QUESTION: Exactly what is front of center (FOC) and how do you measure it?
BY FREDDIE TRONCOSO
Forward of center merely refers to the actual location and balance area on any given arrow shaft. This phenomenon occurs when we add a weighted point in the form of a target/field or hunting broadhead on the forward end of the arrow.
As we realize and have known since the dawn of early man, adding weight to the forward end of a spear or arrow shaft will allow the projectile to track better and to stay on the course. If we did not add weight to the forward end of the above mentioned projectiles, they would flip end over end (without fletching) and would not carry very far at the great distances.
Continuing with this explanation, the distance from the fletching end to the forward end of an arrow is important in determining the F.O.C. or forward of center balance location on the shaft. The forward of center point or nose heavy attitude of the arrow must be at least 7 – 9% for target arrows, 9-16% for carbon arrows and a minimum of 10-15% for most hunting arrows with broadheads.
Here is a diagram that should help you to use and understand the proper approach to determining your own particular F.O.C.
TO DETERMINE SHAFT F.O.C. (Forward of Center) BALANCE
Measure the shaft length from bottom of the nock groove to the end of the shaft cutoff.
- Measure and mark the absolute center of the shaft.
- Find the exact location where the arrow balances and makes a reference mark on the shaft.
- Measure the distance between the exact center and balance marks of the shaft.
- Divide this measurement by the total length of the arrow and multiply by 100. This gives you the percentage of forward to center balance of the shaft.
The percentage of FOC must be at least 10% of more when using broadheads and from 7% to 9% as applied to target arrows.