Author Topic: New project  (Read 2040 times)

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Online DC

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New project
« on: March 15, 2019, 07:23:58 am »
New project :) :) Badgers comments about the advantages of a short working limb have intrigued me. I'm thinking about a sinewed, deflexed, static, recurved, molle with wide, short and thin working limbs. I'm a little unsure of the extemes. I have a piece of ERC sapwood that Wizardgoat gave me. It's 62"x 2 1/8" x 1". I'm thinking of splicing the statics on to extend it a bit as I'll lose 2 1/2" spicing in the deflex.
What I'm wondering about is the dimensions of the working limb. It will need some handle because there will be a splice. How long to make the limb compared to the levers? How thin is too thin? I'm after 40#@27". Do you think a 16-18" x 2" sinewed working limb would end up too thin? What are the problems with too thin?
Vancouver Island
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Online sleek

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Re: New project
« Reply #1 on: March 15, 2019, 08:02:35 am »
Thin is bad.  The limbs deform on release making energy transfer inefficient.  Thicker is quicker. I have built, and studied quite a bit on short bows and have made some decent ones. To get a thicker limb without increasing draw weight, you need to deflex the fade. I will write a bit about all this soon. I have about 3 typed pages of notes on this very subject that I have taken as I built them.
Tread softly and carry a bent stick.

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Offline Woodely

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Re: New project
« Reply #2 on: March 15, 2019, 10:36:42 am »
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.
"Doing bad work is an exercise in futility, but honestly making mistakes is trying your best."

Offline simk

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Re: New project
« Reply #3 on: March 15, 2019, 10:57:43 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.

Online sleek

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Re: New project
« Reply #4 on: March 15, 2019, 11:08:31 am »
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.

99 things can cause a bow to blow. To wide aint one.
Tread softly and carry a bent stick.

Dont seek your happiness through the approval of others

Online PatM

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Re: New project
« Reply #5 on: March 15, 2019, 11:10:08 am »
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.

Offline bradsmith2010

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Re: New project
« Reply #6 on: March 15, 2019, 02:00:17 pm »
yes,, I like wide limb bows,, if it fits the design,, Badger made a comment a while back ,, that he had made some wide limb bows and surprised at the mass weight being light,, something like that,, I like thin limb bows too,, just what ever works best for the wood and design,, ok I guess I like all bows,, (-S

Offline Woodely

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Re: New project
« Reply #7 on: March 15, 2019, 04:31:39 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.
"Doing bad work is an exercise in futility, but honestly making mistakes is trying your best."

Offline Badger

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Re: New project
« Reply #8 on: March 15, 2019, 04:55:20 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.

Offline SLIMBOB

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Re: New project
« Reply #9 on: March 15, 2019, 04:56:43 pm »
I’m not sure 1 5/8” at the fade qualifies as “wide” in my book. I would call that “not wide”. Somewhat “normal” even. So normal that I would bet most of the bows posted on this site are in fact wider than that. If you had argued that 4 inches wide posed a problem...might have had some takers. Even 3 inches. But at 1 5/8...you’ll have a hard time selling that that width is in anyway, anything other than...common. But I am curious to hear more on the overlapping grain...
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Offline Woodely

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Re: New project
« Reply #10 on: March 15, 2019, 05:15:59 pm »
  "curious to hear more on the overlapping grain..."     As I mentioned building laminate so its overlapping .    1 5/8"  is not wide  correct,   kind of like saying a 10' home ceiling is high, yes and no.
"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 #11 on: March 15, 2019, 05:18:57 pm »
I’m not sure 1 5/8” at the fade qualifies as “wide” in my book. I would call that “not wide”. Somewhat “normal” even. So normal that I would bet most of the bows posted on this site are in fact wider than that. If you had argued that 4 inches wide posed a problem...might have had some takers. Even 3 inches. But at 1 5/8...you’ll have a hard time selling that that width is in anyway, anything other than...common. But I am curious to hear more on the overlapping grain...

Kinda sounds like he had grain run out from back to belly rather than from side to side. Being a laminate, thats easy to do with a board.
Tread softly and carry a bent stick.

Dont seek your happiness through the approval of others

Online sleek

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Re: New project
« Reply #12 on: March 15, 2019, 05:22:07 pm »
  "curious to hear more on the overlapping grain..."     As I mentioned building laminate so its overlapping .    1 5/8"  is not wide  correct,   kind of like saying a 10' home ceiling is high, yes and no.

Maybe its not wide for a pine wood bow, or willow, or balsa. By not enough overlappimg grain, do you mean your backing strip was too thin? How thin was it? What woods are you using? How many have you made to base your conclusion on? Do you have any pics so we can better understand you?
Tread softly and carry a bent stick.

Dont seek your happiness through the approval of others

Offline SLIMBOB

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Re: New project
« Reply #13 on: March 15, 2019, 05:28:13 pm »
Maybe I misread. Didn’t you say that this one time only wide bow was 1 5/8” at the fades?  If not, I apologize. If you did, then you defined that as “wide”. I’m just trying to follow.
Liberty, In God We Trust, E Pluribus Unum.  Distinctly American Values.

Online DC

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Re: New project
« Reply #14 on: March 15, 2019, 05:32:40 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?
Vancouver Island
If you don't have any questions you must not be paying attention.