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Main Boards => The Bowyer's Bench => Topic started by: LittleBen on October 31, 2014, 11:38:00 AM
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So I've been thinking about two things ...
The first is that I don't think I'm gluing enough reflex into my tri-lams, and the second is that I want a really short (say 52"-54") recurve for hunting.
So my questions are these:
1)how much reflex are you guys gluing into your bows? Specifically tri-lams but any backed bows really. I've been gluing from 2-4" of reflex and the bows usually take around 3" or so of set, so I end with very slight reflex or slight string follow. I'm thinking of going to like 6-8" of reflex ... anyone have experience with this? Going to need to cut a new form I think.
2) Anyone who's built/has pics of a nice short reflexed/deflexed and or recurved wood bow, please post it so I can start planning my next move. Lookign for some inspiration.
3) has anyone ever sinew backed a tri-lam bow? I have one that has a failing backing (white oak ... never again) and I'm thinking of stringing it backwards and putting a super clean, and relatively thin sinew backing onto it and trying to simultaneously fix the backing, gain alot of reflex, and gain some draw weight.
Thanks!
And for what it's worth, I'll be building it as a hickory backed ipe tri-lam almost undoubtedly. Only other possibility is osage belly instead.
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This is a sinew backed osage recurve I built last year. She is 56"t/t, 56#@26", and has 3 courses of cow sinew on the back...
(http://i5.photobucket.com/albums/y199/PatBNC/LilThumper005_zps56eb3d46.jpg) (http://s5.photobucket.com/user/PatBNC/media/LilThumper005_zps56eb3d46.jpg.html)
I added about 3" of backset when I added the sinew but most of it worked out during tillering and shooting in...
(http://i5.photobucket.com/albums/y199/PatBNC/LilThumper001_zpsf5f29176.jpg) (http://s5.photobucket.com/user/PatBNC/media/LilThumper001_zpsf5f29176.jpg.html)
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Top: 44" with serious deflex and recurves
Bottom: 48" Scythian with setback handle and serious recurves
(http://i21.photobucket.com/albums/b282/kenhulme/TwoBows_zps5bf772f5.jpg) (http://s21.photobucket.com/user/kenhulme/media/TwoBows_zps5bf772f5.jpg.html)
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Are you talking about just a wood bow?
6-8 inches of reflex with a wood bow is a waste of time. You will just end up with more set.
What you really want for a wooden bow to be as fast as possible is fresh belly wood....not belly wood that has been forced to bend too far. Personally the most reflex i'd ever start tillering with would be around 4 inches and aim to keep 2 1/2 - 3 inches.
Remember also that reflex is great but it doesn't make for a stable bow.
I think your best bet is to make a reflex/deflex recurve. This design has allowed me to go short, maintain unstrung reflex AND get a stable, great shooting bow. My best did 207 fps at 8 gpp from a super clean black locust stave.
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Yes I'm talking all wood, as per my usual.
I've been building almost exclusively deflex reflex and deflex recurve tri-lam bows for the last year and I'm just trying to get some better performance out of them. They shoot great, but with a 25" draw length I need something with more speed.
The trilam seems to lose reflex more easily than a simple backed bow or selfbow. I've been gluing 3-4" of reflex. That leaves maybe 2.5-3" once it's off the form, and typically slight reflex after tillering. And yes, obviously more reflex will cause more set, but I'll just widen the limb slightly or something if it doesn't net some reflex.
Would love to see the black locust. 207fps is very fast. Are we talking like on shot number one, or is that after a break in period?
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Wider and thinner will return slower than narrow/thicker limb. Think of a tuning fork :)
For a 25 inch draw length i'd be going as narrow as possible and follow the mass principle set out in TBB4.
My locust bow is still shooting more or less at that speed maybe just a little slower 5 fps or so. I've since made 5 more bows in this design and they have all shot great. Not quite the same speed but very close. I've used osage, elm and more locust on these bows.
So from what you are saying I would be trying to limit the set the bow is taking during tillering. Keep thinking fresh bellywood, fresh bellywood!
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Originally posted by mikkekeswick:
Are you talking about just a wood bow?
6-8 inches of reflex with a wood bow is a waste of time. You will just end up with more set.
What you really want for a wooden bow to be as fast as possible is fresh belly wood....not belly wood that has been forced to bend too far. Personally the most reflex i'd ever start tillering with would be around 4 inches and aim to keep 2 1/2 - 3 inches.
Remember also that reflex is great but it doesn't make for a stable bow.
I think your best bet is to make a reflex/deflex recurve. This design has allowed me to go short, maintain unstrung reflex AND get a stable, great shooting bow. My best did 207 fps at 8 gpp from a super clean black locust stave.
Remember also that reflex is great but it doesn't make for a stable bow.
Just a question
Describe a unstable bow to me?
Thanks
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Would love to see a pic of your locust bow Mike!
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I'll try and get one taken. It's nothing special to look at really it's all in getting to full draw without the bellywood breaking down that's key.
Mark _ the point I was trying to make is that a bow that is simply reflexed will be more twitchy and less forgiving than a bow with say an inch of string follow.
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Hi Ben,
I'm no great bowyer..may be the worst on here...lol
One time I tried an all wood tri longbow with a LOT of curves...
(http://i748.photobucket.com/albums/xx121/Zradix/Tri%20lam%201/CIMG0001.jpg)
I broke it early in tillering.
Maybe someone much better than I could've got this done..
Now I realize this was a LB and you're thinking recurve.
The problem I ran into was getting the tips to come around so when braced the string wasn't touching 1/2 way down the limb.
With a glass backed bow I could've made the limbs bend more close to the riser than anywhere else and been ok.
With the all wood and trying to keep things bending evenly throughout the limb ...I was kinda screwed...lol
Just food for thought...
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If your losing 3" or so from its starting position in a laminate bow then your doing something wrong..I.e poor tillering or design,or both....most I've ever lost is near 1 1/2",and most of them lose an inch at most or less regardless of how much reflex I've started with. Even if you have a proven great design,it won't do well if you don't do your part right in tillering. Its not about the end result bend,but everything you do before you get there.
Depending on the type of lam bow I'm making I generally glue in 1-5" of reflex. Anymore isn't worth it.
I wouldn't waste time sinewing a trilam,or trying to save an old one...pointless IMO.
Zradix your shape is not optimal,and is what caused your issue. The apex of your reflex is in the inner mid limbs...that can cause some serious instability, and other issues. In short you want the apex of your reflex out near the tips...you want it to increase as you get closer to the tips.
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Black Mockingbird - Agreed 100%
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Interesting thoughts all around.
It seems like the main thing I need to be looking at is why I'm getting alot of set. Seems that 3" or so should be plenty of reflex if I can keep the set down as mentioned.
I think I'm going to just really slow down on the tillering process and make sure it's perfect before drawing further. See how that works out.
Overall I've been pretty happy with the way my tri-lams shoot but every bit helps.