Width of red oak d bow

[UrsusNil]

Hello, I'm working on a red oak board bow, the goal is a working handle d profile. 65" tip to tip, 26" draw, 40 lbs. Right now the mid section is 1.5" wide tapering to .5" nocks. The specs are from a bow in the Bowyers Bible. I'd like to reduce the width a bit, I'm thinking to about 1.25" at the mid section. Am I pushing my luck? Would backing the bow help? Thanks for your help!

[takefive]

All my bows have a rigid handle and I know that even 1 1/2" would be narrower than what I'd want to start with using red oak.  Maybe you can pull it off with a bendy handle.  Have you been on Jawge's site?  He has a follow along for a bendy red oak bow.  Good luck on your bow!

  http://georgeandjoni.home.comcast.net/~georgeandjoni/boardbowbuildalong.html

[Pat B]

You could make the limbs 1 1/2" wide but neck down the handle area to 1 1/4".

[aus-archer]

I would say that's to thin for red oak, but then again give it a shot if it breaks start again. I've made a couple of nice shooters with similar dimensions at 45-50# and 71" ntn.

With good straight grain on the back and a dense board, heat treat some reflex and then heat treat again after tillering, those dimensions might work better. The problem with 1.5" limb width and a d back tapering to .5 is the strain on the belly making it crystal, A flat limb section spreads that compression strain over a greater area, as the red oak is weak in compression. Heat treating with increase it's compression strength some, but it's still nothing like yew or osage.

Give it a shot see what happens. Breaking bows and experimenting on boards is part of the experience.

[mikkekeswick]

I think he means d-bow as in the way it bends not the profile ofthe belly.
What a lot of people overlook with red oak is that it's tension strength is much better than it's compression resistance. One thing that will make a huge difference is to trap the back by a good amount, like making the back 30% narrower than the belly. I can't stress how important this is  
Your 1 1/4 width will be fine once you sort out the woods naturally different properties - tension v. compression. The set that people normally associate red oak with won't appear!
PatB - I've had bows break when you narrow just the handle section for comfort on bendy handle designs. Even with a very gradual taper.

[KenH]

I agree with Mike.  Nothing wrong with 1.25" width tapering out to .5".  Also agree that trapping the back is important in this case.  The belly will be 1.25 and the back just over 1.0 at the midpoint, and carry that angle out to the ends.

The only backing you want is something light to prevent splinter rise -- silk ribbon, brown paper tape, that sort of thing.

I have a red oak bow of almost exactly those proportions, only 50" tip-to-tip.

[George Tsoukalas]

Thanks, takefive.
If you rip the board to 1 3/8" you have a better chance of getting 45-50#.
I  don't usually trap or back red oak.
Remember straight grained stock is needed.
Jawge

[UrsusNil]

Very interesting, didn't think about trapping it. Well, back to the bench....

[John Scifres]

40# at 26", 65" bend in the handle...1-1/4" wide will work.  Expect 2" of set.

I would not back red oak.

[mikkekeswick]

Virtually no wood needs backing IF the grain is plumb straight but as we all know those boards are rare  
I think Ken was meaning if the grain was at all wavy.
Jawge - If done quite a few tests with tension strong woods like red oak/ash/hickory etc. I have made short d bows, pyramid limb taper (ease of tillering) and have pulled them until they have taken a lot of set. Then taken the bow to the bandsaw and cut them along the neutral plane. What happens? The belly bends into MORE set and the back goes back to almost straight. This tells me that the back isn't doing it's fair share of 'work' compared to the belly. Often the bows belly has taken an extra two inches or so of set once cut free from the back....the results have really surprised me. I think it was a chap on PP that worked out red oak backs can safely be reduced in width to about 60% of the belly width and still be safe.

[George Tsoukalas]

Mike, trapping is good. I just never bothered. Jawge

[horsebackhunter]

Thanks mikkekeswick, you just explained a lot, I've been trying to make a hunting weight bow for awhile now and my daughter has a lot of bows and theres lots of kindling for the stove. Ash mostly. With what I just learned about heat treating and what you explained here, I think I can get one done by fall.

[LittleBen]

Red oak seems to vary ALOT in density, some really dense boards I wouldn't hesitate to narrow (there's a good example in TBB of a narrow red oak longbow of 70# 71" and 1.5" wide IIRC). It's hard to say much of anything without seeing and feeling the piece of wood with red oak.

Personally I think you can probably  make 40# @26" and 1.25" wide with average density boards .... But only one way to find out.

Forgot to add .... I think Mikekeswick is right on with the trapping. I believe it is a highly underused approach, I hear a lot about making "thin" backing strips to prevent chrysals but really trapping is the mathematically best approach.