Author Topic: Deflex Angle?  (Read 4752 times)

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Offline Arrowind

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Deflex Angle?
« on: February 04, 2015, 10:11:21 pm »
I've been building more and more R/D bows.  (trying to anyway)  :laugh:

Does anyone have a suggestion for ideal angle for deflex coming out of the handle?  If I glue two billets together at the handle at a slight angle down to create deflex or bend the handle with steam is there some kind of optimum angle?  Just curious if anyone has thoughts on this.  Normally I just eyeball that kind of stuff but I'm interested in knowing if anyone has actually done some research and has come up with an ideal or optimum angle....

Talking trees. What do trees have to talk about, hmm... except the consistency of squirrel droppings?

Offline bubby

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Re: Deflex Angle?
« Reply #1 on: February 04, 2015, 10:16:13 pm »
A year or so ago Mark st Louis had a build a long in pa that i have saved for a future build
failure is an option, everyone fails, it's how you handle it that matters.
The few the proud the 27🏹

Offline Arrowind

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Re: Deflex Angle?
« Reply #2 on: February 04, 2015, 10:40:54 pm »
Cool.   Did he mention anything about deflex angle?
Talking trees. What do trees have to talk about, hmm... except the consistency of squirrel droppings?

Offline bubby

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Re: Deflex Angle?
« Reply #3 on: February 04, 2015, 11:18:28 pm »
Sure did, off the top of my head i cant remember the issue I'll see if i can find it
failure is an option, everyone fails, it's how you handle it that matters.
The few the proud the 27🏹

Offline Blaflair2

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Re: Deflex Angle?
« Reply #4 on: February 04, 2015, 11:55:46 pm »
I plan on making a jig and using saw kerfs in a similar way. I was thinking of 15 degrees for each half, equaling around 30 degrees
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Offline steve b.

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Re: Deflex Angle?
« Reply #5 on: February 05, 2015, 01:21:47 am »
30 sounds about right.  It depends on what the limbs will be doing and what the length of the bow will be.  I'm starting a bow soon using a 1" wide electrical conduit corner for a handle.  I'll cut the corner down so that it is about 5" long and that will make the radius about 30 degrees.  Then I'll glue reflexed oceanspray billets in.  I'll heat reflex them some more then make a bow.  Just depends on how much deflex you want/need.

Offline Badger

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Re: Deflex Angle?
« Reply #6 on: February 05, 2015, 01:47:40 am »
  I don't know the angle but mine drops to the depth of the handle at about midlimb.

Offline Will H

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Re: Deflex Angle?
« Reply #7 on: February 05, 2015, 08:47:28 am »
I've built my fair share of RD bows. I've never really measured deflex by angle. The angle is relative to how long or short the bow you are making. So I've always measured deflex (and reflex for that matter) relative to the back of the handle. My personal opinion on the matter is that with selfbows, too much deflex is a bad thing. Less is more as they say. My favorite is about an inch of deflex at midlimb and 2-3" of reflex.
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Offline Del the cat

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    • Derek Hutchison Native Wood Self Bows
Re: Deflex Angle?
« Reply #8 on: February 05, 2015, 10:22:38 am »
I've just made one... I went for about 15 degrees. I did it by gut feel first, then checked on the interweb, and many risers seem to have 15 degrees.
Dunno if this bow will be any good, but is sure pretty  :-* >:D
http://bowyersdiary.blogspot.co.uk/2015/02/hazel-flight-bow-nearly-there.html
BTW. if you measure along 4 and up 1 it gives you 14 degrees, (e.g tangent of 14 degrees is V near 0.25) which is a reasonable approximation and nice and easy. Mind I still managed to screw up the drawings of my riser at least 3 times >:(
Del
« Last Edit: February 05, 2015, 10:36:50 am by Del the cat »
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Offline Arrowind

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Re: Deflex Angle?
« Reply #9 on: February 05, 2015, 09:44:56 pm »
Thanks for all the insight guys.  It seems like I remember hearing 15 degrees once before now that it's mentioned here.  As I mentioned I've just been trying to eyeball it so I'm really not sure.  I've been curious about how much is toooo much and how much is just right.

Dell that looks really cool.  I'd like to know how that one turns out.  I'm thinking of going for something like that with recurves. 

Bubby - yeah I'm thinking of something like the kind of bows  Marc St Louis  makes.   it seems that gluing two limbs at the handle might give you more control over the amount of deflex or just be a little easier to get the desired angle.  Never tried it before.  just thinking of trying it.

When you did that take down bow a while back did you eye it or did you actually go for a specific angle.  Just curious.  that's a cool bow.  I'm thinking of trying something similar in the near future.

Will H  I like your approach.  Just so I understand are you measuring deflex at midlimb - the back of the limb is 1" lower that the back of the handle?  Then 2-3" reflex..like   The back of the tips are 2-3" higher than the back of the handle?   ???

   
Talking trees. What do trees have to talk about, hmm... except the consistency of squirrel droppings?

Offline Arrowind

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Re: Deflex Angle?
« Reply #10 on: February 05, 2015, 09:46:26 pm »
Hey Dell,

I just checked your site again and realized you've already done some shooting.   Any updates?
Talking trees. What do trees have to talk about, hmm... except the consistency of squirrel droppings?

Offline bubby

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Re: Deflex Angle?
« Reply #11 on: February 05, 2015, 10:10:27 pm »
I just eye balled it, sometimes for me it's easier to just wing it
failure is an option, everyone fails, it's how you handle it that matters.
The few the proud the 27🏹

Offline Arrowind

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Re: Deflex Angle?
« Reply #12 on: February 06, 2015, 12:09:39 am »
I just eye balled it, sometimes for me it's easier to just wing it


Yeah, I hear you on that.  That's what I usually do.  I like winging it more than following some kind of complex recipe.  I enjoy that (winging it) more but this question has gotten stuck in my mind as I'm trying to understand deflex a little more.  Thanks for your help on this.
Talking trees. What do trees have to talk about, hmm... except the consistency of squirrel droppings?

Offline Del the cat

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    • Derek Hutchison Native Wood Self Bows
Re: Deflex Angle?
« Reply #13 on: February 06, 2015, 03:06:21 am »
Hey Dell,

I just checked your site again and realized you've already done some shooting.   Any updates?
Nah, just shot half a dozen arrows... but today I might get her finished and shot through the chrono.
I'll post it on here when it's all finished.
I'm not sure it will be that fast as Hazel prob' isn't favourite for a flight bow, but that's half the fun :laugh:
Del
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Offline Springbuck

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Re: Deflex Angle?
« Reply #14 on: February 06, 2015, 04:21:07 pm »
  When I was a noob, and making a bunch of lam bows, I started using less and less deflex.  At first it just seemed obvious to get as much as you can of reflex, and take advantage or Perry principle, etc.

  What I found was that wrestling the limbs back counter acted the Perry results a bit, and that a gentler R/D worked better if well executed.

  Anyway for self bows, I generally don't deflex anything.    I don't like having to put a lot of deflex in the limb itself, off the handle, since it is harder to actually deflex the handle itself.  Some of the guys have already posted ways around that, though.

 If I am working with a naturally deflexed stave, what I do is even up the deflex, and then either recurve or reflex from there.  I get the limbs moving on the long string a bit, then boil and bend recurves, then overlay or heat treat.   OR I reflex the whole limb over a form with heat, and it makes a natural R/D.  I like these enough that I am actually always on the lookout for sapling back splits, or other staves that will give me a nice, even, deflex.