The thread on spine/weight variations with wood shafts got me to thinking about the same issue with carbon shafts.
I know carbon shafts can be 10-15 grains different in weight, even though they might be marked +- 2 grains. This was explained to me that each batch was supposed to be within +- 2 grains, but shafts from a different batch could be outside that range. So if batches got mixed in the store, or if you mixed them yourself, you can't depend on the tolerance marked on the shaft.
I wonder if the same thing applies to spine? I'm not even sure how to test the spine of a carbon arrow. I know that VAP says their shafts come with nocks installed to match the spine grain, so evidently a carbon arrow's spine will change as you rotate the arrow, just like a wood arrow would.
I would imagine that by comparison with the variation in wood arrows, none of this makes much difference (I hope), but I wonder how much variation in spine and weight we're ignoring?
Probably would vary with different manufacturers products and which grade of shaft you purchase.
Instead of purchasing a spine tester I will shoot all the shafts bare shaft after I have tuned and cull any oddballs(don't get very many) as stumpers with fluflu. Weight has been pretty close.
Vast amounts in some cases even in the same dozen. I am right now shooting some Victory HVs that have in the best shaft 3# of variance from the stiff side to the weak side. The worst is 7#. The worst shaft I have is a CX with a baffling 11# variance. Easton and Carbon Tech have historically had the least variance by rotating the arrow for me. If you guys can wait til tonight I just got a brand spanking new set of Axis shafts that I will spine and weigh to show how matched... or usually mismatched your arrows will be.
Interested in what you find out about the AXIS shafts.
Most carbons are still made with the compound shooter (mech. release aid) in mind. I've done some tests when I was still shooting compounds, and I could shoot a 400 or 340 spine arrow (340 was just slightly heavier)and couldn't really tell a difference. Most tuning that we have to go thru, they don't.
I shoot Gold Tip XT Hunter black shafts. These are the more expensive straighter shafts. I spine test every shaft I get and separate them into like groups of .010" deflection. These are the only shafts I have experience with, and there is a great variance in spine, even in the same dz shafts.
I shoot 55/75 shafts which are marked .400 spine on the shafts by the mfgr. I have tested probably 30dz or more, and have yet to have one single shaft spine out at .400. They are all stiffer, and the range is from in the .340's to the .390's, with most being in the .360 - .380 range.
I spine every shaft and mark the stiffest side and index my nocks to that mark. On my GT shafts, it is not uncommon to see .010" - .020" deflection difference between the weak and stiff side of the shaft.
What spine testing has done for me is to reduce the number of "flyers" to almost none. I now always have groups of like spine arrows, and never have a .340-something arrow in the same quiver with a bunch of .370-something arrows acting all wierd!
Like I said above, these GT's are the only shafts I have experience with, so I don't know if other brands are like that or not.
My spine tester is a high dollar one (can't remember the brand) that is set up at 28" with a 1.94# weight.
Bisch
Slight variation in spine and weight doesn't surprise me much.
I am surprised that there is a weak and stiff side however.
I would think the process would be more uniform down the length of one shaft.
It is not. They are usually rolled from a sheet and then ground round creating a stiff side. Easton, Carbon Tech, PSE, and W&W have some sort of seamless wrapping on their shafts that mitigate that feature some. Manufacturers try to sell you on weight and straightness becaused its easy and cheap for them to control but spine consistency is far and away the most important aspect of an arrow.
I have several dozen Axis shafts in 500, 400 and 340. All are very close re physical weight, i.e. within two grains. I can feel a stiffer orientation to the spine on most of them when I roll them in my palm with one end of the shaft angled onto a hard surface. Haven't measured all the spines, but those I did were closely matched as well.
I'm with BISCH. I bought a spine tester last year cause I want to shoot more wood arrows. I have about a thousand carbons. I've tested most of the unwrapped ones. It did explain "flyers" for sure. There is definately a stiff side, and they spined heavier than expected. I was amazed at how many 400s were closer to 340-350. The weights were all close enough to not worry about within 3 grains I'd say on average.
Shafts I have had to adjust nock position the most to get spines equal from the same dozen were tapered carbon shafts. Love the concept of tapered shafts but it must be difficult to get consistency in manufacturing.
