I've noticed that some woods seem to have different dynamic spine when it comes to rated spine and tuning than others. For example, years ago I shot spruce shafts (65-70#). I switched to doug fir and I need 80-85# to get good flight. Has anyone else noticed these kinds of differences between wood species? I ask because doug fir is the only wood I know where 80-85# shafts are easily obtained...
Have you considered poplar? Or even hickory?
I've considered poplar, couldn't find spines around 80#. I've used hickory, but it's so heavy and hard to keep straight that I didn't like it. I'd like to go with a lighter arrow, maybe a 400 grain bareshaft and I don't know if the difference I've noticed in spine is real or maybe my form has changed...
Yeah hickory is heavy. PM John fletch, he makes warbow arrows with poplar and might have some shafts that'd work for you possibly. I know he's got 80-90 spine in 3/8", but maybe he has some smaller dia./ lighter ones?? No luck with POC?
POC is an option...maybe I need to clarify my problem.
Currently I shoot 80-85# doug fir. My bow is 56#@28, but I'm drawing to almost 30". I've noticed in the past that some woods appear to require a much stiffer spine than others, but I never did any extensive testing. So, the question is if that difference in rated spine and effective spine real? i.e. will a 80-85# doug fir shaft behave the same as a 65-70# spruce shaft? If so, I can get a test pack problem solved, if not I don't want to bother with a test pack if I'm going to have trouble finding shafts of correct spine anyway.
Ok I gotcha now. Experiencing a 10-20# variation in rated/static spine and dynamic I could see how that could be frustrating. I'm just getting into woodies myself and I've been doing lots of research before I spend too much money.. The word is the bending of an arrow in a spine tester can definitely vary depending on the orientation of the arrow...differences in grain etc will affect the reading as the arrow is rotated...and yeah different woods can have different bending depending on grain density and orientation. That's why it's so important to get high quality shafts that someone really took the time to select carefully...shafts from lower quality wood that maybe only got measured hastily could cause problems. Good luck and the REAL experts will probably expound on these couple factoids I mentioned.
I get consistent results from spine testing shafts of different woods, but I am careful to orient the growth rings the same way.
I go against the grain, as it were, and put the rings in line with the string. (With plastic nocks, there is no chance that the string will split the shaft, as was the reason self nocks were always placed at 90 degrees from the string.)
Maybe I would not get such consistent results if I were shooting bows as heavy as yours. My heaviest is 50#
Your static spine readings are likely correct. Doug fir is physically heavier than Sitka spruce and it doesn't recover as quickly. That's why you need more static spine in Doug fir. If you were shooting hickory or some other hardwood, you would need more static spine yet.
If you can find POC in the same spine and physical weight as the spruce, it should fly the same. The lightest Doug fir shafts at a given spine weigh pretty close to the heaviest Sitka spruce shafts at the same spine. Thus, if your Doug fir supplier can supply you with very light (for the species) Doug fir shafts, you should be able to use them in a spine pretty close to what you're using in Sitka spruce. Hope all this makes some sense.
The short of it is that as you increase physical weight and reduce elasticity, you need to go up in static spine, and vice-versa. Good luck.
I've shot both Sitka and Doug Fir quite a bit and haven't noticed any difference in dynamic spine between the two; if my bow shoots a 60 lb fir, I can shoot a 60 lb Sitka, same length and point weight, from the same bow. Of all the arrow woods, fir is my favorite. I find the fir to be a "snappier" wood and it seems to me to recover quicker than any other wood.
I don't know what bow you are shooting, but 56@28 drawn to 30" is 60-62 lb and with a 31" BOP arrow, 80-85 spine seems right in line. Has your bow or form has changed from your Sitka Spruce days?
fletcher,
my form has changed a bit. I'm drawing about 2" longer now. In my spruce days I was shooting a 70# bow (mild R/D, D-shaped longbow) and 65-70# spruce with 160 up front. I never bareshafted those, but they flew great even with 4" fletches.
I love fir arrows, but I'd like to have the option of shooting spruce (or even POC) because it's lighter, but it's not easy finding 80-85# shafts in those woods...
Cool. I knew we'd get some good info soon on this thread. I chimed in to keep it at the top, learned a couple things. Love Tradgang.
