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Stack help please :)

Started by bownarra, January 19, 2022, 04:51:01 AM

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Buemaker


Mad Max

Quote from: Buemaker on January 19, 2022, 04:59:02 PM
I would like to have it.

I sent it to you
Let me know if it works Bue

I'm not a big computer nerd so I don't know if it will work :pray:
I would rather fail at something above my means, than to succeed at something  beneath my means  
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Mad Max

I would rather fail at something above my means, than to succeed at something  beneath my means  
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Buemaker

Thank you Max. Will see tomorrow if I can load it up to Exel.

Mad Max

I would rather fail at something above my means, than to succeed at something  beneath my means  
}}}}===============>>

Noah70

I think all I have to do is copy it and send it to a email, and you open in Excel ?

If possible, could you please send that to me?  I'd like to see how it compares, if my iPad will open it.. its supposed to I think.
Thanks!
Noah

Any man who lives within his means clearly lacks imagination

Jeff Freeman

My phone opened it but I only got the lower half on an Excel graph sheet. I can't read anything on the top to slightly left of what I got. JF
🦌🏹😃

Longcruise

Quote from: Jeff Freeman on January 19, 2022, 02:35:31 PM
.440 is what I used and it will end up 45# I'm almost there now.
Mine was just a guess going off my records from previous longbows built. JF

Changing limb width is linear.  IOW, a limb 2" wide and 50# would be reduced to 25# if the limb were reduced to 1".

As regards limb thickness,  the changes in thickness effect draw weight with a factor of eight. 

I have two stack calculators and they both function based on that math. They aren't perfect but they are very very close.

For the type of bows that you mostly build, as do I,  the Bingham chart is very close but you have to remember that it's based on the width of the Bingham design.  But, it's very easy to use the linear aspect of the width formula to calculate weight.
"Every man is the creature of the age in which he lives;  very few are able to raise themselves above the ideas of the time"     Voltaire

Mad Max

Quote from: Noah70 on January 19, 2022, 06:03:03 PM
I think all I have to do is copy it and send it to a email, and you open in Excel ?

If possible, could you please send that to me?  I'd like to see how it compares, if my iPad will open it.. its supposed to I think.
Thanks!
Noah


Reply #22 has a link
I would rather fail at something above my means, than to succeed at something  beneath my means  
}}}}===============>>

Crooked Stic

For these things to work you have to have a bow already built and know its stack. Everything the same except the stack. I have found that if the desired weight is is a bunch more say 20 lbs. you might be off some.
High on Archery.

Longcruise

Quote from: Crooked Stic on January 19, 2022, 07:10:21 PM
For these things to work you have to have a bow already built and know its stack. Everything the same except the stack. I have found that if the desired weight is is a bunch more say 20 lbs. you might be off some.

I found the same.   Using 1# for every 003 seems to be pretty much the same.
"Every man is the creature of the age in which he lives;  very few are able to raise themselves above the ideas of the time"     Voltaire

Mad Max

Quote from: Noah70 on January 19, 2022, 06:03:03 PM
I think all I have to do is copy it and send it to a email, and you open in Excel ?

If possible, could you please send that to me?  I'd like to see how it compares, if my iPad will open it.. its supposed to I think.
Thanks!
Noah

Lets see if the copy for Bue works
I would rather fail at something above my means, than to succeed at something  beneath my means  
}}}}===============>>

Arlo

Quote from: Mad Max on January 19, 2022, 09:16:26 AM


That's a good calculator but..... that other good data info on the bottom is bogus.
Lengthening a riser with the same limbs will decrease the draw weight, not increase it.

Jeff Freeman

Ok so how does the calculator work. Need to show your work, to come up with the boom. JF
🦌🏹😃

mmattockx

Quote from: Jeff Freeman on January 21, 2022, 11:18:04 AM
Ok so how does the calculator work. Need to show your work, to come up with the boom. JF

Bending stiffness of a rectangular section beam of a homogeneous material is proportional to the thickness cubed. The calculator uses that to calculate the new stack height. It isn't strictly accurate because the fibreglass lams carry much more of the load than the core material, but it is close enough to accurately predict small changes in weight.


Mark

Mad Max

Quote from: Jeff Freeman on January 21, 2022, 11:18:04 AM
Ok so how does the calculator work. Need to show your work, to come up with the boom. JF

Weight increase %      =(C9-C8)/C8
Target Stack increase   =-(1-(POWER(1+C10,1/3)))
Target Stack Thickness   =C7*(1+C11)  Boom

     
I would rather fail at something above my means, than to succeed at something  beneath my means  
}}}}===============>>

Longcruise

Quote from: Mad Max on January 21, 2022, 03:33:08 PM
Quote from: Jeff Freeman on January 21, 2022, 11:18:04 AM
Ok so how does the calculator work. Need to show your work, to come up with the boom. JF

Weight increase %      =(C9-C8)/C8
Target Stack increase   =-(1-(POWER(1+C10,1/3)))
Target Stack Thickness   =C7*(1+C11)  Boom

     

Phew.  Finally someone simplified it.  :biglaugh:
"Every man is the creature of the age in which he lives;  very few are able to raise themselves above the ideas of the time"     Voltaire

Jeff Freeman

Oh yeah now I get it 🤣🤓 much easier to understand
🦌🏹😃

bownarra

Bow came out right on inteneded weight. One veneer moved so had to narrow it a mm or two more than I would've wanted but hey....I've still hit weight and she has pretty limb edges now haha...
Osage and Honduras Rosewood - not too shabby.

Buemaker

I was able to move it to Exel and could plot in the numbers I wanted, but I can't make it calculate. I have to find someone who knows this stuff.

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