Clay HayesMemberJuly 3, 2009 at 11:25 pmPost count: 418
I’ve done some research and have some good ideas on how to get 20% FoC on my woodies. My question is, what should I be looking for in static spine for that much weight up front? It would seem that I would need something like an 80# spine to handle a 250 gr. broadhead.
Steve Sr.July 4, 2009 at 1:04 amPost count: 344
Your draw length, bow weight and if your bow is center cut will all be factors determining what will be required as well as your release, to a point.
In about 10 days or so, Ill be more informative here on that. Ive 12 dozen arrows coming in several spine ranges out of my 50-55lb bows.
When I find a functioning arrangement for myself I will contact you here but your own statistics on the above information will largely play a part in that choice. Your and my working combinations could easily differ.
Some here may tell you the EFOC is very difficult to reach but Ive some very very close now with just what arrows I had that shoot very well.
Ill also be comparing Woodyweights to the “interior” footing method on various wood and also some Tonkin shafts to reach EFOC.
I too am interested in seeing what combo is giving other woodie shooters something in that range.
David PetersenMemberJuly 4, 2009 at 3:22 pmPost count: 2749
Clay — if you don’t mind sharing, how are going getting 20% FoC on woodies?
Steve — I’ve gone the WoodyWeight route and really like they way they make my arrows fly. But my test shooting at angles into hard backgrounds (pine tree) has them breaking apart far more often than the usual problem of cedar shafts breaking behind the head. As much as I wish this easy fix could be an answer, I just don’t trust them behind broadheads for big game. The only setup I’ve yet tried that provides EFoC and actually strengthens rather than weakens wood shafts is using an external footing via aluminum shaft tip. This has the advantage of allow you to use screw-in heads and weights, but the disadvantage of looking clunky and compromise the all-woody goal if that’s what you’re after. I also tried internal footing via drilling and inserting nails, but the added weight was nowhere near enough. I know that O.L. Adcock was experimenting with a really heavy stiff wire insert, but I can’t recall what it was. This is a huge challenge for those of us who have seen the remarkable gains in accuracy and penetration EFoC offers, yet prefer to shoot woodies. Even purpleheart footed shafts don’t come close. dave
Clay HayesMemberMemberJuly 4, 2009 at 8:19 pmPost count: 418
I’m at about 17% just by tapering a 29in fir shaft from 23/64 to 5/16 then putting a 160 gr. head on the end. If I can add another 100gr (internal footing?), or use a 260 gr. broadhead, I’ll be a smidge over 20%. The problem I’m running into is that my arrows are way underspined with that much weight up front.
Is there any way to get a good idea of what spine I need to handle that kind of setup? The shafts I’m shooting now are around 50#s and they are a little weak with 160 up front.
all that is assuming I’m calculating FOC correctly!
Steve Sr.July 4, 2009 at 10:29 pmPost count: 344
Here is a link to Rose City Archery and in the FAQ there they give you a “rule of thumb” they use for heavy heads.
I want to use 145 grain and 160 grain heads on my arrows, do I need to change the spine weight, from what I normally shoot with a 125 grain head, to use these heavier heads?
You will need to add 5 lbs to your spine weight for the heavier heads or increase 1 spine weight range. For 190 grain broadheads you will want to add 10 lbs or 2 spine weight ranges.”
I think I can hit 20 percent fairly readily with a couple choices of tapered shafts.
Ive some 70lb spine hickory that are 14% with a 160 grain head but WAY over spined yet but with the same head, Ive got other shafts that show 16-17%.
Depending upon what grain weight of arrow you wish to end up with, of course, the lighter the physical weight of the shaft is, the easier a EFOC is reached.
The “trick” for me is hitting BOTH the EFOC and keeping the desired total grains in arrow weight that I want to try.
Dr. Ashby’s results are not being questioned but, I know me, Ill have to try that heavy hickory and match the weight if I can with a lighter shaft but more FOC.
The switch to carbons is the “logical” choice but just not within acceptable parameters for my own use. No offense intended at all, please.
I ALSO have some heavy FIBERGLASS that do indeed, have hollow shafts. I expect to hit about any FOC I want with them AND keep a hefty total arrow weight.
The previously mentioned Tonkin shafts also show promise, IMHO, with the natural taper of the shaft and the natural small hole within them.
I tend to “over do” things or attack them with too much enthusiasm, and am cursed with an excellent imagination so…beware! LOL
Ive high hopes for the fiberglass arrows but will give ‘er a go on the woodies within the selection I purchased.
Thank you for that input! I had wondered about the breakage behind a head with a really high mass up front. I’ve something I want to try on the woodies and appreciate the “outsert” info. If all else fails, that is an option.
I believe I can add 100 grains to a woodie shaft tip and maintain the strength, if not make it stronger, then put 200 grain head or close on that.
Whatever FOC it ends up with and still shoots well will be the one I try. Ive no “magic number” that I need to hit since using them on whitetail. My goal is to get as close as possible and give them a trial run or two.
It is my belief that there is a similar, yet lower weight combination that would serve readily for the 150-200 lb animals with lighter bone structure.
