I used to make and sell wood shafts, mostly Poplar and Hickory.  I have three different spine testers and all at 2# weights and all are 26″.  One of them I made out of 1/4″ aluminum angle and has a dial caliper and I use a deflection chart to measure the shafts.  It is not going to shift any to alter the readings.

All the orders I got were wanting the physical weight of the dozen arrows to be within 5 grains of each other and I would tell them all that the shaft weight would change during the seasons and I always got a puzzled look.  Humidity changes during the seasons and wood absorbs and releases moisture.

Then I would ask if they were going to seal and crest them.  “Sure” was the answer and I asked do you measure the same amount of sealant and paint used for each shaft.  Do you measure out the same amount of glue for each point and nock?  That got a lot of people scratching their heads.  No two wood shafts are going to have exactly the same physical properties as to density even cut from the same tree.  One will always soak up more sealant or paint than the one next to it and when you are measuring weight in grains it can be a wide spread at times.  I have weighed my finished shafts at different times during the year and it is surprising how much moisture they can absorb or release even after they are sealed and painted.

It was amazing to me that a lot of the customers had no idea about the properties of wood.

I have looked at lots of spine charts and they are puzzling things to try and sort through.  I’ll stick with the traditional wood shafts.

Now, you want to try bamboo or rivercane shafts?  That’s another subject.