Author Topic: New project  (Read 2045 times)

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Online sleek

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Re: New project
« Reply #15 on: March 15, 2019, 05:36:39 pm »
  The comments I made about short working areas on the limb can be easily confused. When I can get away with short working areas I dod but in most cases I need most of the limb working to avoid set. I usually leave the last 8 or 10" pretty stiff and I like longer fades like 3" or even a bit more only if I can get away with it and not take too much set. Avoiding set is my #1 priority.
I agree with you on set being number one. Wouldn't a wider thinner limb be under less stress and take less set?
Yes, but there are diminishing returns in form of mass, and limb deformation on release. Limbs get rubbery as they get thin.
Tread softly and carry a bent stick.

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Offline PatM

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Re: New project
« Reply #16 on: March 15, 2019, 06:12:23 pm »
I have only ever built one wide bow.  I think it was 1 5/8" wide at the fades.  The wood was perfect, I was barely 10 minutes into tillering and exercising it when it blew up on the tiller stick.  Won't build another wide limb bow again, all my laminate bows end up at around 1 7/16" to 1 3/8" wide.

 Surely you don't think that was the cause.

I do as a matter of fact,  it was to thin and not enough overlapping grain .   I think that wide and thin can have a negligible effect on the woods stress limits.

 You mean the wood was NOT perfect then.   Also negligible means it has virtually no effect.  You must mean negative.

Offline bradsmith2010

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Re: New project
« Reply #17 on: March 16, 2019, 06:12:31 am »
sleek,,,couldn't u just make the limb shorter,,to compensate for mass,,

Offline DC

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Re: New project
« Reply #18 on: March 16, 2019, 06:20:43 am »
DC, for comparison, I do my moelles with 13:17 bend/lever ratio. The bending limb is 1 7/8" wide at the fade, is 38 cm long and has maybe 12-15 mm in thickness.
Where did you come up with 13:17 ;D ;D Is it some kind of Fibonacci sequence?
Vancouver Island
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Offline Woodely

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Re: New project
« Reply #19 on: March 16, 2019, 06:27:17 am »
  The comments I made about short working areas on the limb can be easily confused. When I can get away with short working areas I dod but in most cases I need most of the limb working to avoid set. I usually leave the last 8 or 10" pretty stiff and I like longer fades like 3" or even a bit more only if I can get away with it and not take too much set. Avoiding set is my #1 priority.

I agree with Badger on that one.

=======================================================
"You mean the wood was NOT perfect then.   Also negligible means it has virtually no effect.  You must mean negative."

Must of got up from the wrong side of the bed that day.  I would have to take that statement back and wipe it out as it does make sense as you pointed out.  At any rate it was long ago when I built such a bow, all I remember is I dont like the looks feel or tillering such a beast and will stick with bows in the 1 7/16" width or there abouts.  I like to have more meat in the thickness department to work with.  :)  When I'm tillering tapering and trapping are the last things I do to get the tiller I'am trying to achieve.
« Last Edit: March 16, 2019, 06:44:06 am by Woodely »
"Doing bad work is an exercise in futility, but honestly making mistakes is trying your best."

Online sleek

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Re: New project
« Reply #20 on: March 16, 2019, 07:01:39 am »
sleek,,,couldn't u just make the limb shorter,,to compensate for mass,,

Yes, and by natural progression of design, a thin limbed bow WILL be a short bow.
Tread softly and carry a bent stick.

Dont seek your happiness through the approval of others

Online SLIMBOB

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Re: New project
« Reply #21 on: March 16, 2019, 07:17:05 am »
So, 1 7/16 wide is ideal. 1 5/8 is a beast. Thatís a pretty small difference between the two extremes. That sure doesnít leave much wiggle room. Are you sure you didnít just mistate your point?  That would be understandable. I once said on here that back sinew wasnít used for backing bows. Turns out I didnít use it for that, but many people did. I was just wrong. No harm in being wrong. Remaining that way, a different story.
Liberty, In God We Trust, E Pluribus Unum.  Distinctly American Values.

