THE WEAK LINK

[mhay]

#2810

I’ve been thinking on this problem for some time . It realy hit home as I was building front end of my arrow with the STEEL broadhead adapter , and STEEL broadhead. That aluminum insert sucks.

Then in my post yesterday about PLAYIN’W/FOC , Mr. Petersen stepped in with his thoughts and mentioned the weak link . His comments got me to thinking again . So , I pulled a broadhead off the shaft ,,,,,dug out a new aluminum insert .Here’s what I found .

I.D. of insert at the shank area of BH adapter = .204 inch.

O.D. of adapter shank,,,,,,,,,,,,,,,,,,,,,,,,,,= .196 inch.

Is it the unsupportered space between the insert wall and the shank of the adapter causing the weakness?

Is it the simple fact that the insert is too short ?

Or a combination of both and the insert being aluminum ?

What do you think ,,,,,or know ?

[Vintage Archer]

#13279

mhay wrote: I’ve been thinking on this problem for some time . It realy hit home as I was building front end of my arrow with the STEEL broadhead adapter , and STEEL broadhead. That aluminum insert sucks.

Then in my post yesterday about PLAYIN’W/FOC , Mr. Petersen stepped in with his thoughts and mentioned the weak link . His comments got me to thinking again . So , I pulled a broadhead off the shaft ,,,,,dug out a new aluminum insert .Here’s what I found .

I.D. of insert at the shank area of BH adapter = .204 inch.

O.D. of adapter shank,,,,,,,,,,,,,,,,,,,,,,,,,,= .196 inch.

Is it the unsupportered space between the insert wall and the shank of the adapter causing the weakness?

Is it the simple fact that the insert is too short ?

Or a combination of both and the insert being aluminum ?

What do you think ,,,,,or know ?

mhay

Bent adapters is not isolated to aluminum .Some have experienced the same problem with steel. Bending of steel adapters is generally associated with heavy arrows (750 grn +) hitting large bones. I do not know what the actual cause is as I have been doing tests and can not duplicate the bending of steel adapters.

I beginning to think that upon impact of the broadhead that the adapter thread make up with the insert is jarred enough to break it loose and create a small gap which allows it to bend …..Just a theory as I have not been able to duplicate it.

I do not recommend a aluminum inserts as they are to soft and really prone to bending. (for what ever reason that causes it)

For most hunting in the USA a steel adaptor of 100grn or 125 grn would be my choice. These are still not fool proof.

Bending of the adapter upon impact more than likely will hinder,slow, or retard good penetration.It is important to try and bomb proof the WEAK LINK AREA

For large game such as moose and buffalo or large african game I believe titanium adapters with a extended adapter (part that fits in 5 degree taper.)should be used. Grade 5 titanium has twice the tensile strength as steel.The reason I say it should have a long taper is there are some titanium adapters that have short tapers similar to the 75 grn steel adapter and other aluminum

adapters. Until someone can isolate the reason for bending I would stay away from short tapered adapters.

There is an other alternative to the screw on adapter and that is a adapter/insert combination. This option eliminates the threads and any potential gap between the broad head and arrow.I have no reports of this alternative creating problems. For large game the adapter/insert and a footed arrow would eliminate most potential problems.

This bending problem is not just isolated to glue on broad heads with adapters.It is also happens to broadheads that have the threads built into the head,

which should lead to some conclusion???????

I hope some one can shed some light:idea: on this problem as it is driving me up the wall:D

[David Coulter]

#13347

Okay, just a guess on my part, as I’m not a machinist or scientist. Any time you great a link or a joint it’s a potential place for a malfunction. Probably you could eliminate this by building a one piece adapter/insert to glue into the shaft and into the broadhead. Of course there would have to be a lot of combinations to match diameters and weights.

Overall, I’d say good luck at building something that can fly right and never, ever break. You’re doing a heck of a job eliminating almost all of the problem as it is.

My two cents. dwcphoto

[mhay]

#13354

Thank you MR. FURLONG ,

I appreciate your responce with such detail and thought .

