Question...when checking spine with my new favorite toy, the Spine-O-Meter, I noticed something. If I would turn the shaft so the grain is running horizontal the spine was up to 8 lbs. less than if I put the grain running vertical. Say from 68# to 72#. Being as the arrow flexes against the grain (grain is horizontal on the bow shelf so nock is perpendicular to the grain) going around the riser I am assuming you take the spine reading with the grain in the vertical position...? Is this clear...as mud?
Thanks Snag I knew what I was doing till reading this!! LOL!
Grain in vertical orientation is correct.
LOL, so did I until this came up! Thanks for the clarification.
Snag:
You are correct that the edge grain should be verticle when taking a spine reading, however your reason for doing it that way is wrong. The position of the grain is part of the spine standard and is the way shaft manufactures should spine their shafts. That way the consumers will know what the spine of that shaft is when the nock is placed correctly on the shaft and they are purchasing spined shafting. Back in the early days when a bowhunter purchased shafts by the dozen or 100 the archery shop would have spined all the shafts before sale and grouped them by deflection or bow weight. You did not have to worry about the spine being different if you oriented the nock to the spine standard.
It is true that some shafts will spine differently as the grain orientation is changed on the tester, however those instances are usually not common. In my exprience its extremely rare for the spine to increase when the orientation is changed from verticle to horizontal, it usally goes down in spine.
Bob
Darn, I thought this was gonna not give me a headache.............Cupcake, it is time for you to add to this soup!
I concur! Got to let my limited number of brain cells rest now..... :0)
I'll give Kevin (Cupcake) a call and let him know.
I have not much to add here. The wood is stiffer when the force is applied parallel with the grain. Woods are measured with this orientation so that the batch of shafts are the same, as aromakr said. When installing the knocks make sure that they are all oriented the same way to the grain.
This is also an opportunity to adjust the spine a bit; if you would prefer a weaker spine to better match your bow I see no reason why you could not orient the knocks for weaker.
DesertDude tests all his carbons for the same deflection and installs the knocks in the required orientation to get the same spine.
Interesting Kevin. I have never heard this before. So if I have a few that are 72# and the others are 68# I can just rotate the nock a little and get them to come down to 68#. Brilliant! I would imagine I should rotate and check the spine on the Spine-O-Meter to see how far to rotate...? I have a batch of arrows in the making. I will do exactly this! Thanks.
snag:
What Kevin said is true to a point, however not all shafts will vary in spine at various spots on the shafts and some will vary a great deal.
Bob
Thus the nature of wood.
The problem with rotating the shaft is more of a safety concern than anything. Wood arrows should be built so that the rift on top of the arrow points toward the point end of the shaft so that if the shaft breaks, it breaks up and away from the hand. That being said, A arrow that is built for a right hand shooter should not be shot by a left hand shooter as you are turning the shaft over to have the cock feather pointing out and the rift on top of the arrow would now be pointing to the nock end of the arrow and if it broke it would break down and toward the hand.
Rick
Rift, shrift. I make my shafts and there IS no rift. A growth ring runs the full length of the arrow without runout.
I would probably never buy a shaft that didn't follow a growth ring like that.
Guys who make shafts from tree shoots don't have rift to worry about either--no grain orientation either.
Thanks Snag-before you started this thread I had it all figured out-maybe aluminum would be OK after all-this wood stuff is getting so complicated! LOL!
Rift is the feathering of the wood on top and on the bottom of the shaft and runs in opposite directions, It doesn't mean that the edge grain doesn't run the full length of the shaft.
Rick
Bjorn:
Nothing complicated about wood, just some try to make it more complicated than it really is. I wonder how those that came before us ever got an arrow to shoot (before spine testers) You know Ford and Duff just flexed the shaft in the hands and had no trouble with that working. Even bows cut less than center DO NOT HAVE TO HAVE EACH SHAFT SPINING EXACTLY THE SAME. I hate to shout but it seems people don't listen. I've been at this game over fifty years, believe me. And with the modern bows cut too center and past you have alot of spines that will work in the same bow, and hit in exactly the same spot!!!!
Bob
Man i dont even use wood and i got a headache
Eggzactly what I said. There is no "feathering" on my shafts because I follow the growth rings in cutting the squares from which I make the arrows. There is seldom a growth ring that runs out in the length of my arrows. Even less often more than one.
I didn't mean to start this kind of a conversation...just thought it would be fun to get some input on how to proper spine a shaft..vertical or horizonal grain. This had not come to mind until recently. Now that I can spine or check arrow shafts that have been spined it brought up this question. Yes Aromkr I can shoot many different spined shafts through my Blacktail recurve. I was just trying to see if I had arrows that were close in spine and weight how much difference it would make in my hitting the intended target...or if it really didn't make all that much difference. Part of this is that I have been shooting carbons too. Now I am trying to get the woodies to be as accurate as possible. I enjoy it. It is my way of experimenting on a small scale I guess.
Sorry guys I wasn't trying to cause any trouble. The only reason that I even brought it up was that I had a arrow that broke while being shot and nicked the top of my hand. I did a little research and found a couple articles on rift and it made sense. If anyone has a copy of T.J. Conrads " The Traditional Bowhunter's Handbook " he has a short piece on it on page 147. Sorry snag, I wasn't trying to highjack your post. There are people on here that have been doing this a lot longer than me and I do value there opinion.
Thanks,Rick
Sorry guy's, I was just trying to answer some questions, didn't mean to give anyone a headache. I'll just keep quiet from now on!!!
Bob
That's why I value this site...cause there are "people on here that have been doing this a lot longer than me"... Bob being one of them!
I agree snag, Bob has been doing this a long time and knows his stuff.