Ok guys, I just finished measuring a dozen Easton Axis 340s minty fresh and straight out of the tube. I was using a Flight Rite Pro set at 26" and I will list the spine in deflection rounded to .005 rather than poundage because in heavy weight shafts the scale is not correct. Again, I am using amo 26" with a 2 lb weight which will be different than what the factory uses.
Shaft 1 was .290, .300, and 326 grs.
Shaft 2 was .285, .290, and 327 grs.
Shaft 3 was .290, .290, and 327 grs.
Shaft 4 was .280, .290 and 324 grs.
Shaft 5 was .290, .300 and 326 grs.
Shaft 6 was .280, .290, and 326 grs.
Shaft 7 was .280, .285, and 326 grs.
Shaft 8 was .280, .290, and 327 grs.
Shaft 9 was .285, .290, and 326 grs
Shaft 10 was .290, .300, and 326 grs.
Shaft 11 was .280, .290, and 326 grs.
Shaft 12 was .290, .300, and 326 grs.
These readings are the stiff side, weak side, and weight.
I am actually a little shocked... that is the most tightly matched factory set I have measured. Those might be able to be perfectly matched by indexing the nock.
I also have 3 remaining Bloodsport 55/75 and they measure:
Shaft 1 .305, .310, 279 grs.
Shaft 2 .275, .285,278 grs.
Shaft 3 .285, 290, and 278 grs.
Those were bought per shaft out of a bin and you can see why those won't group well.
Those axis are really close! My GT shafts are way wider than that! Just like my GT's though, there is not a single .340 on the group!
Bisch
So, the next time someone tells me he shoots carbon because he finds wood shafts to variable, I'm going to kick him in the shins.
:knothead:
Guy
Bisch my Victory shafts were way wider than that to. Maybe somebody else has some axis shafts they can test to see if every batch is that close. I have never had carbons that close from a factory set.
:campfire:
Do you want the stiff side facing out or towards your rest?
Ideally you wany the stiff side toward your riser. Sometimes though you will have to index the shaft to tweak the spine. Of course that doesn't always work either which is why it is important that they match.
QuoteOriginally posted by bigbadjon:
Shaft 1 was .290, .300, and 326 grs.
Shaft 2 was .285, .290, and 327 grs.
Shaft 3 was .290, .290, and 327 grs.
Shaft 4 was .280, .290 and 324 grs.
Shaft 5 was .290, .300 and 326 grs.
Shaft 6 was .280, .290, and 326 grs.
Great info guys!! I shoot Axis 500 and 400 the most but don't have a spine tester yet. May have to invest in one?
I have been looking at this and need to ask a dumb question. Why two sets of decimal numbers ie: .290 , .300??
The spine of the arrow changes as you rotate the shaft. One reading is the stiff side and the other is the weak side. As I said in an earlier post depending on how the shaft is laminated it can make a huge difference.
Hey Bisch, I've got a home made tester i set up for woodies at 26" span & a 2# weight.... Do i have to remodel this to 28" and reduce my test weight to be accurate?.... i can post a picture of this ting if it will help.
I'm glad you said something because I put 28" in my post but have now corrected it. You can test it with the spine tester you already have it just won't give you the same read as the factory. It will tell you if they are matched. I had a conversion chart blown up into a poster and hung it at my work bench so I can easily switch from amo to Easton scale.
http://www.rangersarchery.com/sites/default/files/fileupload/Spine-deflection_chart.jpg
Here is a link to the chart I use.
QuoteOriginally posted by bigbadjon:
http://www.rangersarchery.com/sites/default/files/fileupload/Spine-deflection_chart.jpg
Here is a link to the chart I use.
Ok ... i think my spine tester is a bit back woods. It uses a protractor and gives me degrees of deflection that i convert with a different chart.
The numbers that show on your chart... lets take a 55# spine shows .47 & .57 on the easton tester. What do these numbers represent? Inches of deflection? or what?
Yes it is showing inches of deflection. This chart just adds the a row for the method Easton uses to spine shaft. So for the 340 shafts I just tested to be accurately marked they would need to read .280 on my tester.
Ok.... i get it... thanks.
Interesting stuff guys. Thanks for sharing and teaching.
Well, this explains why I don't shoot as well as I should. :)
But seriously, any suggestions for those of us who don't have access to a spine tester?