I’m actually wondering if a ”REAL” fool proof arrow can be made . That is , and stay within desirable FOC , and arrow weight , and good velocity , without occassionally bending an arrow or insert or both .

I shot at a squirrel . I pulled the shot and clipped a 1 inch sassafrass sapling with the ”HAMMER” blunt . It ruined the shaft . Point being , that a 688 grain arrow from 51# , @ 152 fps was ruined . What about an arrow at more velocity and greater FOC hitting the radius of a rib or a shoulder blade .

I realize there are so many possibilties that can happen when an arrow strikes the target , it makes me wonder if there will ever be a ”REAL’ cure for this problem .

[Vintage Archer]

#13409

dwcphoto wrote: Okay, just a guess on my part, as I’m not a machinist or scientist. Any time you great a link or a joint it’s a potential place for a malfunction. Probably you could eliminate this by building a one piece adapter/insert to glue into the shaft and into the broadhead. Of course there would have to be a lot of combinations to match diameters and weights.

Overall, I’d say good luck at building something that can fly right and never, ever break. You’re doing a heck of a job eliminating almost all of the problem as it is.

My two cents. dwcphoto

David

TuffHead offers the adapter/insert in one piece you can see them at

http://www.vintagearcheryco.com/shop/ they are down in about the middle of that page.

You are right it takes many different sizes to fit different arrows and to offer different weights within those sizes.

Like you say maybe everything is being done that can be done to eliminate the WEAK POINT.

[Vintage Archer]

#13420

mhay wrote: Thank you MR. FURLONG ,

I appreciate your responce with such detail and thought .

I’m actually wondering if a ”REAL” fool proof arrow can be made . That is , and stay within desirable FOC , and arrow weight , and good velocity , without occassionally bending an arrow or insert or both .

I shot at a squirrel . I pulled the shot and clipped a 1 inch sassafrass sapling with the ”HAMMER” blunt . It ruined the shaft . Point being , that a 688 grain arrow from 51# , @ 152 fps was ruined . What about an arrow at more velocity and greater FOC hitting the radius of a rib or a shoulder blade .

I realize there are so many possibilties that can happen when an arrow strikes the target , it makes me wonder if there will ever be a ”REAL’ cure for this problem .

MHAY

I think you are probably right…. A perfect arrow, as we know it,may hit a bone at a weird angle and react differently than if it hit the bone straight on. It is hard to eliminate all the problems that can occur with the hunting arrow, but a lot of fun trying:D:D

[James Harvey]

#13451

Joe,

I think it was on one of the youtube videos you guys posted from Ashby’s 2012 Kalamazoo seminar that I remember him saying that as far structural integrity is concerned, strong wooden shafts performed best. Do you remember if that is correct?

Jim

[Stephen Graf]

#13733

This is somewhat before my time, so maybe I wasn’t interpreting the picture correctly, but I have seen video of the early screw in points from Bear Archery on some of the old Bear movies. These may be the “answer”

Instead of an #8 threaded shaft used to connect the point to the arrow, it appeared to be closer to the diameter of the arrow. at least a 1/4-32 or maybe even 5/16’s or so. I don’t know what was left to cut threads into in the shaft, but the threaded end of the point sure was big.

I’ve never had an aluminum broadhead insert fail. But I have had 4 or 5 steel ones bend. They always bend in the same place – the shoulder of the threaded part bends.

Joe – The last one that bent was my last little trip in Hawaii when I shot a little piggy. I’d be happy to send that insert to you for analysis (if I can find it). It may be a little bloody 😯

[Vintage Archer]

#13905

ausjim wrote: Joe,

I think it was on one of the youtube videos you guys posted from Ashby’s 2012 Kalamazoo seminar that I remember him saying that as far structural integrity is concerned, strong wooden shafts performed best. Do you remember if that is correct?

Jim

JIM

I did not remember that exact quote. I went back and checked the tapes and found where he discusses damage rates of arrows and he shows graphs where the damage rate of wood arrows is considerably less than carbon and aluminum. He included as damage every thing associate with the hunting arrow.

