Author Topic: design for an oak bow  (Read 8114 times)

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Offline dragonman

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design for an oak bow
« on: January 02, 2009, 01:42:56 pm »
I've noticed several red oak bows on this forum that look pretty good. In the uk. people don't consider oak a bow wood so it is suprising. Does anyone know how redoak compares to white oak? and I'm wondering how american white oak compares to english?, I'm guessing it's pretty similar???
I've never really put much time into self bows, but I'm now inspired to become more primitive and oak trees grow everywhere round here, practically the most common tree in this area.
What desiign specifications would people suggest for an unbacked oak bow? the unbroken growth ring theory has always put me off in the past, untill I saw the west coast replica, redoak flat bow posted last week. great looking bow, wouldn't have thought it possible.
'expansion and compression'.. the secret of life is to balance these two opposing forces.......

Offline Kegan

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Re: design for an oak bow
« Reply #1 on: January 02, 2009, 06:32:26 pm »
Red oak has a SG of .55 to .65- meaning it's a good wood. If the piece is light, you might want to leave the draw weight lower, but other than that- go for it. It's  little less tough than white oak, but dries more quickly and splits more cleanly. I actually prefer it a bit myself. I don't know how it compares to English oaks, but here the wood's excellent- I don't see why it would be very different.

Red oak makes great flatbows and D bows, but I've had toruble making it into ELB's- don't take belly tempering the same as white oak, elm, or hickory.

Offline shamus

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Re: design for an oak bow
« Reply #2 on: January 02, 2009, 08:41:09 pm »
White oak is a decent bow wood.  I made my wife white oak bow: http://analogperiphery.blogspot.com/2008/05/m-shoots-her-first-selfbow.html.


Quote
The unbroken growth ring theory has always put me off in the past,

Not sure what you mean. Peel off the bark and inner bark, and you'll have the bow's back ready. For a hunting weight bow, I'd design a flatbow, 1.75 wide or so and taper to it to 1/2" at the nocks. I prefer a pyramid type of width taper on flatbows. Or you can make a D bow. I that case, 1.5" wide is the widest you would go.  Those are just two basic options.

more thoughts of mine on bow design: http://analogperiphery.blogspot.com/2008/05/osage-flat-bow-dimensions.html .

Yes, it's about osage, but the principles can be applied to other woods. I hope it helps.
« Last Edit: January 03, 2009, 11:21:14 am by shamus »

CutNShoot

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Re: design for an oak bow
« Reply #3 on: January 02, 2009, 10:25:22 pm »
19/32 to 7/16 will make one  in the 55 category, with a lot of scraping. Good oak up to 70.  I think you have to take almost and 1/8 off of that to get to 50. I'm talkin flat bow now. ;D. Just did a red oak board and I was tryin to make it just under 50 and it ended up 55 @ 26 for shooting in to 28. Its 69" knock to knock 8" non bending handle. we will see.

CutNShoot

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Re: design for an oak bow
« Reply #4 on: January 02, 2009, 11:02:41 pm »
Oh I forgot to say 1 1/2 " wide at the fades full width all the way to within 14 to 16 inches from the tips then tapering in to 1/2" knocks at the very tip. (Thickness) 19/32 to 7/16 6 inches from the tips to where it starts getting thicker to the tips, then 7/16 to 9/16 thicker to the tips. Last 6 inches went back up to like 9/16 like the new age Holmies for lace of a better term.  Sorta super stiff non bending tips. I think the Straight slant pyramid is probably the fastest design. Holmies rock though and if done right are super fast. They look funny tillerd but are really fast. I would drop the thickness by 16 all the way for a 2 Inch pyramid, but have never built one.

Offline dragonman

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Re: design for an oak bow
« Reply #5 on: January 04, 2009, 11:02:49 am »
thanks, cutnshoot and  shamus, that is helpfull info i appreciate it
'expansion and compression'.. the secret of life is to balance these two opposing forces.......

CutNShoot

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Re: design for an oak bow
« Reply #6 on: January 04, 2009, 12:33:57 pm »
The kind of red oak I have been getting puts to much strain on the back if you start out at 3/4 to a 1/2 inch at the tips thickness straight taper unless you scrape about an 1/8 inch off that, just to much removal for a knife scraper. LOL! I have a rasp but you have to be careful not to take off to much too. I think the most prevalent mistake I have made is trying it get it braced to soon. If you've never built one or have one at your hand for comparing it's hard to know how much floor tiller is right. They really need to bend more than I thought anyway. If you string em up to soon/to heavy then they will take more set. I use a long string to start out that is tight the full length of the bow so there is no slack in it.Then I keep tightening it as I go on each scrape session or 2 Don't know if that is right or wrong but it works for me and as soon as I can I get it on the string and that is when the tips are moving about 7 to 8 inches. Once I get it strung to first brace it usually at about 5 inches brace and if all is right even I pull it to the intended draw weight and keep pullin it there till I'm out to the length I want or I here that dreaded rifle sound. I finally got smarter and looked at the draw curves in the trad bowyers bible to get an idea of where I should be on weight as I progressed in length to keep from starting out to heavy ;D. If it blows please don't blame me this is just the way I do it. ;D

Offline dragonman

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Re: design for an oak bow
« Reply #7 on: January 04, 2009, 12:55:23 pm »
sounds like a good method to me, pretty much how I do it.  I can only get white oak though, do you think it will work the same?
'expansion and compression'.. the secret of life is to balance these two opposing forces.......

CutNShoot

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Re: design for an oak bow
« Reply #8 on: January 04, 2009, 04:03:54 pm »
Don't really know heard White oak is stronger and tougher.Also may be a reason not to switch in my 02 but it should work. I know I went 19/32 at the fades and tapered out and I'm still scrappin wood off to get it below 50. I finally got it down to where when you scrape it,it changes weight. LOL! Instead of 20 scrapes a side for 1/16 travel.

Offline ozarkcherrybow

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Re: design for an oak bow
« Reply #9 on: January 04, 2009, 04:24:25 pm »
I prefer red oak over white. All of them that I have made has taken less set than white oak. Around here it is easy to find perfectly straight trees to make into staves.  The best bow that I have ever made was a red oak, 72 inches, 72# @28".  I boiled the tips and gave them a little recurve look to them.  Sold that bow when someone insisted on buying it from me, but I wish I did'nt sell it.
I believe that the width was 1 7/8 at the fades  out to just past mid limb and tapered to 1/2 at the nocks. That is usually the layout I use on all my oak bows.......Terry
any stick do for bow, but good arrows are damn heap work

Offline dragonman

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Re: design for an oak bow
« Reply #10 on: January 05, 2009, 07:09:48 pm »
thanks guys , that is usefull
'expansion and compression'.. the secret of life is to balance these two opposing forces.......

Offline broad_head

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Re: design for an oak bow
« Reply #11 on: January 06, 2009, 09:41:05 am »
Dragonman
                 In my experience I have found that American white oak has much straighter grain than the English variety. I have seen a number of small saplings that looked quite straight down here in Kent but I have never tried it, lots of ash?
            Peter (UK)