Most of the questions I receive are about arrow spine. With aluminum arrows there is a wide range of spine weights and selecting an arrow is much easier than with a carbon shaft. In this short article I will describe what will work with all arrows. Tuning your bow to carbon arrows becomes even more critical. I have tested many different carbon shafts over the last few years and can tell you not all carbons are created equal. In my testing I have found some brands of arrows will vary as much as 30 lbs. in spine weight and over 30 grains in weight. Another thing I have found is a lot of carbon shafts have a strong and a weak side making them even harder to tune with. I have also found that the more expensive shafts are far more consistent both in spine and weight. I think I've tried about every way of weighting them possible with mixed results. While I don't want to rub anyone the wrong way, I will go into this article using Easton Axis or Beaman Max 4 as an example, because I have found them to be very consistent in all respects.
First you will need to set the brace height of your bow. With the Bear's Paw One Piece longbow, set it to 6 3/4" from the throat of the grip to the string. With the Bear's Paw Take Down longbow set it to about 6 7/8". For the Lightspeed set it to 7 1/4" and for the Classic set it to 7 5/8". You can vary the brace height up to a 1/4" either way to suite you shooting style. If the brace height is low, twist the string to raise it. All strings will stretch so you need to check your brace height periodically. Now you will need to set your nock set. For bows shot off the shelf a good starting point is 1/2" above square, for bows shot off an elevated rest a good starting point is 3/8" above square. Once this is done you need to shoot the bow with a bare shaft about 2" longer than your draw length. I start from about 5 yards from the target. If you are right handed and the arrow enters the target with the nock end to the left of center (Ref. 1) the spine is too weak. You will need to adjust your arrow length in order to stiffen it's spine. If the arrow nock is right of center (Ref. 2) the spine is too stiff. If your spine is too stiff you will have to add weight to the tip of the arrow in order to weaken the spine. With carbon arrows you can epoxy the insert in and trim the nock end of the shaft. If your spine is too weak, the nock will be to the left of center (Ref. 1). I trim a 1/2" off and shoot again. If it is still too weak, trim off another 1/2" and shoot again. Each time you trim and shoot the arrow you should see a correction. When you are getting close to your arrow entering the target centered, trim only a 1/4" at a time.
As you're doing the spine test I'm sure you've noticed that the nock is either too high or too low. I use a tied on nock set so I can adjust it up or down to get the arrow flying level. If your nock is too high (Ref. 3), you will need to lower the nock set. If your nock is too low (Ref. 4), you will need to raise the nock set. Once you get the arrow shooting straight at 5 yards, back up to 15 yards and check your arrow at that range. With just a few minutes of tuning you can get your new Bear's Paw Bow to shoot a bare shaft at 30 yards.
Once you have your bow tuned, make sure to measure your brace height and nock set so that next time you put on a new string you won't have to through the whole process again. Remember to tune your bow with the same weight of field tips as your broadheads. I hope this will help you in tuning your new bow. A well tuned bow (Ref. 5) will shoot better, have cleaner arrow flight, shoot better groups and have better penetration for hunting.
With this general knowledge you can tune wood or aluminum shafts equally well. Just remember "left is weak spine, right is stiff spine" and you too can tune your bow to shoot that perfect arrow. If you are left handed, the left and right spine will be reversed.