.The damage on aluminum and carbon on his graphs are proportionately much higher than wood.Test were made on dead animals shooting at the shoulder .This is a link to that discussion

http://www.tuffhead.com/education/kalamazoo%20jan%202012.html

Jim your study of Ashby’s works is showing through,nice job.:D

[Vintage Archer]

#13920

Steve Graf wrote: This is somewhat before my time, so maybe I wasn’t interpreting the picture correctly, but I have seen video of the early screw in points from Bear Archery on some of the old Bear movies. These may be the “answer”

Instead of an #8 threaded shaft used to connect the point to the arrow, it appeared to be closer to the diameter of the arrow. at least a 1/4-32 or maybe even 5/16’s or so. I don’t know what was left to cut threads into in the shaft, but the threaded end of the point sure was big.

I’ve never had an aluminum broadhead insert fail. But I have had 4 or 5 steel ones bend. They always bend in the same place – the shoulder of the threaded part bends.

Joe – The last one that bent was my last little trip in Hawaii when I shot a little piggy. I’d be happy to send that insert to you for analysis (if I can find it). It may be a little bloody 😯

STEVE

I have samples of bent steel adapters Thanks for the offer! They are all bent as you describe.:(

Do you recall when you retrieved your arrow if there was any sign the adapter loosened at the insert joint?

How heavy of a arrow were you using and how much wt forward. Just curious.

I am surprised about your experience with aluminums.I don’t,know what to think about that.Kind of throws another variable into the pile.

Your observations of the vintage head is interesting. It would be almost impossible to use a heavier threaded section now as arrow adapters especially with skinny arrows would not except a bigger thread.

Steve thanks for your input

[Vintage Archer]

#13932

There has been another discussion of this subject “weak link” on tradbow on the Friends of FOC I think it is titled “bent steel adapters” or something like that. That link is below.

https://www.tradbow.com/members/cfmbb/messages.cfm?threadid=1570CF95-1422-1DE9-ED3A567585989435

[Stephen Graf]

#14893

vintage archer wrote:

Do you recall when you retrieved your arrow if there was any sign the adapter loosened at the insert joint?

How heavy of a arrow were you using and how much wt forward. Just curious.

No way. After it happened the first time, I have always made sure there was no way the arrow would loosen (a loose broadhead seemed like the most likely cause). And I have studied the results when the insert bent, every time. What I have found is that:

1. The broadhead is undamaged

2. The shoulder of the insert is stretched an narrowed on the tension side of the bend.

3. The bend is in line with the plane of the broadhead.

I haven’t mic’d any inserts, but I wonder if the shoulder of the steel adapters is more narrow than aluminum adapters?

I have noticed that the relief between the body of the adapter and the shoulder is 90 Deg on steel adapters and 45 deg on aluminum adapters. I am sure this is a weight reducing measure. But it also reduces the strength of the steel adapters.

My guess is the problem is a combination of poor geometry and low carbon steel.

Arrow wt about 680 grn, FOC about 22%

[mhay]

#14911

Steve , I did in fact measure the inside of the insert and the shank of the steel adapter . Increments are in my first post .

I believe this is one of the major problems . I may be wrong .

I was looking closely at the alum. insert ,threaded onto the steel adapter ,,,,not tight ,,not snug ,,,,maybe .010 inch between alum. and steel . It seems to me that even though it were tightened and hit at even the slightest of ODD angle or radiused surface the steel could/would flex ,and once it starts it simply is magnified by a heavy shaft. ???????????

What would help ,,,in my opinion,,,would be a tapered hole in the insert ,no matter what metal it is made of. A tapered shank on the adapter would of course mate up with the insert and eliminate the flex .

I am considering filling the unsupported area with hot melt glue .