Well, this explains why I don't shoot as well as I should. :)
Beyond: You can do what Howard Hill did. Just shoot all your arrows and throw out those that consistently fly off track. However, probably won't work for two reasons. Most of us aren't that good/consistent of a shot to be able to do it, and 2, even though the spine and weight may vary some on carbons, or woodies (not so much on aluminums) the variations probably aren't enough to make much of a difference. Smaller differences than our own inconsistencies in shooting form cause. In short, small inconsistencies among a group of shafts aren't worth worrying about.
Orion speaks the truth.
If your draw is 1/2" shorter...
If your anchor moves 1/4" up or down...
If your release is a touch slow...
If your bow hand moves upon release...
There are infinite 'ifs', but the bottom line is that minor shaft inconsistencies can usually only be detected in the shooting of those who are extremely form-conscious and seldom vary in their technique. When I shot woodies I had to toss out the occasional weird arrow, and the problem was always traceable to bad spine or out-of-straight. I haven't had a carbon act that way for me ever, but I've only ever used Beman or Axis in identical configurations. I also used to require 5.5" HP fletching on my POC customs, but have even better flight using regular height 5.0" fletch on Axis customs.
Then there is also the unknowns of dynamic spine (deflection) vs static spine. It's one thing to know how a variety of shafts react to a 2# weight on a test unit, but quite another to prove what they do with 250 grains of broadhead in front and 60# of thrust behind them.
I was told of a fella (supposedly a World class shooter), that plugged both ends of his new shafts and threw them in a bath tub of water. Marked the stiff side accordingly. :dunno:
I knew some one was going to bring up dynamic spine. You must have matched static spine before anything else. if all of your arrows start with the same static spine then they will all have the same dynamic spine with identical length and components. Also plugging the ends of the shaft and floating them will tell you the stiff side but you won't know if they are matched in spine.
man, and to think I have been shooting carbons because of their "consistencies". Now i'll just say it is because of their durability.. ;)
So if you want consistent weight and spine, go aluminum?
If you want consistent weight and spine think like an Olympian. There's a lot more to the equation of good flight (consistency) than matched deflection in a dozen shafts. It starts there of course. Then again, what about the shaft's ability to maintain straightness through much shooting and perhaps some odd hits? Aluminum can bend and remain bent. Wood has the tendency toward memory when bent, which is why you can flex it and sometimes overcome a crooked shaft. You can also take a straight wood shaft and put a crook in it by flexing it repeatedly in the same direction. All shafting has its unique characteristics, and thus all is not equal.
I agree with the assertion that dynamic spine will match up (per dozen) as long as everything else is matched. The problem here is that dynamic spine (deflection) will be much affected by real-world factors such as the shooter's form and release, poundage (force) applied to the arrow, temperature, and other variables. Dynamic spine for the hunter inherently means a host of variables apply in actual use. In the end, we want an arrow which reacts well and with forgiveness...is not touchy or sensitive...to our errors.
I agree and matching your shafts is the number one way to achieve a forgiving arrow. How can you be sure of your form ,or anything else, if your arrows do not match? Another thing to moniter is that carbon shafts do eventually weaken to shooting fatique so you must also moniter that. Aluminum is the best shaft for tolerances off the shelf but carbon is longer lasting.
Just to see what I've been shooting, without trying to change anything, this is the range of weights and spines on six of the VAP arrows I've been shooting lately. As I mentioned, VAP states that they orient the nocks from the factory so they are aligned with the "grain" of the spine of the carbon arrow. I used the same static spine tester I use for wood arrows, with the nock openings facing up, since that's all I have. I don't have any bare shafts to test, so the weight differences could result from variations in the weight of the glue or fletching, I suppose, but that wouldn't account for the spine differences. To put it in perspective, the range of spines from 475-500 is the equivalent of 52-55# spined wood arrows, according to the scale on the spine tester. I suppose I'm okay with these variations, as they are probably way less than any variations I might introduce myself from shot to shot.
318 grains - 500 spine
314............500
317............475
315............485
316............475
314............485
I guess the real question has anyone started orienting shafts to match spine seen an improvement in shooting? That's the only way to know if it matters
I tried testing spines of different makes of carbon arrows, each being marked the same spine, and found that two of the three ran stiffer than marked, while one was right on.
Have you tried the same thing with aluminum, especially the X7 Eclipse shafts?
