Arrow FOC - How to measure, what Extreme FOC is, and it's benefits in archery.
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- เผยแพร่เมื่อ 6 ก.พ. 2018
- Knowing your arrow's FOC (front of center) is a great starting point for building accurate, effective, and deadly arrows for both target shooting and bow hunting. FOC is a percentage front of center for your arrow's balance point.
It's helpful to think of an arrow as two levers and a fulcrum. anything in front of the balance point of the arrow works against us to guide the arrow to the target. Anything behind the fulcrum/balance point works for us. High FOC and extreme FOC (EFOC) arrows seek to minimize the effects of the front lever arm while maximizing the steering ability of the rear.
By shooting EFOC arrows we can shoot smaller arrow fletching, arrows recover from archers paradox more quickly, and penetration is more complete. Additionally, EFOC arrows tend to fly better from a wider range of bows. You will probably need to move to a higher spine range to increase your arrow's dynamic spine in order to shoot higher FOC arrows.
In this video I show a few examples, carbon arrows, and wood shafts to demonstrate the difference. I began playing with high and extreme FOC arrows with my longbows and recurves about 8 years ago, after reading Dr. Ed Ashby's work on the subject, and have found them much more efficient than the standard arrow of 20 years ago.
In future videos we will be building and tuning EFOC arrows.
Website: www.twistedstave.com/
Facebook: / twistedstave
Instagram: / clayhayeshunter
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Better explanation than all of the long-winded bow hunters on TH-cam. Thank you, Clay.
One of the best discussion on the many aspects of arrow design I've seen in a while. Thank you.
Glad it was helpful!
As a new archer I’m bowled over at how much information you provide. Thank you so much for your clear and skillful explanations; your dedication to teaching shines through. And, your model is way more effective at showing geometry of form than drawings I’ve seen elsewhere. Thank you for all you’re doing!
Glad it was helpful!
I'm new to archery, so most of this was new to me, but you presented it very well. To the point. Informative, with no wasted time.
Talk about a total winner video Clay! I know my arrow tuning... I thought... but this was just so smooth! Loving it man! Thank you!
Thanks, I'm excited to start the new building vids. they should be fun.
I've heard a lot of explanations of what FOC is, and i now finally get it. thanks Clay!
You’re welcome Helen.
Great video Clay! I got my first whitetail with a cedar arrow last week. 3 rivers hunter arrow 50-55 spine full length with 190 grain meathead weighing 620 grains total shot from 48# bear grizzly. Quartered hard away I took 3 ribs going in and exited in front of the opposite shoulder. My accuracy/consistency improved when I started testing foc and heavy broadheads. And that penetration my setup achieved really impressed me.
As always Clay, very informative and helpful. Thanks
I went EFOC last year and couldn't be happier with it.
Awesome explanation of FOC. Thanks Clay.
more to come!
This is a great video Clay! You broke down the math just right. I was giving some cedar arrows to practice with. Recently purchased carbons. I really enjoyed the flight of the cedars better. Between your videos and books I hope to be building some arrows this winter. Thanks for all you do.
Looking forward to more knowledge on that for sure. Thanks
But putting the FOC math formula in the description would of being helpful ((BP/TL)-0.5 x 100+%FOC
Clay .... with all the TH-cam videos I have watched I have never written a comment... until now. This video was terrific. Very informative, easy presentation style and concise without a whole lot of "fluff". Unlike so much on line these days you have made a valuable contribution to people's knowledge. Thank you and keep going... (ps Hi from Australia)
Thanks Neil! There a bunch more bow building focused videos at www.patreon.com/clayhayes if you’re interested in that aspect of archery. Ch
Excellent. Thanks Clay.
Cant wait for new video. Thanks
Tail-taperig shafts really is pretty easy, and you can do up to about 1/3 of the shafts length without changing the measured spine.
A couple years ago I bought a bunch of bamboo shafts from China off Ebay. The quality was great. I drilled out the pith on the front 7-9" with a long 1/4" drill, and inserted homemade hardwood dowels. Then I drilled out the tails and added only a short plug to allow a nock taper.
Those things weighted about 725 gr, and they FLEW!
Lots of good old-timer tricks like that, if you take the time to learn how and fiddle around.
I'm also a fan of the guy who invented the "Rep-arrow" system. Adding ash foreshafts does multiple good things for a cedar arrow.
