Extreme front of center (EFOC) arrows aren’t a new concept. They’ve been talked about in traditional archery forums extensively for the past 10 years or so. But understanding what’s happening and why higher FOC influences and arrows flight and penetrating ability can be a little confusing to folks, especially those new to archery.
In this video I explain what FOC is, why it’s important, and how to measure it. Once you have two measurements, the formula to determine FOC is simple. You’ll need a total arrow length, from the throat of the nock to the base of the tip, as well as a measurement from the nock throat to the balance point. Plug that into the following equation and voila – %FOC!
((Balance Point/Arrow Length)- 0.5)x100=%FOC
All of this comes directly from Dr. Ed Ashby’s research into arrow lethality and penetration. There is a great discussion board dedicated to the topic at www.tradbow.com so be sure to check that out. You’ll find tons of great info on EFOC arrows there.
In future videos we’ll be building EFOC arrows in both carbon and natural material shafts so make sure you’re subscribed to the YouTube channel and signed up for the mailing list to get notified.
Great video; I am aware of FOC, but you really explained it well. Once again, great info.
Clay,
Your comments on high and ultra high FOC are right on. I recently went to Africa for Cape Buffalo and for that trip I wanted all the penetration and accuracy I could get. The arrows I shot had a 22% FOC. I have a 32″ draw with my compound which works against high FOC. With shorter draw lengths higher FOC is easier to obtain. I found this set up to be more accurate than my previous hunting arrows, they were around 8%. I have yet to change to a higher FOC arrow for my recurve and long bow because of the lack of availability of heaver points for wooden shafts. If you know where I can get heaver tips please let me know.
Jeff
Great vid clay!
Hi Jeff, there are lots of options for heavy glue on heads. Tuffhead and Abowyer are both making 300gr heads. I think Grizzly also makes a heavy head. I’ve used both the tuffheads and grizzlies and both are good options.
Clay
I recently listened to Dr, Ashby videos and have read all of his papers. I am now, since Dr. Ashby’s studies are based on his results of shooting into animals, a believer in high FOC. According to Dr. Ashby numbers, a 650 grain carbon arrow for my 49# hybrid longbow should be a reasonable combination. I am looking forward to your upcoming video on building high FOC arrows.
Good Hunting,
Ross
Hello Clay!
You’re videos have been a huge help to building my own arrows and soon building my own bow. Thanks for sharing!
A few months ago you shared a video where you made some Tonkin cane arrows. I’ve been using 3/8 oak dowels from the store as shipping shafts to Fairbanks Alaska is cost prohibitive. But in the interested of trying to up my FOC and interested in trying Tonkin cane. I draw my 60 pound at 28 inch Samik Sage to 31 inches, and I’ve got some 230 grain Grizzly broadheads I want to use. What spine to you recommend I use? I’m going to be hunting moose, caribou, and bear with this set up. Given my draw length and point weight it seems like I ought to use heavier than 70 pound spine.
I always look forward to your videos, hope you have a good season!
There are a few spine calculators online that might help you decide what spine to start with. But they’re not the most accurate things. Before buying a bunch of shafts, it might be worth grabbing a few larger diameter carbon shafts just to test what length, spine, point weight combos work well. then you can use that to help choose an appropriate wood or cane shaft.
Very interesting. I have been toying with trying this myself for sometime now. I am glad you demonstrated this jig and explained the quirks with it.Thanks loads.