Simple test to determine which way your arrows spin
Which way do my arrows naturally spin when they come off my compound bow?
That’s a common question archers ask before sitting down to fletch a fresh batch of arrows. If you plan to incorporate a right or left offset and/or helical into your fletchings to promote arrow spin, you might want the arrow to keep spinning in the direction it naturally spins anyway.
This is called indexing your arrows. And there’s a super simple test you can do to figure out which way your arrows want to spin as they leave your bow.
The reason an arrow spins one way or the other has nothing to do with whether you shoot right or left handed. It is commonly considered to be related to the direction the bowstring is twisted, although there have been discrepancies observed with that theory.
But don’t worry about string twist. Here’s the simplest way to determine which way your arrows naturally spin when shot from your bow without any influence from fletchings.
Take an unfletched arrow and nock it on the bowstring. Draw a short line down the center of the top of the shaft, just behind the nock.
Stand about 10 feet from a target and shoot the arrow. When you inspect the arrow, you will see the line is now to the left or right of its centered position when it was on the bow. If it’s to the left, then your arrows spin counterclockwise. If it’s to the right, then your arrows spin clockwise.
Archers often ask at this point, “How do I know the arrow didn’t spin all the way in the other direction and stop there?” The simple answer is that it doesn’t have enough time to spin that far in such a short distance. But you can check to verify this further.
Take two more unfletched arrows and mark them just as you did the first. Now take three steps back from where you shot the first arrow and shoot a second. Take three more steps back from that spot and shoot your third arrow.
When you walk up to inspect all three arrows, you will see the graduated rotation. As you increased the shooting distance, you gave the arrows more room to spin.
So let’s say your first arrow spun a bit to the left. Your second should be a little more to the left and the third arrow even more to the left. If the arrows truly were spinning clockwise, then the graduated rotations would be the opposite.
Once you determine your arrows want to spin counterclockwise, then you know to fletch using a left offset and/or helical configuration, which will enhance that counterclockwise spin. If they spin clockwise, use right offset/helical.
An exception would be if these are hunting arrows, and you are shooting fixed-blade broadheads which have the blades set at an offset - which is almost always a right offset. Fletch to match the blade offset regardless of the results of your bareshaft test so your broadhead and your fletchings can work together to promote arrow spin.