Some native tribes still bowhunting today, use a very long arrow. It moves the center of gravity further forward and makes them more stable. It may seem silly to have 6 inches of arrow, or more, hanging out in front of your bow when drawing, but do the math, it does make a difference to the FOC when you have to use natural materials.
Very succinct Clay. This is a lesson for every archer whether they shoot trad or even crossbows. The science you so masterfully explained remains the same and I would go so far to argue that if you understand this principle, the whole industry of mechanicals probably wouldn’t have ever came about. I’ll duck behind some cover now, lol!
Thanks Wayne!
Thanks clay, your information helps a lot. It's been a journey for me. I started archery hunting wild boar in Hawaii about 10 years ago and the archery shop set me up with 8 gpi carbons and a 100 grain 3 blade , I didn't know any better because I had always hunted deer with a rifle in South Dakota. Back then there wasn't a lot of talk on the internet about foc and weight of arrows . The Ashby studies were pretty much buried by the archery industry because they wouldn't have the market they have today if every body who picked up a bow read them. I have not shot a traditional bow but you are inspiring me to do so. Keep the videos going. Thanks!
Yep, it was all about speed. But even the compound shooters are starting to take notice of higher foc and arrow weight.
Stuff like this is why I watch your videos.
Thanks Larry.
Great information on foc, very well explained. The arrow flight is what I was interested in. I finally settled on a 500 grain 340 spine gold tip pro. Foc is just under 15. At 67lbs, 31 inch draw, I've found its the most accurate for me. I really loved the 511 grain 400 spine with the 20 foc, but the flight at times were erratic. Your a true expert, someone we all need to listen to.
Not sure your arrow length but a red flag here was you chose a weaker spine for your higher FOC arrow. If you ever want to revisit higher FOC you should shoot a stiffer spine than what you normally do.
Good stuff. Thanks for the info!
you're most welcome
Apreciate the video clay. I've hunted my whole life and this is my first year bowhunting and I got everything about arrow spine down but I had gotten a heavier arrow head and put it on the same spine shaft and couldn't get the thing to fly straight. Now I've heard of foc but never knew it was that important. Now I know why my arrows keep hitting to the left with the larger arrow head
Excellent video. Lots of good useful information. Nice to see that you also like a heavier arrow so that you get full or pass thru penetration. I too would rather have two holes than a super fast arrow that leaves less penetration.
Ok professor you have my attention, great informative video
Great pro tip thanks.
thanks
Just learning archery. Good to what the FOC is up with arrows. :)
Man Where was this video 25 ago. subscribed
Good video Clay. Wish the compound community would learn a bit about arrow lethality.
I’ve noticed the compound community talking more about this stuff lately!
Cool stuff 👊
Very interesting! Thanks!
Glad you liked it!
One thing worth considering is that the more you increase the distance between your arrow's center of mass and center of pressure by distributing more mass at the tip, the more readily your arrow will yaw into any crosswind it encounters on its way to its target. For shooting in windy or gusty conditions, an arrow with proportionally less mass at the tip and more mass in the shaft may perform better.
This is great I love the ed Ashby lethality studies quite interesting.
Yes they are. So much to learn there!
Excellent...
Very good! I never knew this! Thank you.
Thanks man
I have some GT 3555s that I used with my 48# longbow, but I got new arrows for it and wanted to use the 3555s with my 25# Sage, so I put 100 grain brass inserts and 250 grain field points on them to drop the dynamic spine. The FOC on them is now 28.6%. 😲😂 They don't shoot half bad out of the Sage either. 👍
thanks always wondered. what you make from the flooring wood?
Useful
Clay, I have a question. I wanted to move to Doug Fir arrows due to how durable they are, but I’m worried about penetration when hunting with such a heavy arrow and low FOC. I’ve seen arrows splinter/shatter upon shooting after they are lightly damaged and they can do some real damage to someone’s hand. That’s why I wanted to go with Doug Fir over some of the other lighter woods suggested for higher FOC. How easy do those lighter woods shatter when shooting? Especially with a heavy point or broad head to push up the FOC?
Great advantage to have same arrows shoot well in different bows.
Clay have you played with the a&a fetching with the turbulator? Just curious if it has worked for you or not.
Thankyou
What are some arrow brands you would recommend?
