Main Discussion Area > English Warbow
Hazel longbow, 100# @ 28"
FilipT:
They shouldn't break if I look at the one with the best grain. But as warbow arrows can be torpedo shaped, tapered or barreled, grain always will run off. Will S knows a lot about that. Anyway, I'll try to find the best there is, but first I must see what about feathers and arrow heads.
FilipT:
I read a lot about spining the warbow arrows and it seems to all point that spining them doesn't matter as same as spining the bows with weights such as #50 for example. Does that make any sense?
The thing is I don't see any plans for spine tester for arrows over 28" of length. Arrows of 28" of shaft length are commonly used for 28" draw and a bit lower than that. Plans state that you must suspend weight at the middle and the distance between points on which arrow is suspended is 26".
But for bow that draws up to 30", you will need longer arrows. Does that mean that you need to suspend arrows on points that are 28" apart? Notice that for 28" arrows, suspension is 26", so 2" less. I used same logic for 30" arrows.
I don't know what to do...
P.S.
I see couple of times mentioned on other forums that guys suspended warbow arrows on usual spine testers and spines all come out wrong.
Del the cat:
@ FilipT
For a spine tester the distance between the supports doesn't matter too much because you divide the distance by the deflection.
So if you have the supports at a longer distance you get more deflection so it cancels out.
E.G Say 28" and 0.5" deflection gives 28/0.5 = 56
The same arrow at 26" between supports would give 0.464" deflection and thus gives 26/0.464 = 56
This shows that the further apart the supports the more accurate the reading.... but basically it doesn't matter as long as you remain consistent for any particular set of arrows.
So for warbow arrows you might decide to use supports 30" apart, but for flight arrows maybe 23" apart.
Del
FilipT:
That sounds a bit tricky as I don't know how I would modify support distance when I want. I made today everything except supports. The interesting thing is that I read the following in one of the plans:
--- Quote ---The spine tester assumes your arrow is 28" long. The shorter the arrow is, the higher the effective spine, and the longer, the lower. The thumb rule is 5# for every 1". So, if your dynamic spine is 50#, and your arrow is 29" long, your effective spine (accounting only for arrow length) is 45#. If your arrow is 27" long, your effective spine is 55#.
--- End quote ---
According to this I could make the supports 26" apart and use it for 28,29,30,31, etc. inch arrows except I would add or subtract 5# on measured deflection. Would that make sense instead of making adjustable support spine tester (which I never seen anywhere)?
Also do you use spine testing before putting fletchings and point on or when you have bare shaft of wood?
willie:
Filip
testing is for static spine, or beam deflection. just a reference point to get you started. you can test anywhere along an arrow or an arrow of any length.
--- Quote ---The shorter the arrow is, the higher the effective spine, and the longer, the lower. The thumb rule is 5# for every 1". So, if your dynamic spine is 50#, and your arrow is 29" long, your effective spine (accounting only for arrow length) is 45#. If your arrow is 27" long, your effective spine is 55#.
--- End quote ---
the info in quotes is about dynamic spine, or how the arrow is supposed to act when you start shooting it.
google "stu's dynamic spine calculator" for an excel application.
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