Rick
A good POC shaft will vary in spine very little regardless of orientation. However, I've never found that weighing against the grain was stiffer than weighing with the grain on average. After all the shaft is natural. You can't compare it to laminations of wood glued together which of course is much stiffer against the lams....Van
I would have to respectfully disagree Van after going through several shafts and trying checking spine with the grain and against it. It varied as much as 10#. This is with one of the best pieces of equipment to check spine with and calibrating it each time. A board will warp with the grain but stand up to a heavier load on the edge against the grain...why? Because it is stronger and flexes less.
In my experience the amount of difference is not always the same, sometimes only a few#; but the stiff side has been against the grain. And I too will attest to the quality of the 'cupcake tester'.
So that's what it's called Bjorn! lol Best spine tester money can buy. I have some of those old ACME POC shafts about made into arrows. I am going to recheck their spine before I fletch. I have been writing in black ink pen the poundage up by the fletching end so I can keep them in similar groups...real sign I have too many arrows? It is kind of nice when trying them in different bows though.
"Cupcake tester", eh. Not exactly my intent for a name when I designed it. I am very flattered that you gentlemen think so much of my design.
One of the biggest attractions for me in this sport is how much science can go into a simple stick and string. I have been setting up my garage and acquiring tools for bow making, so stay tuned, I think the fun is about to start.
Kevin
I can't wait to start bro..........
Kevin, the other day I went out to an orchard they are cutting down to clear for housing. Cut a half dozen 7ft. staves out for bow making! I don't know what I am getting myself into, but I think I will like it!
After putting 4 coats of finish on some POC shafts I have found that some have as much as 4# difference in spine weight if you rotate them from with grain to against grain. Seems like the coats of finish have narrowed the spine range...?
Snag,
Oh boy, more things to ponder. Don't think too hard about all of this because it will probably make you crazy. That is an interesting data point that finish makes them more uniform in spine. Is that consistent with all of them? It would be interesting to see if it happens for many dozens of shafts.
Bow staves now also. Don't get impatient and work them when too green.
This stuff is so much fun that who cares where it leads us. We will be off the streets and our wives will know what we are doing.
Cupcake
It is OK dear, I am off the street and hooking up with cupcake! LOL!
LOLOLOL! Doesn't quite sound, right does it Bjorn?
The next batch of POC shafts I make arrows out of I am going to try and do the spine checking before and after applying a sealing finish more "scientifically". Got me wondering now!
I have dipped one extra time with some shafts to add weight...now I am wondering about spine.
Sometimes this Spine-O-Meter gives me fits!!! Like when you order 2dz 80-85 spine shafts, then you test them and they are from 70-75. Now I have to go through returning them...Frustrating.
hmmmm...interesting Dude, I had thought I would go back through wood arrows I have made to check spine on them. It will be interesting if they fall within the range they were represented as.
snag, after you spine test more than "a few" check back. I've checked 100's of POC and found that against grain or with grain makes very little difference. Some spine more with grain and some spine more against grain. Do you zero the shaft after turning 90 degrees? Just a thought....Van
Good Point Van, not only is it important to zero the tester after turning 90 degrees. But the biggest drawback to that type of tester is getting your eye level with the pointer. When you zero you have to move your head to see if its aligned properly with the mark, then when taking a reading you must again move your head to proper alignment to get accurate measurements.
Bob
Van, yes I zero it and start at the same starting point. I get down even with the pointer and take my time to get every reading accurate...or why even do it!
The Spine-O-Meter is a great tester. This is the second time in 2 days I have herd something negitive about it. Depending on what level your looking at the needle at zero, you MAY be off 1# MAYBE. I hardly think that a 1# reading either way will effect anything since we get our shafts in 5# difference. I know for a fact that when we tested aluminium shafts it was spot on every time. Kevin has designed a tester you can test wood, carbon, and aluminium with the same tester. He uses the 26" span for woods and did the convertion for the other 2 types of shafts. Kevin is at the TOP of his class when it comes to this kind of stuff. Sorry for the Rant, sometimes things just rub a person wrong...
DesertDude:
I think you're spending too much time in the heat. I said nothing negitive about Kevin's spine tester. But his tester is made on the same principle as several other testers that have been on the market over the years. And unless your aware that you must line your eye with the pointer when zeroing and reading you can get as much as 4-5# difference in readings, this is especially true when you get to the high spine shafting as those marks are very close together.
Bob
Are y'all keeping the tester on the floor? Get it up! Mine is on top of a shelf about 4.5 feet off the floor works great, and easy to see level.
Exactly Bjorn.
I concur with everything aromakr said. Plus, it has been my experience that shafts do/can increase in spine from the type/amount of finish used to seal them. The harder the finish dries the more it will effect the spine. That said, we still are only talking 1-3#, which is nothing to get worried over. Furthermore, virtually every bow/archer combination is capable of shooting a 10-20# variance in spine and 50-100 grains in weight with excellent, accurate results.
Snag, one more thing. I've never tested a wood arrow shaft material that had an 8# variance in spine around the circumference. This includes the cheapest dowel you can buy at a hardware store. I would never take the time or invest the expense of making a complete arrow from a shaft that varied more than about 2#'s between with and against the grain.
Either your testing process/spine tester is flawed or you have come across the worst wood shafts for arrow making on the planet :goldtooth: ...Van
Thanks for that input Van. Now I am reassured that it was not worth my efforts. I appreciate your validation.
A truly remarkable collection of ideas on this thread............who knew it would go on for four pages. Nice work Snag!
Snag, Thanks. That's what I'm here for. Good luck. And as Bjorn said - good thread :archer: ...Van