Offline Badger

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Re: New project
« Reply #22 on: March 16, 2019, 07:47:51 am »
  The comments I made about short working areas on the limb can be easily confused. When I can get away with short working areas I dod but in most cases I need most of the limb working to avoid set. I usually leave the last 8 or 10" pretty stiff and I like longer fades like 3" or even a bit more only if I can get away with it and not take too much set. Avoiding set is my #1 priority.
I agree with you on set being number one. Wouldn't a wider thinner limb be under less stress and take less set?

  Yes, the less working limb I am shooting for the wider I go in the working areas.

Offline Woodely

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Re: New project
« Reply #23 on: March 16, 2019, 09:16:01 am »
So, 1 7/16 wide is ideal. 1 5/8 is a beast. Thatís a pretty small difference between the two extremes. That sure doesnít leave much wiggle room. Are you sure you didnít just mistate your point?  That would be understandable. I once said on here that back sinew wasnít used for backing bows. Turns out I didnít use it for that, but many people did. I was just wrong. No harm in being wrong. Remaining that way, a different story.

Tongues get twisted as do typos,  ok maybe 1 13/16"  is a beast.  At any rate did not know this Forum was so stuck on particulars  and Rocket science wizardry.     ;D
"Doing bad work is an exercise in futility, but honestly making mistakes is trying your best."

Online sleek

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Re: New project
« Reply #24 on: March 16, 2019, 09:40:22 am »
So, 1 7/16 wide is ideal. 1 5/8 is a beast. Thatís a pretty small difference between the two extremes. That sure doesnít leave much wiggle room. Are you sure you didnít just mistate your point?  That would be understandable. I once said on here that back sinew wasnít used for backing bows. Turns out I didnít use it for that, but many people did. I was just wrong. No harm in being wrong. Remaining that way, a different story.

Tongues get twisted as do typos,  ok maybe 1 13/16"  is a beast.  At any rate did not know this Forum was so stuck on particulars  and Rocket science wizardry.     ;D

Well yeah, thats just how magic works man...
Tread softly and carry a bent stick.

Dont seek your happiness through the approval of others

Offline bradsmith2010

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Re: New project
« Reply #25 on: March 16, 2019, 10:04:10 am »
rocket science wizadry,,,, I like that,, )P(

Offline DC

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Re: New project
« Reply #26 on: March 16, 2019, 10:17:38 am »
OK the project will continue on but with a change that put's some limits on. I was cleaning up under my bandsaw and found a piece of yew that is 23" long. With a finger joint splice in the handle being 2 1/2" and the 3" "V" for the lever that leaves me about 14" working limb. Pretty short but the Yew was on it's way to the fire pit so I'll save Goats ERC piece for something else. If this breaks, well it will have used up a couple of week of shop time and I won't have to find room for "another bow" ;D ;D Using Simks formula that means about 17" lever, that will be about a 62" bow.
Vancouver Island
If you don't have any questions you must not be paying attention.

Offline maitus

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Re: New project
« Reply #27 on: March 16, 2019, 10:29:01 am »
Everything about limbs is very well described in Adam Karpowicz book. General rules for hornbow limb dimensions work as well for wooden bows. Suggest to read :).  After reading this book, i got 171 f/s out of elm selfbow with 32 grams arrow.
« Last Edit: March 16, 2019, 11:58:52 am by maitus »

Offline DC

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Re: New project
« Reply #28 on: March 16, 2019, 03:41:36 pm »
I wish I could find a printed copy, not fond of Ipads.

Some pictures of the days work. Cutting the glue up apart and splicing the handle. Picture of my finger joint jig. I cut down on the deflex from my usual 11į to about 9į Had company so I didn't get much done.
Vancouver Island
If you don't have any questions you must not be paying attention.

Offline DC

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Re: New project
« Reply #29 on: March 17, 2019, 04:53:57 pm »
Today I fit the recurves "V" joints and glued on a "power lam" which is just a splice reinforcement. Flattened the belly of the handle and made a cover for the belly side of the splice. Then I glued it all up. I'm thinking I will use a Maple backing rather than sinew. I can get Maple and have a limited amount of sinew. I'll save the sinew for the ERC I was originally going to use for this.
Vancouver Island
If you don't have any questions you must not be paying attention.