While Dr. Ashby’s report is unbelievably helpful, the laws of physics indicate that somewhere in that EFOC range a slightly lighter arrow may perform within the same desired results the report shows when used on our common and much smaller whitetail.
I am, in no way, disputing the report but hoping to add to it doing similar tests (in the FOC and arrow weight areas)and report them to this thread for Doc and others to use…….or not.
Within any testing, there are variables.
My testing will just be smaller yet similar with the advantage of having Dr. Ashby’s findings on the BIG animals as pertinent information.
God willing, I hope to test a couple bow weight/arrow weight combos as well with the help of a close freind.
It is my opinion that this study will be on going and not just THIS SEASON so I am just attmepting to add what info I can as I hunt deer in the midwest.
David PetersenMemberJuly 4, 2009 at 10:48 pmPost count: 2749
Clay — look up at the top dark green bar for Ashby Library. Click on that and you’ll see another link to the FoC easy calculation chart (I’ll ask Robin if it’s possible to get a direct link of its own so it’s not so hidden) — no math necessary, just a couple of ruler measurements. Double-check your FoC, remind us what weight bow you’re shooting and whether wood (slow) or glass, carbon, etc.
Good stuff Steve. While some are complaining that we of the Ashby persuasion are troubling the minds of inexperienced archers “with stuff they don’t need to worry about,” I counter that anyone who’s trying to kill our fellow creatures in an ethical way had damnwell better worry about getting it right! So you can hardly “over obsess” with this stuff. Besides, thinking, like real hunting, is fun once you get used to the pain, eh?! 😈 My experience agrees with yours — that it’s easier to increase FoC with lighter shafts, and that EFoC on lighter shafts, all else equal, gives more penetration than normal FoC on heavier shafts … just so we don’t drop below What Ed tells us is minimal overall weight for all big game esp. from lighter, slower bows, 650 grains. My current elk rig is 680 grains with EFoC, selected over 750 grains with high FoC due to consistently better peneteration in foam. In recent years I’ve been carrying a selection of excellent arrow setup choices so that whichever one I wind up killing an elk with, I’ll be able to shoot at least four different combos into the fresh warm animal’s scapula. I never ever want to say “What went wrong?” again when I hear that horrid bone-hit sound and see the arrow bounce back or fall out with insignificant penetration as the animal runs away. Time now for Mex beer, American hamburgers, and Chinese fireworks. dave
Clay HayesMemberMemberJuly 5, 2009 at 12:23 amPost count: 418
I dug through my shaft stash today and pulled out a couple in the 65# range. I made a 260 gr. field tip by grinding a taper onto a 125gr. field point and fitting it into a 160. It doesn’t look bad and, if after some more testing they work out, I think I could do a very light weld and fuse them permanatly. If the above works out I think I could spot weld the modified 125s into a 160 grizzly without messing up the temper. We’ll see.
The 65# shafts with 260gr tip shot well enough without fletching, so I’m fethering some up now. The arrow will come out to around 17% FoC and weigh around 720gr. If I try to increase FoC any more, I’ll have to go to a higher spine wt. which I don’t have at this moment.
I’m shooting a 60# osage self bow, 28in draw.
Steve Sr.July 5, 2009 at 1:02 pmPost count: 344
I also tried internal footing via drilling and inserting nails, but the added weight was nowhere near enough.
To eliminate duplicated trials, what size of internal footing hole has been tried and filled with what?
Too much of an inquiring mind here.
I’m at a loss as to WHY such would not be possilbe. Bear with me here, my freind. Perhaps I can help.
If you can, also give me HOW MUCH grain weight you were looking to add in the internal footing. A rough, even high rough estimate is acceptable.
Steve Sr.July 5, 2009 at 2:16 pmPost count: 344
In the process of some things here in the next couple weeks but keep in mind that tungsten is 1.7 x the weight of lead per chosen unit.
Another factor is the weight’s location. The further from the fulcrum or balance point, (since the factors involved here do use the same calculations as for a “lever”), the greather the change in the FOC.
This applies to both ends. Using my 29 inch arrow as an example a 20 precent FOC is 5.8 inches forward of shaft center.
That gives me 14.5 + 5.8 or 20.3 inches of “lever” on the nock end and 14.5 – 5.8 or 8.7 inches of lever on the tip end.
Should I have an arrow OVER the, for now, targeted 650 grains, REMOVING 10 grains of weight on the nock end equats to 2.3 times as much or 23 grains ADDED on the head end and will effect the FOC roughly the same.
Again, those calculations are using the ENTIRE length of each lever. Actual changes will differ slightly( be less)since we are not able to add or remove weight exactly on the ends.
Sorry…..thinking out loud again.
EFOC should be obtainable, IMHO. I guess I’ll find out. The MEANS of which they are reached may be radical and TOO radical for some but the information should give each a few choices to decide upon using.
More later. Sorry if Im stepping on toes. I’m not meaning to.