A full taper on the shaft can help with the shaft weight overall and automatically pushes the FOC forward.
Like medieval arrows!
thanks for the video ...Im always experimenting with different weights on my field tips . carbon arrows usually .....now I just bought some Easton aluminum 2117s arrows , took off the vanes adding fletchs to them now ....alot heavier shaftsto start with , so will be trying out different weights on my tips to see what happens ...they hit my targets with authority with the extra weight I have noticed ....but have to figure them out ( tuning) and see how good I can get them to fly .....
Any idea where to start with spine on a 45 lb bow at 28" pulling 28" if you are trying to accomplish EFOC?
Same question with 55lb limbs at 28".
I have 450 Spine arrows that I am thinking are too weak for EFOC arrows at 45lbs.
Bow is cut very very close to center shot.
Clay how do you get a high FOC with cedar arrows? Is there inserts? Or is it just a heavy tip on the front. I’ve got a long bow coming and have an wood arrow test kit from and glue on tips from 3 rivers coming. Just want to do it right.
I have 2 questions one is field tips avalible on DVD? And 2 do know anything about restoring vintage bows
I had a hard time getting hfoc on my woods. Until recently I’ve got tapered mahogany with 145gr tips and achieved close to 20% foc. Arrow length 27.25” bop. 3x3” feathers.
That’s great for wood!
That’s great. I never knew how to calculate my FOC before. (In the ballpark of 20.5%). Good information here.
Hey do you make it out to ETAR?
I haven’t yet but will at some point
Clay... great vid. You're making this old bow hunter feel good about the younger generation ...YOU !
Also, try 2 fletches. Better penetration, less drift in wind and even lighter back-end weight. Thanks.
Good tips!
Thanks for accepting my little bit of input graciously. Just passing on what little I've learned to someone who cares and is on the same page.
Remind me to tell you about my ex wife bringing home the bacon from Africa with a recurve, barreled maple shafts, Bear Razor Heads and NO fletching !
I shoot a long bow and have a 27 inch draw I have 100 grain outsert sand 150 grain head what spine do you suggest I use I’m gonna be shooting the black eagle instincts. Thanks
Also, does f.o.c. directly affect the arrow nodes or is it just the spine/arrow length? I'm wondering because I've noticed that if I draw to where the front node area is contacting the shelf/riser/rest it makes for a good flight. But then again, I tested this at only a few yards.
if you're shooting a cane or bamboo arrow with raised nodes and settle on a node when you reach full draw, then theoretically this would affect your dynamic spine. This would be due to a wider spot on the arrow being in contact with the strike plate just at release. I think it would have the same effect as shooting a larger diameter shaft or, perhaps, shooting with a thicker strike plate.
Same can be said of Aluminum looking for a 2016--2018 or higher for most hunting weight bows something that has the 17 or lower on the outer scale as a wider arrow to increase the poundage of the bow. The problem is you don't want 20 or higher on the last number or then it gets hard to fix the tip with FOC since glue on broadheads for target arrows are made for wood shaft or bamboo so they will be wider. I however like a less like 10% forward weight and use an arrow that is minimum strength for the poundage of bow like right now I have a 45 pound RECURVE with a Fast Flight string that I pull 35 pounds with at the draw spot for said bow, to front part of ear and I use 500 or 1916 Aluminum arrow a tick as it says on the arrow for the bow with being 30 inch arrow. What I do is make the arrow so the balance is more neutral but works due to being a tick lighter in spine with aluminum then what I need just a hair less where I could use a 450 19.5 16 or 400 2016 for the spine on my bow for the poundage and FPS my bow is getting with the Fast Flight. I find the fastest an arrow can go off the shelf to the poundage and string type to its max point by getting the minimum spine of arrow you can use with a wider diameter for hunting/outdoor use is what I am going for since I find faster one can get an arrow off the shelf the less time there is to mess up with the bow by using the lightest arrow one can and have it just heavier then balanced.
How about arrow length? Does it have to match with draw length to have good arrow flight?
Hex camouflage suit good for getting up close for elk and deer
Did you explain why to subtract 0.5 in the equation (and I missed it)? Is it multiply by 0.5 to divide the total arrow length in 2, as in the "Center" point in FOC?...then you are calculating the percentage deviation from the center?
Yep, you’re looking for the percentage front of the half way mark.