[David Petersen]

#15104

This is a really interesting discussion and I wish Ed Ashby could wade in with his experience and thoughts (apparently still laid up from most recent surgery). I have never experienced any such problems, so far as I can recall. I’ve broken and bent broadheads (the old-school thinner softer variety). With wood shafts of course I’ve had many breaks behind the head. And with carbon in a couple of cases the insert has broken out of the side of the shaft end, that is the carbon failed, though insert and head remained undamaged. From a purely amateurish “engineering” point of view it seems really strange that even a soft steel threaded shank would bend before the carbon that holds it would split. The whole idea, top to bottom, for encouraging folks to follow Ashby’s study findings is to do all we can to totally eliminate equipment failure as a source of wounded and lost game. So to have manufacturers of these components selling suppliers lame cheap steel for a primary component is absolutely unacceptable. I would love to see 3Rivers and all such do some serious stress testing on the internals they are being sold and in turn selling to us, and be able to offer some assurance of adequate steel quality and hardness that we can trust.

[Vintage Archer]

#15487

I had a chance today to measure adapters made from steel,aluminum,stainless steel and titanium.Most likely all made by different manufactures .?? I do not know the source these were adapters that I have accumulated over time

1. The shanks all measured .200 plus or minus .002 .Not much variation probably not enough to make one stronger or weaker than the other.

2 There was a variance of about 1/32 inch in length of the threads.Probably would not make a difference as long as the adapter was screwed in tite

3 As close as I could measure the shanks were within .005 of each other in length. Don’t really think this would be a factor in bending.

Open for more ideas !!!!:?::?::?:

[David Petersen]

#15519

Is it possible the adapter’s that have bent weren’t screwed in tight?

[Stephen Graf]

#16012

The yield strength of 6061 T6 Aluminum is very close to that of low carbon steel. It can be higher than some mild steels. 6061 T6 is the most commonly machined alloy for archery equipment.

There are even stronger aluminum’s that could be used for broadhead inserts.

With that said Check out this link, especially the section on impact hardness…

http://www.aldonco.com/Portals/0/docs/AlumvsSteel.pdf

I don’t know if what it claims about impact hardness is true or not (it’s claim 6061T6 is the strongest alloy is false), but it seems true to me, and comports with my experience.

The yield strength of steel actually changes as it is stressed. The more it gets bent, the harder it gets… So when the yield strength of steel is talked about, they talk about the 2% yield point, or something like that. Meaning what is the YS after it has yielded 2%. After that point, it becomes a constant value up to it’s ultimate yield point. I’m digging deep into the dark reaches of days past, so I may not have it all correct here…

Bottom line is that if the steel adapters are not heat treated after manufacture, they could well be weaker than a run-o-the-mill 6061 T6 insert.

Heat treating is cheap and easy. 3Rivers and others should ask their manufacturer to heat treat steel inserts.

[bobtieken]

#16385

I shoot CE Heritage 350’s out of a 65# recurve. My finished arrows weigh just over 800 gr. with velocity 140-145 fps. I use 100gr. brass glue on/glue in adapters and 160 gr, field points,. Both adapter and point glued in with 5 minute epoxy. If I hit steel, it will bend/break the adapter. I’m thinking of abandoning the weight tube, using JB Weld, and epoxying a 100 gr .243 bullet behind the brass BH adapter.

[Troy Warner]

#16490

bobtieken wrote: I shoot CE Heritage 350’s out of a 65# recurve. My finished arrows weigh just over 800 gr. with velocity 140-145 fps. I use 100gr. brass glue on/glue in adapters and 160 gr, field points,. Both adapter and point glued in with 5 minute epoxy. If I hit steel, it will bend/break the adapter. I’m thinking of abandoning the weight tube, using JB Weld, and epoxying a 100 gr .243 bullet behind the brass BH adapter.

Bob,

If you want to add more FOC I’d drop the weight tube and use a 275 gran field point. Then pick a broad head that matches the weight of your field point. Just my opinion. Others here may have better suggestions.

Good luck

Troy

[Munsterman]

#17371

Steve Graf wrote:

Heat treating is cheap and easy. 3Rivers and others should ask their manufacturer to heat treat steel inserts.

Sorry to post when I have a differing opinion ( as I don’t post much), but as a machinist and someone who works with steel and aluminum, etc. all the time , I felt I’d chime in.