Interesting stuff, but the differences are so small I don't find it worth while to worry over.
Well i guess the bottom line is you only get out of this sport what you put into it... The closer your arrows are to being exactly the same is going to give your shooting ability more accuracy.......
So after you go through all this stuff and get everything just perfect.... then you have to accept that your shooting form sucks...LOL...
If you don't go though all this stuff you can blame it on arrow spine...
QuoteYou can do what Howard Hill did. Just shoot all your arrows and throw out those that consistently fly off track.
I've used this system for years and it's served me well.... But i've really had my eyes opened recently on the significance of bare shaft tuning. i think its definately worth while.
McDave,
Orient your nocks 90 degrees to emulate the force of the arrow and test your spine. That should be the same as the factory test for nock alignment.
Not sure how much difference it will make.
Mike
You're right Wingnut. I was trying to make it the equivalent of a wood arrow loaded with the grain vertical, and I guess my thinking was 90 degrees off.
This morning I went back and measured the spines on the same 6 arrows, rotating them 90 degrees as Wingnut suggested. The spines were very close to my first measurement. Since my spine tester only has marks about every 25 units, I can't give the actual differences, but I would say they are all within 5 spine units of the first spine measurement. Some were more, some were less, making me wonder if VAP really spends much time aligning the nocks, as they claim.
Ok how many wood shafts would you have to be spine test and weigh to get 12 near the same spine and weight? Mother nature varies a lot and someone must sit spine test and weigh long before they find a matched set. :thumbsup: blems) group and find I need to rotate my :banghead: nocks( most notable on bare shafts, stiff side vs weak side) to get the most constant flight. :archer2:
Generally you must buy about 100 shafts to hopefully get a matched dozen. This is of course variable due to the nature of wood. RMSG sells them already matched for about the price of a regular unmatched dozen as long as you like poc.
Is there reason to believe that the Full Metal Jacket Eastons may spine closer to specs than the Axis carbons, due to the aluminum outer?
I have some FMJs I can check for you when I get home this afternoon. I know that they have no variance by rotating the shaft.
Thanks! I sold all of my Goldtips off and found a good deal on a couple dozen FMJs and Axis Woodgrain. So far I like em.
That explains a lot of things to me about how I can make a wood arrow better than a carbon. Need to spend more time working the carbons. :campfire:
I just finished measuring those fmjs. They all tested .250 and as rotated the maximum variance on every shaft was .005. So that is right in line with the .300 listed on the shaft after conversion to Eastons scale. These shafts were FMJ DANGEROUS Game 300s.
Nice!
Interesting stuff guys thanks for the info! I shoot aluminums but, am set up to play with carbons too. This could come in handy.
Very educational. I went to the Easton site and spent some time reading about the various carbon and carbon/alloy shafts they offer. I came away understanding that some shaft types do have spine variances due to construction methods. Other shafts are made in ways which mitigate or nearly eliminate spine variations, and are consistent in spine despite nock rotation or orientation.
I wonder if there is an easy way to identify the 'correct' side of (example) Axis shafts without use of a spine tester...?
This thread is very interesting and very educational.
I do have a question and keep in mind I don't hunt with many compound guys to know if this effects them.
Question:
If carbon shafts are so inconsistent how does the average everyday compound shooter shoot such tight groups at 30-50 yards and beyond with them. My buddy this summer picked up a new compound and a dozen goldtip arrows. We set it up and sited it in. An hour later at 80 yards (with a range finder) he was putting 6 out of 6 into a coffee can lid.
I think 99% of compound shooters shoot carbon and can shoot fletch eating groups all day. Why would these inconsistency not effect them as much. Spine is spine, so their tuning capabilities should not matter?
Thanks again for this thread. I learned a lot from it.
Kevin,
Some claim you can put the raw shaft tip on a flat smooth surface and roll the shaft with your hand using the palm of the other hand to support the other end of the shaft. Supposedly, there is a "bump" felt on the stiff point. I never could get it...maybe my palms have been abused too much? :rolleyes:
Jason,
Shot you a note... we might impart a lot more variations wrapping around risers and shooting fingers where the string can roll differently shot-to-shot so that it's US that the carbon reacts to requiring us create more consistency in the shaft's reaction to our variables, whereby those "other" types don't have that to contend with? :dunno:
QuoteOriginally posted by LB_hntr:
If carbon shafts are so inconsistent how does the average everyday compound shooter shoot such tight groups at 30-50 yards and beyond with them.
