WOODEN ARROWS AND SPINE, THE EFFECTS OF CUTTING THE ARROW TO YOUR LENGTH

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duffy

New member
Hi

I make my own arrows but have no way of testing accurate spine, i buy arrow shafts from a shop that they write on the spine of the arrow, say 35-40 spine.

the shafts are 32" in length, however i cut the shaft down to 28" does that effect the spine? does it change it? or just the weight is changed (i cut from one end only)

by the time i put on my point and nock the total arrow measurement from tip of point to throat of nock is 29" long.

so is my made up arrow still 35-40 spine, its only that bow manufacturers mention about using arrows so many spines over the bow weight and if im chopping the shaft down do i get different numbers at the end, ive always tended to go on total arrow weight at the end to make sure its safe for my bow.

any help would be appreciated
 


Si2

New member
Static spine rating in lbs is measured across a 26" arrow length.
A long arrow is rested on two points 26" apart. The bits that hang off the end don't really matter.

So it doesn't affect the rating written on your arrow....

BUT it does affect dynamic spine and that value is the resultant of a complex equation with several varaibles. These include static spine, arrow length, pile mass, arrow geometry (tapered, bobtailed) fletching size, fletching shape and arrow mass, to name a few.

The static spine is a great way to group bare shafts - the rest needs plenty of experimentation, which is the fun bit..


Si
 


Skippy

New member
Static spine rating in lbs is measured across a 26" arrow length.
A long arrow is rested on two points 26" apart. The bits that hang off the end don't really matter.

So it doesn't affect the rating written on your arrow....

BUT it does affect dynamic spine and that value is the resultant of a complex equation with several varaibles. These include static spine, arrow length, pile mass, arrow geometry (tapered, bobtailed) fletching size, fletching shape and arrow mass, to name a few.

The static spine is a great way to group bare shafts - the rest needs plenty of experimentation, which is the fun bit..


Si
And if you do get a spine tester like I did. Check the things is calibrated!!! Oops!

Has anyone ever tried bare shafting longbow arrows? I did try it the recurve way, but ended up having to just put a flag out as a reference point to aim at. I couldn't get my shafts anywhere close to the target, so just had to settle for them grouping where they were. Maybe this year I'll get around to trying to match shafts to bows, but with 4 different bows this could take me all year! :gloomy:

It seems to me that as long as you manage to produce a set of arrows that groups (hopefully somewhere near the target!) then you are quite literally going in the right direction.

The time and effort and pain involved in trying to get a close matched set that suits your bow and shooting style is enormous. I've only gone as far a weight matching so far. Some people seem to think that accurate spining is more important than weight matching.

Personally I think that until you are shooting at a level where most of your arrows are hitting at 100 yards then any inconsistency in your shooting outweighs the arrow variation. However every little helps! :eek:
 


Personally I think that until you are shooting at a level where most of your arrows are hitting at 100 yards then any inconsistency in your shooting outweighs the arrow variation. However every little helps! :eek:

I'd disagree slightly with this purely on the basis that if your arrows aren't matched then you will never know if you are being consistant in your stance/draw/anchor etc as it could just be the arrows flying differently to each other rather than a problem with your technique.

But going to the original post I would reccomend Richard Head longbows, with their online store you can buy 5/16 Boyton pine shafts that are spine and weight matched, it costs a little more but I think it is worth it if you don't have time to get to a shop yourself, with their matching service they will match your specified spine weight by +/- 1lb, so if you ask for 43lb spines then you would probably get a mix of 42, 43 and 44ib weights, they also match the physical weight of the shafts to within 25 grains which isn't too bad.

You also mentioned that the bow manufacturer said get spine weighted shafts over the bow weight, thats a new one to me so I don't really know, but as was previously mentioned the static spine won't change as so you do not cut your shafts to less than 26 inches.

Hope thats some help!
 


Skippy

New member
I'd disagree slightly with this purely on the basis that if your arrows aren't matched then you will never know if you are being consistant in your stance/draw/anchor etc as it could just be the arrows flying differently to each other rather than a problem with your technique.

But going to the original post I would reccomend Richard Head longbows, with their online store you can buy 5/16 Boyton pine shafts that are spine and weight matched, it costs a little more but I think it is worth it if you don't have time to get to a shop yourself, with their matching service they will match your specified spine weight by +/- 1lb, so if you ask for 43lb spines then you would probably get a mix of 42, 43 and 44ib weights, they also match the physical weight of the shafts to within 25 grains which isn't too bad.

You also mentioned that the bow manufacturer said get spine weighted shafts over the bow weight, thats a new one to me so I don't really know, but as was previously mentioned the static spine won't change as so you do not cut your shafts to less than 26 inches.

Hope thats some help!
I think that I might have been as clear as mud as per usual! :covereyes

All I meant was that the standard 5lb range of spine is probably okay for most people. Finding which 5lb range is sometimes more of a problem. My first set of decent arrows I made that shot consistently well was only matched to a 5lb range, but they were weight matched to within 10 grains. I think that this is especially important if you are having to go with light arrows to get a reasonable sight mark at longer distances.

If you can get spine matched and/or weight matched arrows at a reasonable price and your are confident that the spine is definitely right for you then definitely get them.