Heat treating isn’t cheap or easy at all. In fact, it can add quite a bit of expense. Let me explain… not all steels are readily heat-treatable and some use more or less expensive methods of heat treat. So from a purely economic value, the possibility of using more expensive steels, adding heat treating ( shipping, another operation and the handling, too); de-scaling after heat treat and the inevitable loss of some parts due to deformation of heat treat would no doubt raise the price per unit quite a bit. The simple fact of the matter is, no one wants to pay what it’s actually worth to build such an adapter. I’ll grant you the guys here might, but let’s face it, we represent an infinitesimally small cross section of the market for inserts.

Years ago, I made some adaptors out of pre- heat treated 4140 CM steel. These weren’t screw-ins, rather a sleeve going into a 5 deg. taper. The pre-heat treat steel was only about 30 Rc. They were heavy and damn near indestructible ! Actually I don’t ever remembering damaging one, the shaft would always be what suffered damage. I used them on my stump shooting arrows with Judos. Point being, I’m sure there’s not a huge market for such an insert and therefore the cost would be sky-high.

I’ll post a pic if I can find one of them.

[Vintage Archer]

#17391

Great response! Good input!

DAVE: Steve had mentioned that his broad head and adapter were tight against the arrow insert. That was also was my observation after hitting a White Tail high from a tree stand .The arrow hit bone the adapter was bent,the broad head and adapter were tight in the insert,and the buck went on doing what bucks do during the rut.:D.Your thought was logical but evidently not true in all bent adapter experiences.

STEVE and MUNSTERMAN Hardness probably is a contributing factor I agree with Munsterman hardening of adapters probably won’t get done .

The other question is how hard is desirable .To hard the adapter might break instead of bending.:(

[mhay]

#17523

I wonder if anyone has tried making a one piece broadhead adapter / shaft insert from LEXAN ?

I worked in the plastic manufacturing business for 28 years . Though I don’t have training in PHENOLICS , other than setting up the molds which mold the parts , I can say that LEXAN is one super tough and lightweight material . Am told it is the bullet proof canopy on at least some of the older fighter jets .

Watched a co-worker beat on a piece what was 1 inch thick and 6 inches square with a 6 pound sledgehammer . He soon was winded in his vain attempt to damage the LEXAN .

May be wrong but I’m thinking it’s light weight would allow a lengthy portion to be inside aluminum or carbon shafts , and maybe a sleeve over wood .

It can also be molded to the specific sizes a lot cheeper than machining.

Anyone here have anthing to add ?

[Stephen Graf]

#18247

vintage archer wrote: …STEVE and MUNSTERMAN Hardness probably is a contributing factor I agree with Munsterman hardening of adapters probably won’t get done…

Cost is relative. In small batches, I agree that the cost would probably be prohibitive. But in larger batches, it may not be. If I was in the business of selling inserts, I’d make a few phone calls, just to see. It doesn’t cost anything to ask: “where is your price break?”

I did a quick google search and found a couple shops offering a $75 min batch charge. For a 5000 part run, that’s about 1.5 cents/part (assuming that 5000 parts would be a minimum batch run). Plus shipping.

My experience with getting parts made is that it is cheaper to machine soft metal and then heat treat it, than it is to machine hard metal.

But like you say, there is always more than one way to skin a cat. What about a composite insert? Fill the end of an aluminum insert with lead? Get the weight of the steel inserts with the durability of the aluminum inserts…

I bet there is a community college near you that has the equipment to do a bending test on aluminum and steel inserts to definitively determine which is stronger…

[Munsterman]

#18384

Steve Graf wrote: [quote=vintage archer]…STEVE and MUNSTERMAN Hardness probably is a contributing factor I agree with Munsterman hardening of adapters probably won’t get done…

Cost is relative. In small batches, I agree that the cost would probably be prohibitive. But in larger batches, it may not be. If I was in the business of selling inserts, I’d make a few phone calls, just to see. It doesn’t cost anything to ask: “where is your price break?”

I did a quick google search and found a couple shops offering a $75 min batch charge. For a 5000 part run, that’s about 1.5 cents/part (assuming that 5000 parts would be a minimum batch run). Plus shipping.

My experience with getting parts made is that it is cheaper to machine soft metal and then heat treat it, than it is to machine hard metal.