Rick: Your experience is what I was getting at in my second paragraph. At the same physical weight, Doug fir and Sitka spruce of the same spine should shoot the same. But unless one specifies the physical weight when ordering shafts, the Doug firs are likely to be physically heavier than Sitka spruce. I'm assumed that was Gringol's initial situation.
I haven't shot enough Doug fir side by side with spruce to say it's springier. I have shot a lot of it along side of POC, and I think cedar has the edge there. Regardless, the differences are small. I think physical weight plays a bigger role than the wood's elasticity in having to bump up static spine a little.
Hildebrand has been the main supplier of Sitka for quite a while and they have stopped doweling 23/64, likely due to lack of demand; 23/64 can be a hard sell these days. Sitka just doesn't have the spine of D Fir. Fir does vary in weight quite a bit and you should be able to find some in the low 400's if you went direct to Surewood.
Thanks for the help, guys. After your answers and a conversation with Hildebrand, it seems it is possible to find both lighter doug firs @80-85# and 80-85# spruce. You just have to make some phone calls, and then snatch them up when they are available. Since I haven't tried either yet, I don't know which way is more reliable...
Personally I prefer 23/64. I guess I'm a bit weird. It just seems easier to put a self-nock and then a back taper on a fat shaft...
QuoteOriginally posted by gringol:
I've noticed that some woods seem to have different dynamic spine when it comes to rated spine and tuning than others. For example, years ago I shot spruce shafts (65-70#). I switched to doug fir and I need 80-85# to get good flight. Has anyone else noticed these kinds of differences between wood species? I ask because doug fir is the only wood I know where 80-85# shafts are easily obtained...
NO, no difference in spine needed between woods-POC, Sitka Spruce, Douglas Fir, Lodgepole Pine, Western Hemlock, Ash, etc. at least in my 40+ years of making/selling arrows I've not noticed a difference.
My guess is something else changed from"years ago" to the present.
kelly,
while I was still shooting spruce I made a switch to ash and I noticed a huge difference. I could not get decent flight with ash of the same spine rating as the spruce unless I used 6" native-cut feathers on the ash. At the time I was shooting spruce with 4" shields...
So, remembering that experience I thought there might be a similar difference between fir a spruce...
Kelly: I would agree with you as long as the shafts are the same physical weight and the same diameter. However, often they are not. On average, Doug fir runs 50-75 grains heavier than POC. Now, the lightest Doug fir might come out about the same as the heavier/heaviest POC, but unless one stipulates the physical weight when one ordersshafts, one is likely to get the middle weight or whatever the vendor happens to have a lot of.
A more extreme example might illustrate this. A 700 grain hickory shaft spined at 50# does not shoot the same as a 500 grain POC shaft spined at 50#. It takes more of the bow's energy to get the 700 grain arrow moving, and that additional arrow weight causes the arrow to flex more, i.e., show a weaker dynamic spine. If we want that 700 grtain arrow to shoot/act like the 500 grain arrow, we need to increase its static spine.
In short, changing the weight of the arrow changes the dynamic spine required and thus the static spine required to achieve it. That's what folks are doing with carbon arrows all the time in adding or taking weight off the point.
Arrow diameter also affects static spine. Gringol, your arrows initially may have been 11/32, and those you're shooting now may be 23/64. 11/32 shafts of the same spine will act stiffer on the bow compared to 23/64 shafts because they ride closer to the center of the bow. Thus, a lighter spine 11/32 spine will shoot the same as a heavier spine 23/64. Add in the physical weight differences between the two diameter shafts, and it becomes pretty clear that more spine could be needed.
It's possible, too, of course, that the arrow shelf on the bow you're shooting today is not cut to the same depth as the bow you were shooting some years ago. If the bow you're shooting now is cut further from center, it would require more spine.
All these things are cumulative. A heavier arrow, thicker arrow and sight window cut proud of center all require an increase in static spine. If you're shooting a fast flite string now, drawing longer, etc., they, too, would require more spine. Together,these factors could easily account for the difference you're seeing with your present set up vis a vis what you shot years ago.
So, I'm thinking of building some Doug Fir arrows. Is it a waste of money to get a POC test kit to find the right spine shaft?
Why not get a D.Fir test kit?
All things being equal with your bow setup and your draw length one should not see any differences between different woods of the same spine regardless of weight.