I get the feeling that most of the people on this thread do not understand how miniscule the variances are. We're talking thousandths of an inch.
Comparing them to wood arrows is a little ridiculous.
As far as rolling the shafts to find the stiff and weak sides, I've never tried, because it doesn't matter with a trad bow. At Olympic distance I might rotate the nocks a little, but only if I have a bareshaft "flier." Rolling them is a waste of time IMO, because they act completely different coming out of a bow than they do laying on a table.
QuoteIf carbon shafts are so inconsistent how does the average everyday compound shooter shoot such tight groups at 30-50 yards and beyond with them.
I think shooting a drop away rest set at centershot with a mechanical release covers up spine problems to some degree so fieldpoint groups are good. You would also be amazed at the amount of compound guys that claim broadheads won't fly with fieldpoints, that it is impossible.
I did notice back in the wheel days that I got much tighter groups shooting fmj's and axis over the competitors carbon shafts.
We have to shoot around a riser and deal with finger torque and possible string roll. Does it really matter at the ranges we shoot? I don't know, but since I like to tinker so much, I think I'll find out.
http://tradgang.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=1;t=138019;p=1
Here is a thread I started on the same a while back.
I've found Carbon Express shafts to be the most consistent.
I'm guessing giff is so good it doesn't matter what he does with his arrows. For the rest of us matching you spine will instantly shrink your groups. Arrows of identical static spine on the jig will have identical dynamic spine when shot.
For guys like giff who think the difference is miniscule, I have measured as much as a 11# difference in spine on a quarter turn of a carbon shaft. This will instantly shrink your groups people.
For guys like giff who think this is a waste of time, I have measured as much as 11# of difference in a quarter turn of a carbon shaft. Shooting arrows like that make an archer look worse than he may be. I am not blowing smoke, this will instantly shrink your groups when every arrow flies the same. If you don't have a spine tester sell one of your bows and buy one.
Carbon Express Maximas are the only carbon I can find that are advertised with a tight (.0025) spine variation. Below is a link to a similar discussion I started a while back.
http://tradgang.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=1;t=138019;p=1
Using a spine tester is not necessary. Just shoot your arrows. If one doesn't group with the rest of them, twist the nock. If that doesn't fix it, throw it out. If you're shooting less than 50 yards or so, you probably won't notice anything.
BTW, I've never had to throw one out, and only had to rotate nocks twice in 6 years.
QuoteOriginally posted by bigbadjon:
I have measured as much as 11# of difference in a quarter turn of a carbon shaft.
That is not a problem with carbon arrows in general, it is just poor quality control. If I remember correctly from the first page, that was a CX, right? I've never had any problems with Easton.
Made In America. That's all I shoot.
Using a spine tester is not necessary. Just shoot your arrows. If one doesnt group with the rest of them, twist the nock. If that doesnt fix it, throw it out. If you're shooting less than 50 yards or so, you probably won't notice anything. :laughing:
Why is that so funny? There is no reason to go into a shooting session believing that your arrows are not consistent. Just shoot them. Don't fix what isn't broken. If one of them won't group, that's the time to start working on it.
Like I said before, they act completely different coming out of a bow than they do laying on a table.
The problem with dynamic spine is that it's almost impossible to measure and compare amongst shaft types. Dynamic spine is measurement of deflection via pressure (force) applied in line with the shaft.
Static spine is measurement of deflection via pressure (weight) applied at a 90 degree angle to the shaft.
I don't believe I've ever seen a standardized system for determining dynamic spine. I would tend to agree that...all things about the shot being equal...dynamic spine should match up well in arrows that have a closely matched static spine. Under actual dynamic stress (at the shot) I suspect that different carbon shafts behave differently, and some may have distinct advantages for the hunter.
In my opinion, if you see a lot of deflection difference from shaft to shaft, or even by rotating individual shafts, you have a massive quality control issue.
About 15 years ago I got a dozen carbon shafts and couldn't get them to tune consistently. When I finally put them on a spine tester what I found was that my dozen shafts were mislabeled. Half of them were the next spine group up. That was the last time I bought shafts from that manufacturer.