But like you say, there is always more than one way to skin a cat. What about a composite insert? Fill the end of an aluminum insert with lead? Get the weight of the steel inserts with the durability of the aluminum inserts…

I bet there is a community college near you that has the equipment to do a bending test on aluminum and steel inserts to definitively determine which is stronger…

$75 min batch charge is actually quite reasonable, but what they’re saying is they won’t do anything for less than $75. That means bring them one insert, it’s $75 ( at least). The reality is that something like this would likely add somewhere in the $.30 -$.50 per piece. The correct way to do this would be to heat treat the stock first and then turn it in the heat treated condition ( very do-able if not made too hard, which you wouldn’t want to anyway). Bottom line still is cost… most inserts are likely made from 1018 – not something that takes well to heat treat, so now you’re left using different (more expensive) steel.

The fact of the matter is, I believe you could build inserts to withstand the type of punishment we’re talking about, far more than aluminum would anyway, however, you will wind up shifting the “weak link” to another part of the arrow. In this case, likely the shaft just in back of the insert. Now you have to look at footings or other ways of distributing the stresses over a greater area of the shaft so that we don’t exceed the yield strength of the shaft at any given point. I believe this is why Mr. Ashby found a lower damage rate with wood than other types of shaft… woods ability to distribute these forces over a greater area (flex/or give at impact without breaking)as opposed to the “hinges” we create when joing the dis-similar items of shaft, insert, and point.

The above is one of the reasons I went with aluminum “outserts” on my son’s arrows. By tapering the aluminum over a great distance to a thin edge, I was able to prevent a “hinge” where shaft and internal insert met. (well, at least not as much of a hinge as I would have had with an insert that maintained full thickness/strength and then abruptly ended). The shaft actually extended up into the 5deg. point somewhat. So we had point,5deg ferrule and shaft tapering to tapered aluminum and shaft, to just shaft.Not perfect, but pretty decent. My son has stuck these in wood and bounced them off rocks at 3D’s and we’ve yet to have a break or bend at this point. He did have one that hit a large pile of rock that blew the nock off and shattered the shaft (carbon) slightly less than midway back and deformed the field point’s nose, but the attachment was ok.

I think this is what is needed… an insert/ point mounting system that is adequately strong and a means to distribute the force of impact over a greater area of the shaft. I believe Mr. Ashby accomplished this with tapered wood internal footings.

I also believe that heat treat or not, a 5deg. taper directly into a ferrule (inside like an insert or outside like an outsert) is a far better means of point attachment than the conventional screw-in type. – It’s just not as convenient.

I think Lexan/composite could have merit if it were adequately strong and accomplished distributing forces over a large area so things might give some but not break. This would likely mean a long insert. Expense? I don’t know – I’m not a plastics guy, but I bet composite might get pretty spendy.

[mhay]

#18412

I’m not computer savvy . I googled ”lexan” and came up with this ,,,,,Lexan-wikipedia free encyclopedia

Lexan is more amazing than I thought .

I’ll be looking into some prices .

[mhay]

#18500

Here’s a little more info on the LEXAN idea .

According to my ‘google noodle’ that rattles b’tween my ears , one could take a piece of lexan and machine it to the size needed to fully eliminate the aluminum shaft insert and the steel broadhead insert . And yet add strength and integrity to the shaft .

No doubt a solid piece acting as an internal footing would be too heavy (maybe,,,maybe not ). I see it better if it is too heavy thereby allowing a sort of ‘backboring’at a taper to lighten the material and yet still remain super tough and some flexiblity .

Here is s pricing form ePlastics.com .

Prices are for the .375 rod,,,,.250 is cheaper.

1-7 feet @ $2.23 / ft.

8-95 ft. @ 1.36 / ft.

96+ ft. @ 1.17 / ft.

machine grade lexan polycarbonate rods.

start @ .250” and follow in 1/8 inch increments to 1 inch .

I know , it’s more money and maching time on top of the assembly . But it may be the toughest arrow when finished , thereby saving money on ruined shafts .

It’s just an idea .

[mhay]

#19798

Ok,,, just got off the phone with eplastics , in californy. They no longer keep LEXAN in stock but it can still be ordered, which means it would have to be molded .

