Archery Arrow Level for Determining FOC

If you are an archer like I am, and you work on your own equipment rather than dump $$ at the archery pro shop, you probably build your own arrows.  It is a well known fact that in any launched projectile the Center of Pressure (exerted by the vanes), must be aft of the Center of Gravity for stable flight.  This will work for wooden arrows, aluminum arrows and carbon arrows although there are many more options for balancing aluminum and carbon arrows than those made of wood.

There are a wide variety of materials today that once assembled result in something that looks like an arrow.  Will it fly, straight and true?  This level will help you find out.

It includes 2 pieces, a base plate and a self-centering arrow level.  It requires 2 M10xM3 bearings, 2 M3x14 socket head cap screws and a square bubble level “Mini Bubble Spirit Level 10x10x29mm Square Levels” from Amazon at https://www.amazon.com/dp/B09BPYB7T6?psc=1&ref=ppx_yo2ov_dt_b_product_details

The bearings are pressed (carefully!) into the uprights on the base, and the square level is pressed into a slotted channel in the top.  Don't tighten the screws too tight as you want the self-centering level block to pivot freely in the bearings.  Accommodates arrows up to almost 10mm in outside diameter.

To use, slide the arrow into the leveling block until it self-centers in the V of that block.  Slide the arrow back and forth until the bubble level reads center.  Gently capture and hold down the arrow with your fingers in its balanced position and mark the arrow at the outsides of the V-block with a pencil.  The center of those two marks is the Center of Gravity of the AS-BUILT arrow.  Measure the arrow with a tape measure to find its geometric center (from the nock throat to the point end of the ARROW SHAFT).  Now take the CoG distance in front of that and divide by the length of the arrow shaft just measured and multiply the result by 100.  The FOC or Front-of-Center measurement (somewhere around 6-10% for good flight stability), is the resulting value.  Mine come in somewhere between 7 and 8%.