Look up “uncouth” online, there is probably a photo of me there. 😆
David PetersenMemberJuly 5, 2009 at 4:59 pmPost count: 2749
I agree that tungsten is the way to go. O.L. Adcock uses it and though I’d had a nip that night I seem to recall him saying he hadn’t broken off a head with it yet. He showed me a skinny rod of the stuff and it’s amazingly heavy and adds strength back to the drilled-out shaft tip, where soft lead does not. He uses a clever little homemade wood guide to get the drilling perfectly centered every time. I’d expect some arrow makers to start offering these soon, as they would be cheaper and offer more FoC than footed shafts. I I guess you could drill and wire a footed shaft as well.
Clay HayesMemberMemberJuly 5, 2009 at 10:56 pmPost count: 418
What I ment to say is that lead is much heavier than steel, not tungsten.
Anyways, where does a fella find a tungsten rod if he did want to try it? Also, how big a piece would it take to get 100 or 200gr? For instance, at 1/8in, how long would it need to be to weigh 100 gr.
Steve Sr.July 5, 2009 at 11:30 pmPost count: 344
The tungsten I saw online was 1/8 inch and 8.5 inches long. Each piece was 1.15 ounces or 503 grains. (437.5 grs / oz)
So, one inch of 1/8 inch tungsten (at least that what I saw) would weigh just over 59 grains.
If your not in a huge rush, hang on and Ill see if I can get some. Ive some questions in to them on how rigid those were.
I wont need lots since one rod will do 3 or 4 arrows. I should be able to forward some out to a few guys wanting to try that.
I dont think any of us want several feet of this..or maybe you do. lol
Ill let you know what I found out and maybe O.L. will tell David his source.
Mark TurtonJuly 6, 2009 at 1:20 pmPost count: 759
I’m sat here looking at about 2 tons of TC rod let me know what you want to try, smallest diameter ground rod I have is 1/8″ or 2.0 mm. in length 310 mm. I will bring in some grain scales tomorrow and give you some weights, just spotted Dia. 2.0 x 100 mm.
You may be better trying TC round balls or even lead shot as it would be easier to adjust the weight, to cut TC accurately you will need a diamond slitting disc although you may try a diamond file from an engineer’s shop, score it deeply and just snap small diameter stuff, not very scientific.
Alternatively how about TC washers, I’ve used steel behind screw ins? Would have to get these made to order approx 6 weeks at present.
Food for thought, Mark.
Ed AshbyMemberJuly 11, 2009 at 3:10 pmPost count: 816
I’ll ‘speculate’ that Dave is having problems with the shaft breaking at the point where the woody weight and shaft join. Why? Increasing the length of the ‘rigid structure’ creates a longer lever arm for the force. On an angular impact that would mean an increase in the applied force at the point where the rigid structure and the shaft meet.
‘Externally footing’ a shaft with a section of aluminum has somewhat the same effect, but the section of aluminum shaft would show a bit more flex, compared to the more rigid woody weight. Also, the longer such an aluminum shaft section external footing was, the more flex it would exhibit (at a given applied amount of oblique force).
I had this same ‘problem set’ when trying to work out the internal footing system to strengthen the carbon shafts. Adding a simple dowel inside the carbon shaft made them stronger on direct impact shots, but on angular impact it simply moved the weak point further back along the shaft, and did appear to increase the angular-impact shaft breakage rate somewhat. That’s what led to the graduated-flex internal footing design.
David PetersenMemberJuly 17, 2009 at 7:32 pmPost count: 2749
Clay Hayes wrote: Dave,
In your testing of woodie weights, what broke? was it the shaft or did the impact cause the BH to seperate from the weight?
Clay — Sorry for the delay in responding. Both — that is, I had separation of the field point from the woodyweight, and I also had enhanced incidence of shaft breakage behind the head due to the longer “lever arm” and torque of the double-length head on angled impact with a hard target. I must assume until proven otherwise that both these issues would perhaps be even worse with a broadhead because it’s longer and “catches” the target material more abruptly on impact. But remember, I was trying to make this happen so was doing comparison shooting at a consistent angle of about 30 degrees into a big old ponderosa pine with thick bark to provide some cushion. So long as shots are straight in, if you get a good glue joint between head and WW (I wound up using epoxy after several failures with hotmelt), I saw no difference in my admittedly amateurish test shots. But then, we are working to build arrow systems for just those “wabby-sabby” occassions when things are less than perfect. I’ve totally abandoned WoodyWeights, but that doesn’t mean others can’t make them work. Thing is, as good broadheads increasingly come available in ever-heavier weights, with field points to match, why not use those rather than a lighter head and a WW? Restated: I’m uncomfy with adding another potentially weak link to the arrow system. The tungsten rod, because it’s stiff, sounds like the ticket at this point, since it adds notable weight and strength where it’s most needed as well. And I doubt, per unit, if it costs more than WWs. My 1 cent. dave
David PetersenMemberAugust 22, 2009 at 6:55 pmPost count: 2749
Clay — check out the Tusker Condords at 190 grains, nice single bevels, good steel, highly recommended by Sharpster and about the same price as any standard head. The main reason the ABS Ashby is 320 grains is that it comes with a steel insert. dave
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