REP said they do have DELRIN in stock at the various sizes . The .375 rod is $1.20 per foot . I have heard of this material , but really do not know about it. REP said it’s tough like LEXAN . He could not give me a weight per foot .

I plan to order a foot or two in a couple days .

[Munsterman]

#19913

Rep wanted to sell you something! Delrin and Lexan are definitely NOT the same, nor particularly similar to my knowledge. Like I said, I’m not a plastics guy, but we have machined Delrin many times. You’ve probably seen delrin already… many of the “plastic” washers used in the assembly of treestands (to prevent squeaks and rattles)are made of Delrin. It’s a rather slippery plastic. We used to machine “runners” for conveyor lines from it. It’s reasonably tough, but relatively soft. Lexan is a polycarbonate- it’s tough, but relatively hard (by comparison).

[mhay]

#20842

Thanks Munsterman. I’d heard of delrin but have no experience with it . Guess I’ll have to keep looking for LEXAN .

[Munsterman]

#22194

mhay-

Didn’t want you to think I was trying to discourage you… If your going the plastic route, you may want to look at Nylatron. It’s a fiber-reinforced nylon product. Fairly hard, seems pretty tough, too. I’d actually spin you some inserts if we had bar stock (just to try), but the stuff we’re running uses 5/8″ sheets.

[mhay]

#22612

Munsterman,

I didn’t take your post as a discouragement.

I was able to locate some LEXAN rods . Will be ordering 4 ft. next week . I have a small lathe to turn the material .

I tried to find the weight of LEXAN per foot but no one had such info .

Found one place that made a 7 gram LEXAN projectile and fired it from some kind of air gun at 23,000 fps into an aluminum block . Impressive to say the least .

At this point the only downside I can find with this idea would be in the event of broadhead damage . Assembly will require some epoxy rather than regular hot melt glue . The LEXAN has a melting temperature of 270 degrees F . To remove a damaged broadhead without damaging the LEXAN insert could be a challenge in itself .

[mhay]

#35541

O.K. I received the 4 feet of LEXAN today .

According to my Pacific powder scale it weighs 35 grains per inch .

Just for fun ,,,a one piece broadhead adapter with a 4 inch internal footing (I’ll be using aluminum shafts),,with a 125 grain broadhead mounted , will be a little shy of 300 grains up front .

I’m not sure how much length is necessary in the FOOTING section . This material is stout and tough , yet allows a slight flexing , in 4 inch length. I think it will absorb a lot of shock and possibly give enough to prevent snapping or bending the shaft .

I realize I may have too high expectations for this project . But , like they say ” ya cain’t kill ’em from the couch”

Next step is to get some coaching from a real machinist so I don’t waste the material . I have the tooling but little experience .

[Ed Ashby]

#42575

I’m waiting to see how this works out. I tried a number of different materials, including some polymers, for both internal footings (back of brass inserts) and one-piece adaptor/insert/footings, but not Lexan. Polycarbonates are pretty tough, and should make a great internal footing material but I wonder about the rigidity at the adaptor’s taper, especially on an angular impact. Never found anything that worked as well as a hardwood IF back of a long brass adaptor/insert. With enough tinkering I hope you find one! Wood’s problem is the lack of uniformity; grain and density).

Ed

[stalkin4elk]

#42675

Some concerns of plastic are: 1)thermal expansion/contraction coefficients are very high. Shrinkage and expansion is possibly enough to separate glue joints with metal?? Lots of temp changes in a season here from sub-zero to hot.

2)Another concern is most plastic is brittle when cold and might be really bad at less than freezing temps.

3)Flexibility may help or hurt this application.

Ultra HIGH Molecular Weight plastics(UHMW) is another plastic option that is extremely strong and can handle impacts in the cold(snowmobile skis). It also must be machined because of its toughness(many high wear industrial components). Google UHMW plastic. Yes, it is expensive.

FWIW, I recently found Easton’s Deep Six shafts fit perfectly inside GT 75/95 shafts. Maybe an internal carbon footing option????