A few years later a buddy of mine bought three dozen high end carbon shafts from a manufacturer/retailer that hyped them up as the be-all end-all for traditional archery. He had huge tuning issues, so we weighed and spined each of his shafts. As I recall there was over a hundred grains of weight difference and .150 spread in deflection (about 17#). After quite a few conversations with the retailer and some persuasion from his credit card company, my friend eventually got his money back.
That being said, for the past 14 years my hunting arrows have been almost exclusively Beman ICS. Every time I get a dozen I check them for both spine and weight. I couldn't begin to tell how many dozens I've bought over the years—at least ten—and I've never seen the amount of variation some folks have posted about here. I can pick up any two I have, no matter if I bought them last year or 14 years ago, and they will weigh and spine the same.
For target archery my daughter and I have been shooting Victory VAPs and VX23s for the past couple years. I've never seen any weight or spine issues with them either. As a matter of fact, they are even tighter in tolerance than my Bemans, and that's saying a lot.
Last night, just for grins, I took two dozen Victory VX23s (my daughter's and mine) and checked them on my spine tester, rotating them each ¼ turn at a time. Out of those 48 measurements the high and low were only separated by .015" of deflection, or less than 2# of spine. I'll take that consistency any day.
Good info fellas, thank you. I've read similar comments about the Victory line. I picked up some CE Heritage shafts, as I've heard that CE has good quality control as well. They have proven to bareshaft easily, consistent flight, and group very well for me.. I don't own a spine tester to give you guys numbers, but suspect they are tight. They tuned as easy as my alums do.
Well, I spine tested 42 brand new Gold Tip XT Hunter 55/75 black shafts this morning. These are the more expensive .003 straightness shafts and are marked .400 on the factory label. As you can see from the following, I have still to yet find a single .400 spine arrow at all!
I came out with the following:
1 between .310 and .319
1 between .320 and .329
3 between .340 and .349
26 between .350 and .369 (I did not start counting until way into it when I got the first wacky one in the .310-.319 range)
11 between .370 and .379
If I had not spine tested these shafts, I know I would have been scratching my head trying to figure out what was wrong with that .310 arrow every time I shot it!
Bisch
Bisch,
Is that full length or cut?
I never used carbons, I wonder how consistent aluminums are?
QuoteOriginally posted by Chuck from Texas:
I never used carbons, I wonder how consistent aluminums are?
About as consistent as you can get, even from batch to batch, you can by 2 dozen and 1 year later by 2 more and they will match. This is what i have found anyway.
Dang it!!!
This thread is gonna make me buy a spine tester! Now I just gotta know.
Does a spine tester work on arrows already cut and fletched at 27" or can I only use it for future shafts?
QuoteOriginally posted by tzolk:
Bisch,
Is that full length or cut?
I spine test mine all full length. I only cut off 3/8" off of full length for my tune. I spine test them as I get them and put them in groups of .010" deflection, and then cut and make up a dz when needed out of the same group.
I have been shooting Gold Tips for a looooooooong time and have got the "recipe" figured out for them. Before I started using the spine tester I would have an occasional flyer that I had no reason why it was messed up. Most of the time I would just trash that arrow and go on. Now that I am always shooting like arrows, I almost never have any flyers.
I am also sorely disappointed in GT's quality control, as I get one or two of the waaaaaaaaay off shafts in every couple dz I test. And also, the fact that I still have such a wide range of usable arrows. To me, nearly$100/dz shafts should have tighter tolerance than what these do! I can shoot the .350's, the .360's, or the .370's with no noticeable difference in flight or penetration on animals. The stiffer ones do show a bit stiff when paper tuning, but because I have noticed no difference in my accuracy or in performance while hunting, I do not worry about it. I do wish they were more consistent though!
Bisch
LB: A spine tester will work on made up arrows. The results may be off just a little, but will help you identify any fliers. Traditionally, spine was measured by measuring the deflection when a 2# weight is hung on the shaft suspended between two posts 26 inches apart. The point and nock/fletches, represent a little weight on either end of the arrow, will affect the reading a little, but so little as to be of no practical significance.
For some reason, I believe it was Easton that began testing shafts with a 1.94# weight with the posts spread 28 inches apart. That became the standard used by most manufacturers of aluminum and carbon arrows. It does not give the same results as the previous method.