In my case it has taken a year of playing around to find out what weight arrows suit which bow. I haven't fully nailed down the drawweight/spine yet. It is one of those things where you see lots of different opinions on the shooting line. I've heard of ranges of +10lbs to -20 lbs drawweight depending on the archer. Personally I go for about 10 - 12 lbs under my actual drawweight. That's before you start to muck around with tapered, barrelled or footed shafts if you choose to go down that route.
 


Ah, I see :) and yes, getting to that right weight bracket is the tricky part, once you've done that you're most of the way there. Its just a bone of contention for me that most online shops offer the 5lb weight brackets, but they also have their +/- 1lb leeway, so you could end up with a dozen shafts ranging from (assuming 40 - 45lb bracket) 39lbs to 46lbs. That to me isn't very good, which is why when I spotted the spine and weight matched option in Richard Head longbows I was very happy :poulies:

And it took me about a year to get the recipe for my arrows just right as well! And for me 12lbs less then my draw weight does lovely
 


duffy

New member
thanks for all your replies, lots of interesting information, i will check out richard head longbows.
 


Eddie Edmunds

New member
they also match the physical weight of the shafts to within 25 grains which isn't too bad.
In my opinion 25 grains is quite a big difference. I make my own, and although it does take time it's worth the effort. Last season?s Sitka spruce arrows which I have just shortened by 3/4' to 28' (due to 3 breaking at the pile) are all within 2 grains @ 362-363 & spine 40-42. Nocked up a spine tester as mentioned in the DIY forum by Si2 - thanks Si. I checked the balance point recently as some say this can be just as important, and they were all pretty much identical at just under 60%. They shoot just as well out of both of my bows, 42 & 52lb. Got my MB with them last year so that must say something. About to start work on a new set that have been rear tapered so looking forward to trying them when done.

Looking forward to shooting with you again next year Skippy.
 


blakey

New member
Hi

I make my own arrows but have no way of testing accurate spine, i buy arrow shafts from a shop that they write on the spine of the arrow, say 35-40 spine.

the shafts are 32" in length, however i cut the shaft down to 28" does that effect the spine? does it change it? or just the weight is changed (i cut from one end only)

by the time i put on my point and nock the total arrow measurement from tip of point to throat of nock is 29" long.

so is my made up arrow still 35-40 spine, its only that bow manufacturers mention about using arrows so many spines over the bow weight and if im chopping the shaft down do i get different numbers at the end, ive always tended to go on total arrow weight at the end to make sure its safe for my bow.

any help would be appreciated
I play around with arrows a lot, because of the shooting system I use. First thing I'll suggest from the outset is that you need to know what spine chart your supplier is using. There's a great deal of difference between a Modern Longbow chart, and an ELB chart. Generally speaking I believe it's accepted the ElBs will shoot a spine about 10 lbs softer. The longer your arrow is, the weaker it will shoot (bend more). Also the heavier your point weight is, the weaker it will shoot. You can draw up a graph for this. I think from memory that 25gns will acct for about 5 lbs in spine, and an inch in length will account for about 2 lbs. i believe that for good long distance shooting, you will need a matched set of arrows, matched to within 1 lbs of spine, and a maximum of 5 gns in weight. Weight is critical at distance, because heavier arrows will simply drop faster. Achieving this sort of match in wooden arrows is of course incredibly difficult, and is why bought tournament arrows are so expensive. The best set of arrows I have ever seen were all cut from the same straight-grained billet of timber. Cheers
 


In my opinion 25 grains is quite a big difference. I make my own, and although it does take time it's worth the effort. Last season’s Sitka spruce arrows which I have just shortened by 3/4' to 28' (due to 3 breaking at the pile) are all within 2 grains @ 362-363 & spine 40-42. Nocked up a spine tester as mentioned in the DIY forum by Si2 - thanks Si. I checked the balance point recently as some say this can be just as important, and they were all pretty much identical at just under 60%. They shoot just as well out of both of my bows, 42 & 52lb. Got my MB with them last year so that must say something. About to start work on a new set that have been rear tapered so looking forward to trying them when done.

Looking forward to shooting with you again next year Skippy.
Yes 25 grains from one arrow to the next is quite bad, I also make my own and on a set of six I allow a three grain weight varience which seems to be fine, I was merely pointing out that the service Richard Head longbows provide seems to be superior to all the other online shops I have come accross, most of whom only offer a seven pound spine and 30 grain weight bracket.
 


sunmouse

New member
I've found that the more effort and energy you put into matching your arrows, the more satisfaction there is in shooting them, knowing that they will fly right. My method for matching arrows is to take the 5/16s in the 30-35 bracket at Wales Archery and 'roll' them along the desktop disgarding the ones which make the most noise or don't seem to roll straight and checking the grain. Then, where possible, weighing them on a grain scales to find out how heavy each shaft is. This is all before selecting the components and then cutting them down to size. I usually have mine about half an inch longer than my draw length.
 


Raven's_Eye

Active member
Ironman
I've found that the more effort and energy you put into matching your arrows, the more satisfaction there is in shooting them, knowing that they will fly right.
Plus you grumble, groan and get more annoyed when someone else shoots it with another arrow. Its one thing for you to break it, but when someone else does it isn't half annoying.
 


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