[mhay]

#42822

Well, I just finished turning out two , one piece adapters with 5 inch footing . One with 5 degree taper which is 1.375 ” in length . The other is drilled and tapped to accept the 250 grain HAMMER blunt , or 250 grain field point.

The tapered adapter alone weighs in at 130 grains . My 125 grain ACE broadhead actually tips the scale at 130 grains . Thus bring my total front end weight up to 260 grains. Sure to be a mite higher when epoxy is applied the full length of the footing . Total weight with the same broadhead , 125 gr. steel adapter and aluminum insert is 289 grains .

The drilled and tapped adapter weighs 105 grain and the HAMMER weighs correctly at 250, totalling 355 grains .

I will be testing with the HAMMER first . I do not want to ruin a perfectly good Ace broadhead . The HAMMER has those wicked , sharp hooks that should tell me something in short order . Recalling how I ruined an arrow ( bent behind aluminum adapter )when I clipped a one inch sassafrass sapling when shooting at a squirrel . I plan to shoot at a well seasoned piece of elm firewood , stood on its end , and aiming just inside the outer edge . I think this should give a substantial GLANCING shot .

I’ll go epoxy the drilled adapter in now and hopefully get in some shooting before this storm hits .

[mhay]

#42973

Test results:

1st shot at 15 yards ,,clipped the elm about 1 inch inside . Arrow went off line about 6 feet . Tore a chunk out of the elm . Arrow remained straight ,,,all is good.

2nd shot I evidently dropped my bow arm . Buried in the ground under the elm.

3rd shot I stepped up to about 7-8 yards . Drilled the elm dead center . Glue failed . Shaft cut the LEXAN shoulder and allowed shaft to continue foward into the Hammers backside , thereby letting the head and LEXAN go about 5/8ths inch into the shaft .

, splitting the shaft on two sides .

Time to rethink the gluing and the collar .

I ain’t givin’ up yet .

[OpenSky1]

#57394

More confirmation to same problem. 698 Gr., 32.8% FOC, 6.4 GPI Carbon Tech Cheetah 3D arrows into 3/4″ particle board. I varied shot distance and angle of impact. Arrows and BH(300 gr. Tuff-Head and 75 gr adapter)no fail. Field point and BH adapters failed in 2 of 4 arrows.

I did not buy adapters from Joe, as other sight showed an adapter with the nice shoulder discussed. Well I ordered and opened mail and lo and behold received something other than advertised. Called with inquiry and told adapters vary with the season…all suppliers gave same speech.

I would be better with a lighter BH and a solid adapter. Will try filling the void with epoxy to increase bond area and also try the titanium as recommended.

Pics attached to help clarify…forgive the scribble…hard to write with a mouse.

[David Petersen]

#57586

Good info, guys. It would appear that we/you have entered another world of demand on arrows. With the Tuffhead we have as close as we’ve ever had to a never-fail broadhead. But with a lot of arrow weight and a lot of FOC the impact momentum is so tremendous that current internals and shafts just can’t handle it … at least not into a tree or particle board. Thus, on a huge animal, elk or moose say, if you missed major bones you’d be assured of a pass-through. Direct or angled impact on a major bone joint, however, could blow up the internals and/or shaft. But I’d still take my chances on that over using a lighter setup.

You know, we’re making enough noise and recruiting enough folks to the “no such thing as overkill with arrows” as opposed to the old “If it works don’t fix it” that — as we clearly have seen with broadheads in the past very few years — the sharper manufacturers are paying attention. I predict that the near future will see stronger internals and carbon shafts being marketed. That’s the good news. Of course the technology will keep the price high, which is the downside. For me, whatever it takes to know that I left no stone unturned before releasing an arrow into an animal … if I can’t afford the most lethal arrow out there, I can’t afford to go hunting. Keep us posted.

[OpenSky1]

#57724

For me, whatever it takes to know that I left no stone unturned before releasing an arrow into an animal … if I can’t afford the most lethal arrow out there, I can’t afford to go hunting. Keep us posted.

Couldn’t say it better! The purpose to all this “madness”!

[Author]

Posts