Stack help please :)

[Buemaker]

I would like to have it.

[Mad Max]

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

[Mad Max]

This may work too
http://www.mediafire.com/file/ckul4wdru1oq97o/Stack_Calculator.xls/file

[Buemaker]

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

[Mad Max]

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

 

[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

[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]

.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.

[Mad Max]

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

[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.

[Longcruise]

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.

[Mad Max]

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

[Arlo]

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]

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]

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

     

[Longcruise]

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. 

[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.