All types of wood used for shaft material will have a given 100-150 grain weight variance from highest to lowest in the same 5# spine group/same diameter. Some like Douglas Fir may have 200 grains or more variance and others like Sitka Spruce are closer to the 100/120 grain variance in a given spine group of the same diameter.
If weight was a more critical factor than spine then the 480 grain 60-64# spine POC would be weaker than the 360 grain 60-64# spine POC-is that what I'm hearing from your point of view, Orion?
I have been known to have arrows of various grain weights in my quiver, various woods and sometimes 10-20# spine difference and they all fly the same-perfect. Sure the heavier arrow will drop more but we are talking arrow flight here and it will still fly straight if spined the same as the lighter one.
Gringol, check with Ted Fry at Raptor archery, I got some 80-85# spruce from him a while back, they were 24/64th.
Eric
Nope: I'm not saying that weight is a more critical factor than spine, Kelly. I'm saying that physical weight affects the dynamic spine of an arrow. And yes, a 480 grain arrow spined the same as a 360 grain arrow of the same material would show dynamically weaker. Now, you put feathers on those shafts and shoot them and you probably won't notice a difference. Would likely show up in bare shafting though.
Feathers ameliorate some big discrepencies in arrows. I, too, often carry a quiver full of arrows that may vary by as much as 100 grains in weight and 20# in spine, and they all shoot well and pretty close to the same spot.
I've found that most bows are pretty tolerant of spine variations. I over spine by 10-20# on most of my bows intentionally. I don't doubt that there's an optimal arrow spine and weight for each bow, and a lot of folks spend a lot of time trying to find out what it is. I don't. I know the physical and spine weight woodies that shoot well out of my bows, and as long as I'm in the ball park, and my fletched arrows are flying straight and where I want them to hit, I don't worry about other stuff.
But over the years, I have learned that physical weight of the shaft, it's diameter, bow string material, the amount of bow centershot, draw length, etc. all affect the dynamic spine of an arrow, i.e., how it behaves coming off the bow., and that, in turn, affects static spine requirements.
This is not rocket science nor is it complicated. Just put some feathers on shafts that are relatively close to your specs and they will fly just fine.
All bow/archer combos are capable of shooting 15-25# variance in spine with 100-200 grain differences in weight, in any type of shaft material with very good results.
There is no one perfect combination that is the ONLY combination that works in YOUR bow.
Again don't make this more complicated than need be, feathers are on there for a very good reason-steering-so why try to re-invent the wheel by shooting arrows without them!
I agree, Kelly. I joined this discussion to provide some plausible explanations as to what may have caused the changed spine that Gringol experienced in his shooting. Lots of possibilities. If I hijacked this thread with my pontifications, I apologize.
Hi all - any advice on bamboo spining? I'm still trying to get the right weighting - most of the shafts I've made so far I've matched to spruce weighting (10-15# over draw weight) but I'm still seeing too many over spined arrows - increasing point weight solves the problem so it looks like the next step is to go lower. Thx - M
Thanks for the thoughts, guys. I think what I noticed in the past was caused by the difference between static spine and dynamic spine. Orion's point regarding the overall mass of the arrow changing the dynamic spine seems like a logical explanation. I'm sure there are other factors involved, but my initial observation between ash and spruce shafts was made on the same day, with the same bow. Only difference was the shaft...
Kelly, I agree that feathers can fix a lot, and I want you to know that I'm not one of these guys that spends days, weeks, or even months tuning. I typically get a test kit, shoot one arrow of each rated spine and pick the best one. The whole process take about 5 minutes...I first started bareshafting because I could not get ash arrows to fly the same as the spruce I was shooting of THE SAME SPINE RATING. I stripped the feathers off the ash and they flew down range at more than 45 degrees to the target and promptly snapped on impact. The spruce did not fly perfectly when bareshafted, but they were certainly pointed in the right direction and didn't break on impact. From my experience there is definitely a difference between at least some woods.
Could sluggish woods (like ash) be less forgiving when the rating spine is too light? Makes sense to me...
I posted because I'd like to save myself a few $$$. I don't want to buy materials build a new set of arrows and then have trouble getting BHs to fly...
Mark, I'm certainly no bamboo expert, but I've heard many times that the spine of bamboo shafts is much, much more forgiving than wood. So much so that people don't even bother testing the spine of bamboo shafts...Try starting a thread, you'll probably get some more "expert" input.
