How to measure the bow length

[V-Archer]

Hi all,

The other day a guy from another shooting club and I were discussing how to measure the bow length from nock to nock. He says that you take a measuring tape at one nock (N) at the belly side and then in a straight line to the other nock (N) following the curves at the limb ends. This is the dashed line in  picture A.
I have learned to follow the curves from nock to nock and that's the bow length. This is the dashed line in picture B
Also he claimed that the required string length should be the bow length, as measured in A, minus 3 inches, where as I say the bow length, as measured in B, minus 4 inches.
Let's hear what you guys say.

V-Archer    

 

[vermonster13]

If you want to be at AMO standards you can find all your answers here.

 http://archerysearch.com/publications/AmoStandards.pdf

[va]

i read the link and did not find a description of measuring Bow Length.  Did I nod off in the middle?

[vermonster13]

It's the top right of page 3

[onemississipp]

I believe line B to be correct.

I asked measurment questions of Charlie Lamb and here is the post with pics.

 http://www.websitetoolbox.com/tool/post/bowyersjournal/vpost?id=1794034

[vermonster13]

The string length is the length needed to bring the bow to proper brace height +/- 1/2" then three inches is added to that for AMO bow length. AMO length has very little to do with actual bow length. This is if you want to be within AMO/ATA standards.

[O.L. Adcock]

If you are looking for "AMO", neither is correct cause it's based on "string length for proper brace, plus 3".

You can have a bow that measures say, 64 by either method and it might require a 60" string (63" AMO) or a 62" string (65" AMO). It depends on the bows geometry and what string length braces it in the sweet spot. Some bows may be braced correctly at 6.5" and others at 8" even though they are "physically" the same length.

Example "A" is the method used by NAA/FITA as an international standard. My bows measured to 64" using that method will be 65" AMO.

If you are designing your own bow you can't at the get go say you are going to build a 64" AMO bow cause you have no idea what brace height will be the sweet spot. You have to build it, find the sweet spot, then measure string to see what it really is, then make adjustments accordingly. You might have to put the nocks at 63.5 or 64.5 to hit the 64" AMO. AMO standards are a PIA for bowyers and manufactures but it's so it's not a PIA for the end user. "All" 64" bows should use a 61" string, if they don't you'll probably buy at least 2 string and spend 2 weeks getting the right string....O.L.

[Carbon Caster]

AMEN to what O.L. Said!!!!