Author Topic: board opinions for pyramid bow  (Read 8095 times)

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Offline Twokag

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board opinions for pyramid bow
« on: May 02, 2013, 03:30:38 pm »
I want to make a pyramid bow for my daughter, she is 5'10" and athletic build.  I am starting with a 2.5" x72" red oak board.  My plan is to cut it to 68" with a 10" riser.  Tips at 1/2".

Does that sound like a reasonable starting point?
What would the anticipated draw be at around 27"?
do the image of the boards give any concern for grain?

thanks
Scott

Offline bubby

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Re: board opinions for pyramid bow
« Reply #1 on: May 02, 2013, 03:39:06 pm »
thius will help, mind that you don't have to use a tablesaw but these dimensions will workhttp://www.primitivearcher.com/smf/index.php/topic,35312.0.html
failure is an option, everyone fails, it's how you handle it that matters.
The few the proud the 27🏹

Offline dragonman

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Re: board opinions for pyramid bow
« Reply #2 on: May 02, 2013, 04:37:49 pm »
to me, the board looks good and the dimensions sound right.....
'expansion and compression'.. the secret of life is to balance these two opposing forces.......

Offline DarkSoul

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Re: board opinions for pyramid bow
« Reply #3 on: May 03, 2013, 06:27:29 am »
The grain of the board looks good. Not perfect, but without a backing it should be ok.
How old is your daughter? The drawweight and drawlength will depend on that. The drawweight will determine the width of the bow, while the drawlength will determine the length of the bow. The dimensions you've listed so far sound fine, though.
"Sonuit contento nervus ab arcu."
Ovid, Metamorphoses VI-286

Offline Twokag

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Re: board opinions for pyramid bow
« Reply #4 on: May 03, 2013, 04:53:06 pm »
Thank you for the link.
I plan to rough it with a band saw, and then use a table top sander to clean it up, then hand tools to finish it.

My Daughter is 19, and 5'10" tall.  She is not her to measure her draw length. I was going to make it so I could pull it, and her draw will be shorter than mine so she will be able to shoot it. I would guess she will be 26-27".  I am making it as a birthday present, so I don't want to call and ask her to measure.




Offline bubby

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Re: board opinions for pyramid bow
« Reply #5 on: May 03, 2013, 05:21:24 pm »
I think she will draw closer to 25"-26", good luck with the build, post pics and ask ?
failure is an option, everyone fails, it's how you handle it that matters.
The few the proud the 27🏹

Offline DarkSoul

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Re: board opinions for pyramid bow
« Reply #6 on: May 03, 2013, 05:59:20 pm »
I think 35# at 27" would be a pretty good guess. I'd personally cut it to 70" nock to nock, since you're looking for an unbacked bow and a stiff handle. I'm sure 68" can be done, but 70" gives you a bit more leeway since you don't know her drawlength for sure.
"Sonuit contento nervus ab arcu."
Ovid, Metamorphoses VI-286

Offline Twokag

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Re: board opinions for pyramid bow
« Reply #7 on: May 10, 2013, 11:17:17 am »
I have had feedback suggesting from 66"-70" so I split the difference and went with the 68".  2.5" at the handle. just about 1/2" thickness.

The shape has been cut, and the thickness roughed in.  One limb I have smoothed the belly and the edges, the other not yet.  I need to tune the band saw to get a cleaner line next time.

Mostly the bow will be for backyard fun, no hunting, no distance or accuracy competition.  As long as it is usable for her, the finished weight is less important.

My question now if for the handle.  I left plenty of wood to work with.   I have read about fades and handle width, etc.  From the images below, what would you suggest I do next?   I am open to making the handle shorter if needed.

Thanks for the help.
« Last Edit: May 10, 2013, 11:40:41 am by Twokag »

Offline autologus

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Re: board opinions for pyramid bow
« Reply #8 on: May 10, 2013, 11:32:53 am »
If you made the bow 40# at 28" it would probably come in just right for her.  If she is 5' 10" and athletic she should be able to handle that weight with out much trouble especially after she has shot it some to get those muscle groups strengthening.

Grady
Proud Hillbilly from Arkansas.

Offline Peacebow_Coos

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Re: board opinions for pyramid bow
« Reply #9 on: May 10, 2013, 04:29:03 pm »
I'm not sure what those lines going on the diagonal are about, but if those are your fade lines you might wanna re-think that! :)  For a young girl the handle might be best skinny(1 1/8" to 1 1/4" wide) and deep as you got it.  Depends on the shape you want, I've put a slight groove in the belly side of the handle where the web of the thumb/forefinger rides and that seems to be agreeable, but I'd take some width off for sure.  Not sure how much will make it bendy, you'll have to wait for the heavy hitters to chime in.  Good project man, hope it works out :)

Offline bubby

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Re: board opinions for pyramid bow
« Reply #10 on: May 10, 2013, 04:58:38 pm »
it really depends on how it is tillered, next time try and stay a little farther away from the line with the saw, buy the time you get that all evened out it may come in super light
failure is an option, everyone fails, it's how you handle it that matters.
The few the proud the 27🏹

Offline dragonman

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Re: board opinions for pyramid bow
« Reply #11 on: May 10, 2013, 05:33:54 pm »
I agree with Bubby on that....keep those machines well away from your line ....
'expansion and compression'.. the secret of life is to balance these two opposing forces.......

Offline JW_Halverson

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Re: board opinions for pyramid bow
« Reply #12 on: May 10, 2013, 06:19:59 pm »
Depending on her form, she might pull up to 30", especially if her arms are long.  40 lbs would be a nice bow for all day shooting and still be able to throw a light target arrow with good speed.  The Pyramid shape lends itself to shooting light arrows while minimizing handshock.  I bet you can even narrow the limb tips more without getting into danger. 

Love to see it at full draw when she gets it.  Wonder what will be the nicer arc...the bow or the smile on her face?
Guns have triggers. Bicycles have wheels. Trees and bows have wooden limbs.

Offline Twokag

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Re: board opinions for pyramid bow
« Reply #13 on: May 10, 2013, 06:47:44 pm »
The smile will be bigger, I hope. 

The pencil lines don't mean anything at the moment for the handle, just playing and did not erase.

I have the limbs right at 1/2", and I got my transition from the handle to limb cleaner.  I agree, keeping away from the lines will be needed next time.

I am not sure of the shape of the handle. the width of about an inch and keeping it full depth of 1.5, or close to that. where do I start narrowing the width to come down to 1"

the images below, looks like one of the fades (correct term?) is a little different angle than the other, does that matter?

Offline k-hat

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Re: board opinions for pyramid bow
« Reply #14 on: May 10, 2013, 07:25:46 pm »
Lately i've been doing my grips like this:  for 8" handle/fade area i have the center at about 1.25" wide narrowing in both directions to 1" wide (this is where the fades begin), then widening to full limb width at the ends of the fades.  Hope that makes sense!  You may also try drawing your lines on the back instead of belly (or in addition to) since it's nice and flat.