the input. 

[sleek]

I've recently read something interesting, I don't know if it's relevant here and it sounds relatively risky anyhow:

Some flight archers shooting to break records will intentionally overdraw a lighter bow, say a 45# @ 28" drawn to 50# @ 30" (hypothetical numbers). Rather than shoot a bow that has been tillered to 50# @ 30# off the bat. I wish i could remember where i read this. It seems like a way to under build a bow on target for very dangerously low mass intentionally and squeeze the very most out of a flight bow. Maybe it also ensures compressive stress is kept to an absolute minimum prior to shooting.

Does this ring true or make sense?

Robert, thats 99% correct, at least to what I try to do when it all comes together. I will design a bow to pull 50@26, and tiller it out to be 44@24 and stop, never actually hitting 50 pounds ever on the scale. When it comes time to shoot the bow in flight, the ideal situation is the first time it ever hits 50 is at the weigh in, so its fresh. I make my arrow rest adjustable so that if its a little over and hits 50@25.5, I can move the rest to that position allowing my draw to be spot on.

[Selfbowman]

Dave if you have a shelf how are you going to keep the bow together at the handle attachment? I must not understand what I’m seeing in the photos.

[superdav95]

Ya Arvin the pics don’t show it clearly.  It’s glued to the wood handle and then wrapped with strong cord. Artificial sinew actually.  I’ll switch this up to flax cord later.  Similar to my other boo bow builds like the one you have it’s also got the relief ramp at the end of the handle on both ends.  I’ve got a 26” flight arrow to test out this bow to see how it does at 28” draw.  I’ll try to post more pics. 

[superdav95]

here are some better pics of the handle Arvin. 

on related note,  i may have a solution to reach my 70lb target.  the bow right now sits at 69"ntn.  I could move my overlays inward 1/2-3/4" or so on each side and it wouldnt mess with my tiller too much and add just enough draw weight.  I may try this in next couple days and see how it goes.  With some work the bow did balance out fairly nicley so this may be a good option for me without having to start over.

[superdav95]

Ok so I’ve popped off the horn overlays and moved them in an inch on both ends and reshaped them as before.  We shall see where we are as far as any increase tomorrow.  It’s now 67”ntn.  I did loose a little reflex height as a result.  It’s now just over 2”.  I’ll get some projected draw numbers and update.   

[sleek]

Be careful doing that. Moving the tips in changes the tiller shape, stressing the inner limb more.

[RyanY]

With such low set, I might have prioritized the shorter weight and draw length. Hopefully pushing it won’t stress it too much more. Looks really impressive.

[Badger]

  Dave somewhere you had mentioned shooting a fresh bow that had never been taken to full draw. I know of some real-world cases, and it is dramatic! I made an English longbow for Josef. He broke a world record with it at 450 yards. The bow had been tillered to 28", and on his first shot in practice, he drew it further than 28 and shot 530 yards. Another bow I had, I was working on a bow between rounds at the flight shoots. The bow I was working on was just a regular straight bow with about 1" reflex natural. Just for fun I decided to shoot it without ever having drawn it back before and I hit 387 yards. with a 50# bow. If you test this on a crono you will see how dramatic the results are. Build a simple shooting machine and use it with a scale in line that can hold the pondage reading. Tiller your bow out to about 24" tops and when you project it will hit 50# put it on the shooting machine. It is amazing how much we loose even on our best bows.

[superdav95]

Be careful doing that. Moving the tips in changes the tiller shape, stressing the inner limb more.

Ya I thought on it a while and came to the decision to try it.  I haven’t put a string on it yet to see how it’s changed it up.  My thinking was it was pretty long as it was at 69” ntn.  The sweeping tips seemed to have plenty of length yet when looking the profile.  Fingers crossed I guess.  Worst case I’ll just build another.  This one only took me a day to get glued up.   

[superdav95]

With such low set, I might have prioritized the shorter weight and draw length. Hopefully pushing it won’t stress it too much more. Looks really impressive.

Thanks Ryan.  I was originally thinking of just leaving it as it was.  Making the change to shorten it may be a mistake and put more stress past the tipping point.  I’ll see when I get it strung up to see for sure.  Nothing ventured nothing gained I suppose.