Building the wood arrow Part 4...Understanding Spine groups

      When we discuss arrows, and arrow spine, we must necessarily discuss static and dynamic spines.  Static spine is the spine that is found when flexing the arrow between two points and determining the rate of deflection from straight.  This is usually accomplished by using a spine tester which can be either store bought or home made.  There are examples of spine testers and how they test arrow spine, available by a casual search on the internet so I won't go into great detail here. Dynamic spine is the flexing of the arrow as is reacts to being pushed by the string upon release and is affected by other factors such as feather weight, point weight, arrow finish, as well as shooting form i.e. string release, steady bow arm, etc.  Here's where the fun really starts when making a good wood arrow.

      First, we need to understand that wood arrows are spined and sold in batches, called groups, of supposedly 5# spine ranges.  In the old days this was true.  There are still some arrowsmiths that group arrows in 5# groups but it's becoming more and more rare.  The grouping of arrows in these 5# ranges is acceptible because humans cannot shoot the variable differences in the group.  A shooting machine can, but we cannot.  So 5# is a very good way to sort and group arrows.  If only...

      Arrows purchased commercially are commonly grouped for example 40-45, 45-50, 50-55, 55-60, etc. Anyone notice the problem?  Those are actually 6# of spine range per group, not 5#.  What do we do with the poundage that is shared by both groups?  A true 5# spine range is 40-44, 45-49, 50-54, 55-59, etc.  Understanding why this makes a difference helps us to fine tune our arrow selections.  If your bow is 40# at your draw and you are making up good arrows, do you choose 35-40 or 40-45 spine range?  Say you are new to the wood arrow making venture.  You order one dozen arrows of both groups to cover your bases for your testing.   Due to the nature of wood arrows and the spining and sorting process, you get mostly 35-36# and 44-45# in your two dozen arrows.  You try to shoot them after building and the arrows shoot all over the target face.  Right there you give up on wood and go back to your aluminum or carbon arrows and say wood is no good.  This isn't a fault of your shooting necessarily or of you arrow building capabilities per se'.  It's a fault of the arrow business.  So how do we go about getting around this issue?

     I recommend to any serious archer wanting to make and shoot good wood arrows, to buy a grain scale, and a spine tester....and buy arrow shafts in some kind of bulk quantities.  I know this sound expensive, and yes, there is an increased upfront cost.  However, if you've seen the prices that are charged for a dozen carbon arrows these days...wood arrows and their necessary tools for production are relatively inexpensive when the years of enjoyment of building archery equipment using your own tools is factored in.

    I like to buy arrows in a minimum of two to three dozen lots.  More if the budget allows me to.  This allows me to spine all my arrows and group them myself, in tighter spine tolerances.  I find, even from good wood arrow shaft suppliers, that in 24 shafts from say, 65-70#, there may be half in the upper end and half in the lower end of the spine group.  Using my own tester I can sort these into two sub-groups of say, 65-67# (which is a 3# range)  and 68-70# (another 3# range) and from there will tweak the dynamic spine as I build the arrows and add the point weight.

    Finally...after all the blogs of getting shooters to work on their form, start shooting their Hill style longbow in a fluid motion, allowing the mind and hand and eye coordination to work together to get a consistent fluid draw length that remains the same for each shot, whilst still remaining casual and relaxed...finally we're starting to build a good wood arrow that will...

     Shoot Straight.