Of course, each method gives consistent results for that method, but the two are not comparable with each other. For example, a 50# spine using the 2# method yields a deflection of .52 inches. That same 50# gives a deflection of .61 using the 1.94# method, according to a conversion chart prepared by RangersArchery.com. When talking/comparing spine, it's important to know what measurement was used.
The most accurate testers give you the deflection in inches, hundredths of an inch actually. Some display the result in poundage of spine, usually not quite as precise.
Unlike LB hntr, this thread is making me NOT want to get a spine tester ha ha !!! Knowing myself, I'll obsess over any differences I find. Best to not know and just go by how they group. Since I ditched the Gold Tips and went to FMJs and Axis Trads, the unknown looks positive.
My spine tester is made by RAM Products. It is on 28" center and uses a 1.94# weight. It has a dial caliper that measures in 1/1000th of an inch increments.
Bisch
I tested a bunch tonight. The average deflection of my GT 1535 were 470 the average deflection of my 3555 were 430. Now that's only a difference of 40! And notice I said average. The 1535 varied from 450-530 I measured 3 dozen!
The 3555 were much tighter tolerances. But all very close to 430 I measured 1 dozen all new all full length.
I can't measure FMJS on my scale as they are too thin.
Bottom line for me is. This whole program is really selling me on wood.
QuoteOriginally posted by Orion:
LB: A spine tester will work on made up arrows. The results may be off just a little, but will help you identify any fliers. Traditionally, spine was measured by measuring the deflection when a 2# weight is hung on the shaft suspended between two posts 26 inches apart. The point and nock/fletches, represent a little weight on either end of the arrow, will affect the reading a little, but so little as to be of no practical significance.
For some reason, I believe it was Easton that began testing shafts with a 1.94# weight with the posts spread 28 inches apart. That became the standard used by most manufacturers of aluminum and carbon arrows. It does not give the same results as the previous method.
Of course, each method gives consistent results for that method, but the two are not comparable with each other. For example, a 50# spine using the 2# method yields a deflection of .52 inches. That same 50# gives a deflection of .61 using the 1.94# method, according to a conversion chart prepared by RangersArchery.com. When talking/comparing spine, it's important to know what measurement was used.
The most accurate testers give you the deflection in inches, hundredths of an inch actually. Some display the result in poundage of spine, usually not quite as precise.
Thanks! Im very happy with my goldtips. I seldom shoot groups as I practice with broadheads mostly and shooting groups with broadheads is hard on the arrows. So im mostly shoot 1 or 2 arrows then pull em and repeat.
But i am now curious and if buying a spine tester and taking a couple minutes to batch them up and cut a couple different to get them right can make them fly better im all in!
Time to research testers!
QuoteOriginally posted by Matty:
I tested a bunch tonight. The average deflection of my GT 1535 were 470 the average deflection of my 3555 were 430. Now that's only a difference of 40! And notice I said average. The 1535 varied from 450-530 I measured 3 dozen!
The 3555 were much tighter tolerances. But all very close to 430 I measured 1 dozen all new all full length.
I can't measure FMJS on my scale as they are too thin.
Bottom line for me is. This whole program is really selling me on wood.
Matty, am I reading this right? The 1535's (600 spine rated) basically averaged closer to 500 spine?
And the 3555's (500 spine rated) were closer to 400 spine rated? I'm with you, think I will stick to my wood arrows.
QuoteOriginally posted by Hermon:
QuoteOriginally posted by Matty:
I tested a bunch tonight. The average deflection of my GT 1535 were 470 the average deflection of my 3555 were 430. Now that's only a difference of 40! And notice I said average. The 1535 varied from 450-530 I measured 3 dozen!
The 3555 were much tighter tolerances. But all very close to 430 I measured 1 dozen all new all full length.
I can't measure FMJS on my scale as they are too thin.
Bottom line for me is. This whole program is really selling me on wood.
Matty, am I reading this right? The 1535's (600 spine rated) basically averaged closer to 500 spine?
