How do I know if my arrows have correct spine

[Odie]

Ok folks, here goes:

I am shooting a 40# traditional longbow. I am not using arrow shelves, just shotting off the hand.

I read something arrow spine and how it should match your bow.

The point is that I have ben using wooden arrows and would like to continue using them (somehow using aluminum does not appeal to me...).

The question is: ho do I tell if my arrows have the correct spine. They have not been made specifically to the bow, in Poland vendors do not care about such things, and when I was buying the stuff I did not know any better...

I would like to check it at home. I do not have any special equipment... Is that possible?

Cheers

[robtattoo]

The best way (I'm told) is to shoot 3 of your arrows as normal, to get a good central grouping. Then shoot 3 unfletched arrows of the same type/size, using exactly the same aiming point. If the bare shafts fly to the right, the spine is too light. If they fly left, the spine is too heavy. You may well have to de-fletch some of your arrows to do this & then re-fletch them afterwards. Alternatively, beg, borrow or steal a spine-gauge

[joetapley]

The question isn't do I have the right spine. It's really are my arrows the correct ones for my bow. There have been a number of criteria suggested for assessing this for recurves. The conventional one is the distance between fletched arrow and bareshaft arrow hits at 30 metres. Distance greater then X then arrows no good - untuneable.

No idea re a longbow. I've heard (Russel French I think) that stiff arrrows should be deliberately selected for longbows.

[Macbow]

I am assuming you are right handed - if you are shooting off the hand get your brace height and your bow hand and nocking position correct first as you need to be as consistent as possible. Without a shelf your arrows will need to bend around the handle on release - too stiff they don't bend enough so will group left, too soft they will group right. Usually I find bows that are shot off the hand prefer arrows that are spined below the bow weight but then again it depends on your draw length, length of shaft and weight of the point. A heavier point has the effect of lowering spine so try playing with different point weights. Also adjustments to brace height can affect where your arrows are grouping - a lower BH will make your shafts behave stiffer. If you really do not know what spine shafts you are getting and have no access to a spine tester you can try tuning the arrows to the bow. Quite often even in a 45-50 lb batch of arrows there is always one that is too stiff, sometimes 10+ lbs over. Rather than not use it I chuck the shaft into an electric drill, and spin the shaft through some 120 grit sandpaper held in my left hand. Wear a glove as it gets hot and wear a mask as cedar dust is not nice. Finish off with a finer grade. Using this method I can get all of my shafts down to virtually the same spine. The stiffer arrows you can leave longer, if they are too soft then cut them shorter and use lighter points
Tuning can get very complex as so many variables are involved - just be methodical. Make small changes, one at a time, before trying something else. Good luck.

[Odie]

I have had a look in the Net and I found some articles about home made spine testers (here: http://www.geocities.com/archeryrob/spine_tester.htm.

I think I'll be building one soon (this or next eekend maybe).
In the worst case it will give me SOME idea about the spine, as now I am virtually clueless.

My question is: the simple testers use 26 '' distance between propping points. I know that my arrows are longer (i think 30 '', but can not measure them right now, as I am typing from work). Can I test them on 26'' tester (and use tables to find out the spine) or do I have to change the distance between props to 30'' (or other corresponding to arrow length)?

[Macbow]

I think most spine testers are based on 26" between the posts - mine is. As for your bow shelf, your modifications look OK. You do not need to go too deep - just enough for the arrow to sit on. Alternatively shape a small peice of wood and glue it on. Then cover the shelf in a small peice of leather or velcro.

[Odie]

Thx MacBow,

I have nother question though:

If I cut the shelf in, the cut should be 90 degrees angle, as well as the new arrow rest should be exactly perpendicular to the bow stave plane. Am I right?

Or should I keep another angle?

[Macbow]

Odie, take a look at my site (click my signature) and on the links page check out Border, Blackbrook, 3 Rivers and Bowtec. You will see lots of photos of AFB bows. Take a close look at the shelves on these bows and try something similar. I would be careful removing too much wood from your riser at the strikeplate area as you could weaken the handle too much. Just enough for your arrows to sit on is fine - about 7mm is sufficient and go for a 90 degree angle. I do know a guy who shoots off a cheap plastic Hoyt rest on his AFB. It's not strictly trad and not comp legal but he's happy and that could be another option that doesn't involve chopping into your bow.