How to add wt for FOC to reed/cain arrows
What is your opinion on 2 blade vs 3 blade broad heads and would you shoot a two blade with a compound? I know you shoot traditional self made bows, just wondering what you thought. Thanks, Danny
The type of bow doesn't matter. I prefer a heavy, two blade, single bevel with a high mechanical advantage. There is a ton of research via the Ashby studies that proves better penetration on marginal hits where heavy bone is encountered. With an EFOC arrow with the above mentioned broadheads, a compound could shoot through a brick wall!
Could I theoretically make a bow with a hole in the dead center of the riser, to launch the arrow through? Just curious what would happen.
Yes you could. But it would be difficult to tune I think.
What is the arrow set up you like to hunt whitetail with? FOC, arrow weight, tip weight?
I shoot for 20+% FOC and a total arrow weight of 550-650 grains depending on the bow.
How do you got it with wood shaft ? Thanks for all your videos !
So if you're severely under-spined is there a risk of or is it possible for your arrow to break?
yes there is. but you'd have to be way underspined.
Thanks. I was wondering because I was shooting 31”/500 spine carbon arrows from a 55# recurve (a little less at my draw length). According to the charts I'm supposed to be at 340 spine. They shot straight and accurately, though I was only at 15 yds. But I was afraid I was pushing it on flexibility and that they might eventually snap under the weight of the release.
My Pro Shop never mentions these details. I purchased a set of custom cut arrows and was handed them without explanation. No mention of arrow or tip weights or FOC. I am a bit lost about what the FOC should be. Doing the math, one set of arrows has a FOC of ~13.65%. Is the point of FOC to improve accuracy or penetration? What is "desirable" or prefered FOC?
I'm guessing your pro shop mainly focused on compounds. 13% is fine so long as you're getting good arrow flight. But, it has been proven that FOC above 18% aids in penetration. Higher FOC also allows you to use smaller fletchings which helps the arrow maintain more speed and momentum down range.
Hay I'm little confused. Once your dun with the equation and get -49.2869565217 do you just look at the last 3 numbers 217. Is that wear you get the 22%? Thanks
You must have done something wrong.
@@clayhayeshunter I did 20.5 ÷28.75-0.5×100 and got that
@@lukebonagurio4503 you need to include the brackets! ((20,5/28,75)-0,5)x100 = 21,3 you calculated (20,5728,75)-50
You refer to "bumping up" the spine to accomodate a heavier head. Do you mean using a stiffer spine? (500 to 400 spine) Or bump up the number (i.e. 500 to 600 spine)?
Stiffer spine
I hope this isn't a silly question, but why not completely remove the fletchings?
If a bow is perfectly tuned and with 20%+ FOC arrows, what are fletchings actually there for?
They’re there because in the woods we can rarely achieve perfection in our shooting. Wind, uneven ground, etc can cause little variations. Fletchings are insurance against all that.
@@clayhayeshunter That makes a lot of sense. I went stump shooting with bareshafts yesterday, and while I could usually hit at least close to where I was aiming, I did see a lot of variance in impact angles and even grouping that I don't think I normally see with fletchings.
Anyway thanks for the reply, it's helped clear that up for me and my Dad.
When shooting just field points you probably can lose the fletch. I do it all the time while playing. With broadheads they will steer the arrows if there is no overiding guidance from the rear.
Wow! Who knew?
I’ve got a Damon Howatt hunter by Martin archery 65 pound at 28 I draw 30 so probly 70 pounds, iv just got x12 fmjs dangerous game in 300 spine, 15.5 gpi so with fletch and insert I’m 555 grain without a head, with a 175 grain head I’m 740 grain arrows which basically 10 gpp with a 16% foc.. have 5 inch fletching though but shot all 12 through a Chrono and got 190 feet per second. Does this setup sound ok? Please reply I’m new to this.. still can’t hit bugger all yet lol
I’m hopeing this will kill wapati and large red stags easily, might be hard to find broad heads at 175 grain in New Zealand though
Sounds plenty good to me so long as the arrows are tuned and flying well. And you hit them in the right spot😉
I like 11%
What’s your point weight on the cane?
200 grain
Hi Clay!