And the 3555's (500 spine rated) were closer to 400 spine rated? I'm with you, think I will stick to my wood arrows. [/b]
I'm not Matty, but I can tell you from my experiences with GT that you are reading correctly. Every GT shaft I have tested has been way stiffer than marked. I use 55/75's which are marked .400 on the shaft. I have done hundreds of them and NEVER yet had a single shaft spine out at .400. Most are in the .350's - .370's, which is closer to a .340 than a .400. But I get wacked ones in every group also, that might be as high as the high.380's, or as low as the .310's. Those shafts are trash!
For me, it really does not matter what they spine out to because they work, and I tuned to these shafts before I had a spine tester. The spine testing gets the oddballs out of the way so I don't have to deal with them.
Bisch
Yep you read that correct, thanks BISCH...
Now that's not to say I won't use them. I'll still use them but I can weed some out for sure. Get them close like BISCH does. And save the random odd balls for stumping or 3d targets with water or the Grand Canyon behind them. Regardless of how they spine...the thing that really sells me in carbon is its durability. It's an incredible material from this stand point. And for as much as I miss. I need durable! :biglaugh:
keep it going
Guess this explains (partly) why so many folks shoot leave their carbons full length. They think that they are shooting one spine arrow, but in reality are shooting a step stiffer than what the arrow is marked.
Since 2020s are gone, 28&1/4" 2020s is the only shaft my son will shoot and he cannot find any, I read this thread very carefully. He is considering going to carbons and I wanted to give him some advice on which carbon he could cut to that length and shoot out of his favorite Robertson longbow. I must say that I am as confused and skeptical as ever about carbon arrows. Since we use the arrow as a draw length check with tagging the broadhead to the finger, full length is not going to happen. I shoot tapered carbons that I tag at 27", they fly perfect out of one of my bows, not the one I wanted them to, but that is okay as it happens to be the best right hand longbow that I ever shot. He wanted to do the same with carbons for his 60 pound Robertson, but if there are big enough spine variances that he will be able to see, I would never hear the end of it if I told him anything wrong.
Three Rivers Trad .300 are pretty consistent all the way around. I just checked a bunch. Almost no change in spine from shaft to shaft. And batch to batch they seem to always be the same.
I have the wall hang type spine tester. I can spin the shaft and check for a stiff side easily. The needle doesn't move much. While the tester is precise, it's scale doesn't correspond to the big ones. So I don't know how close they are to .300
They say .250 on my tester.
Tedd
Something to keep in mind when spine testing your arrows; any change from a full length bare shaft will affect the results. Manufacturers test their shafts before labeling or printing and without nocks installed. A fletching wrap, feathers, and cutting the shafts and installing inserts will all affect the reading. Also, very few shafts (if any) are perfectly straight. Depending on where the bow of the shaft is located, can also show a variance in spine deflection. The true stiff side may or may not be the stiffest reading side if the bow of the shaft does not line up with the manufactured stiff side. So before you trash a shaft that does not read close to the rest, be sure to shoot it to make sure you are not being misled by other variables.
Okay,
Somebody who is not even a proper redneck "technoweenie" has probably already devised a cheap, rigged device that is perfectly sufficient for at least comparing how close a set of arrows is, regardless of whether it agrees with stated values or not. That's what most of us want to know, whether we've got a "wildcard" in the bunch. I already have such a device for measuring draw weight from a $12 modified digital luggage scale that's scary accurate and an el cheapo Harbor Freight cut-off saw that works great. Okay, whatcha got....let's see it?
QuoteOriginally posted by olddogrib:
Okay,
Somebody who is not even a proper redneck "technoweenie" has probably already devised a cheap, rigged device that is perfectly sufficient for at least comparing how close a set of arrows is, regardless of whether it agrees with stated values or not. That's what most of us want to know, whether we've got a "wildcard" in the bunch. I already have such a device for measuring draw weight from a $12 modified digital luggage scale that's scary accurate and an el cheapo Harbor Freight cut-off saw that works great. Okay, whatcha got....let's see it?
There's a bunch out therein the "inter webs" some of my favorites are sam harpers, with a tuna can and fishing weights. And I think tenbrook did one with a bunch of bananas!
:biglaugh:
Oops double post
Okay chilluns, stumbled across this link that looks entirely doable, even for the mechanically challenged. Wonder if you could chuck the dial indicator in a drill press and lock it at he right height and simple use the arrow mount?
http://www.fieldandstream.com/articles/hunting/2013/10/step-step-boost-accuracy-your-diy-spine-tester