QuoteOriginally posted by gringol:
Thanks for the thoughts, guys. I think what I noticed in the past was caused by the difference between static spine and dynamic spine. Orion's point regarding the overall mass of the arrow changing the dynamic spine seems like a logical explanation. I'm sure there are other factors involved, but my initial observation between ash and spruce shafts was made on the same day, with the same bow. Only difference was the shaft...
Kelly, I agree that feathers can fix a lot, and I want you to know that I'm not one of these guys that spends days, weeks, or even months tuning. I typically get a test kit, shoot one arrow of each rated spine and pick the best one. The whole process take about 5 minutes...I first started bareshafting because I could not get ash arrows to fly the same as the spruce I was shooting of THE SAME SPINE RATING. I stripped the feathers off the ash and they flew down range at more than 45 degrees to the target and promptly snapped on impact. The spruce did not fly perfectly when bareshafted, but they were certainly pointed in the right direction and didn't break on impact. From my experience there is definitely a difference between at least some woods.
Could sluggish woods (like ash) be less forgiving when the rating spine is too light? Makes sense to me...
I posted because I'd like to save myself a few $$$. I don't want to buy materials build a new set of arrows and then have trouble getting BHs to fly...
Mark, I'm certainly no bamboo expert, but I've heard many times that the spine of bamboo shafts is much, much more forgiving than wood. So much so that people don't even bother testing the spine of bamboo shafts...Try starting a thread, you'll probably get some more "expert" input.
Feathers are not meant to fix anything-they are to steer the broadhead tipped arrow. Without sufficient steering by the fletchings the blades of the broadhead will do the steering.
Now when talking about bareshaft testing one does not use broadheads so there is no steering mechanism. In order to get a somewhat straight flying bare shaft one needs to increase the spine to nullify paradox as much as possible to steer the arrow hence why so many results of bareshaft testing need such stiffer spined arrows-20# or more than really needed. If bareshaft testing is so great and such a perfect way to find ones "perfect" spine then why does one then put feathers on these perfect bareshafts? I suggest it is to steer the broadhead-so why not start here instead.
Agree that the difficulty in tuning/spine is with broadheads and that is why myself and many others, including everyone from the old days find their arrow spine by shooting broadheads first. If broadheads fly perfect then any other point one uses thereafter will fly perfect. Why take all the time trying to find spine with field points and then still not know if it is correct with broadheads-rather tune with broadheads first.
That said there still is not one perfect spine per bow/archer combination. Rather several-10-20# variance and still have perfect flying broadheads. It just is not that critical because we as archers are not machines since all bows are capable of far better accuracy in the machines hands than the archers. If it was that critical the archer would have good and bad flying arrows(even though they are identical in every way) depending upon uniformity and repeatibility of the archers form, or not. There is built in flexibility in the equipment we use to accomidate our flexibility of form. Sure we all strive to repeat/perfect the from process as close as possible in each and every shot but we are not machines.
Regarding grain weight it has been my experience that heavier grain weight broadhead tipped arrows are easier to control than really lightweight ones given all else is identical, spine, diameter, fletching, etc. plus no changes on the archer end including the same bow, draw, etc. Same reason why heavier arrows reduce string noise and bow vibration/recoil/shock.
Regarding your original question-re douglas fir compared to Sitka Spruce. Each wood has a grain weight variance within the same spine group of 100 grains and more-even more with Douglas Fir. That said, the light end of douglas fir is very close to the mid range end of Sitka Spruce so the difference does not need to be that great. If you know the grain weight of your spruce then tell Neil or Roxanne at Hildebrand what that grain weight is and they will get as close as possible.
I'm guessing that your spruce may be on the light side, spinewise since you said they didn't bareshaft very well either so an increase in spine will probably be good for you anyway. Tell Neil and Roxanne about your equipment and what you want to accomplish in your finished broadhead tipped arrow and they'll help you get the right spine-they've had a good teacher. If in doubt, always err on the high side. And if the required spine is not available but the next 5# spine group below is just use longer feathers or 4 fletch over 3-either ow which will have the effect of the next higher spine group, or maybe one can use a shorter arrow-sometimes even 1/2" could be enough if on the edge of spine.
Sorry for being so long winded here-this is my last post on this subject. Enjoy the flight of the arrow!