Shooting a Longbow with 55-60 in Spine(Wooden arrows), My FOC is measured to 13%, if I increased it to to 22%, I need to change my 125gr tip to a 277gr tip, and thats far to much when shooting 3D on distances up to 45 yards. I could tapered that aft part of the arrow from 11/32 to 5/16, I think, and increase the tip weight to lets say 150gr or maximum 200gr, I guess that would help some to move the FOC forward, and on top I guess I have to increase the spine on my ceder shaft to spine from 55-60 to at least 60-65.
My bow is a Grandplains 38lbs with 28" in draw lenght( not for real hunting) but excellent good shooting bow for 3D contests, I love it, this is my 5th hand made bought bow, and for sure the best so far.
What is your advice on this Clay?
The light wood Spruce, I understand, but Can? did not get that?
I only been shooting for 5 years, but done a lot of tests with spines, arrow lenghts, a lot of bare shaft shootings with different spined shafts, feather sizes, cutting feathers, 4 feathers straight etc etc, using a fast flight string works excellent.( My wife thinks Im totally crazy)
So this is my firts time to get into the FOC, and I always try to get to the bottom of things, due to Im really curious on Longbow shooting.
Maybe there is somebody more than me who are curious about the FOC? Im open for all kinds of advices.
Thanks also Clay for many really interesting Videos on Utube, you are really excellent to explain things very good!
Anyway Clay, and all nice Bow Shooters on this side!!!
Wish you all a Happy New Year!!!
Swedish guy, living in Spain!
Hello Lars, perfect arrow flight is more important than high FOC. So don’t sacrifice good tuning just to get FOC up. But if you can get both while staying within reasonable total arrow weight then go for it. Tail tapered shafts will help.
@@clayhayeshunter Thanks a lot for answers, I see what you mean, I will give it a try to taper the aft part a bit and test with a slighly increased tip weight, if it doesnt work better, I stick to the original made arrows. The fun part is ofcourse to give it a try.
Good luck and have fun!
FOC 17.24 carbon arrow 5" low cut feather. 145g tip total wt 425g. how that sound?
A little light for elk in my opinion but find for deer. I'd bump up total arrow weight to 500 minimum. if you push foc up you can reduce fletching and have less drag which will retain more energy down range.
You should always have the heaviest arrow and FOC that will allow you to maintain your accuracy for maximum arrow lethality.
full length taper your woodies to help with FOC
I'm learning archery for survival reasons so I gotta know this stuff. For some reason, most of my fibreglass target practice arrows keep nocking left. I gotta fix it.
Could be a form issue (not getting proper back tension on your drawing arm side) or the spine of the arrow could be too weak. You can either shorten the arrow to make the arrow stiffer, work on your form, or use a lighter tip on your arrow (which is similar to stiffening the spine).
What do you stain your cedar arrow with
I don’t stain them. There’s a chapter on arrow making in my book.
Clay Hayes cool thanks I will check out your book
Link to Dr. Ashby bow hunting foundation website: www.ashbybowhunting.org/ashby-reports
Can you fire a carbon arrow through a board bow?
Sure.
Will the rubber fletching effect the shot or do I put feather ones on there ?
If you want to shoot carbon, feathers are preferable.
The arrow flexing as it leaves the bow is not the archers paradox.
Accordingly, this arrow showed here would have a FOC of 21,3%! General recommendations is 11-15%. What has the author of this video to say about that? More is better?
Look up the research done by Dr. Ed Ashby. But in short, yes... for hunting. More is better so long as you're still getting good arrow flight.
I figured it out the calculator was messing me up
Perfect!
The FOC formula at 3:19 is wrong!
AMO standard formula for FOC is "100 x (A-L/2) /L", where A is the balance point measured from nockthroat and L is the total length of the arrow.
different ways to get to the same answer.
So your measuring the arrows length only to knock throat, that's draw length. The Arrows fall length is full mass complete knock . The bow pushes an arrows mass not it's length .
I don’t think the Native American were out here doing foc math like this ? Any other way to get the desired out come with out the math?
brother ,lets say you got wooden arrows,couldn't you just take weight off the back ,carefully remove some material ,TAPER IT IF YOU WILL ALL THE WAY TO KNOCK OR FLETCHING ?
Yes, that will help. I shoot tapered shafts when shooting wood.
@@clayhayeshunter Yes indeed ,thanks man !
Recover from acceleration flex not paradox, wish people would get paradox correct.
BLAH, BLAH >>this is like separating pepper and fly shit...