Bare Shaft help with POC 70#spine

[snag]

I made up some POC 70# spine weight arrows. Tried bare shafting with RH'd 55#@28" center cut recurve w/ FF string. I cut shaft to 29.5" and tried 160gr. tips, showed weak, tried 145gr. still weak, went to 125gr. still weak. The arrow flies right at the bullseye and in the last yard it veers to the right and hits about 8" right of the bullseye.  The fletched ones show stiff and high....? Should I exchange the 125gr. with 145gr. and see if the fletched ones come in? Do you think these 70# shafts are just too low spine for my bow?  I do have a 45# recurve that I tried them in and they shot stiff w/ 125gr tips. Could go up in tip weight with this bow I guess. Kind of hoped I could get them to fly good out of the 55#er though.....?

[Dr. Ed Ashby]

What distance are you shooting at?

Sounds like they might be over-spined enough that they're slapping the bow, causing them to show a false weak spine. Try a lot heavier tip weight and see what happens with the bare shafts.

Ed
TGMM family of the Bow

[Gator1]

I was a victim of "False Weak" bareshafting, and it is costly...

[Orion]

70# should be great plenty for a 55# bow.  Do you have a spine tester to test the spine.  Often, the spine is off quite a bit on purchased shafts.  If you've been shooting carbons, don't forget to raise your nock point to compensate for the larger diameter woodies.  Are you doing all your testing with one arrow?  You could just have a bad arrow/shaft.

[snag]

Hi Ed! I am at 20yds. I have bare shafted up to 80-85# POC with this bow. They have had 160gr. tips. I will try heavier tips...that would be great if I could go heavier.

[snag]

I started out by checking spine...had to use my new Spine-O-Meter!  Those old ACME shafts were all either 68# or 70#. You know nock height is part of the problem! I have been shooting CE arrows. Thanks for the reminder. I will fix the nock height and then try some 160gr and 190gr tips.

[Dr. Ed Ashby]

David, before you start trying to tune fletched shafts to bare shafts, just work with the bare shafts until you have the dynamic spine right. Start at a bit closer range - about 12 to 15 yards.

Don't worry about the direction of nock kick on impact. Pay attention only to the point of impact; whether it is left or right. If you get a LOT of nock up or nock down, you might want to do a bit of nocking point adjustment on the string, but otherwise forget about any nock kick.

Don't worry about up and down orientation of the impact. I find I can do this tuning best by shooting at a vertical line - a strip of tape on a cardboard backing.

If you normally shoot with your bow canted, don't do that for this initial dynamic spine tuning. Shoot with your bow vertical; otherwise the spine deflection is at an angle, not directly right-left.

Ed
TGMM Family of the Bow

[snag]

You know I forgot about that too Ed! No canting the bow. Sometimes I wonder how I get dressed in the morning! I have been shooting so well with a little bit more cant to the bow I didn't want to change my style, not thinking how that would effect the bare shafting. Thanks!

[killinstuff]

You can try drawing 27" and if they fly good, underspined and then draw 29" fly good, you're over spined.

[Shawn Leonard]

David, I bet cut to 29.5"s they are weak with even 125 head. I go by Kelly Petersens charts(now Foxfire archery) He says add 10-15#s to bows weight at your draw for high performance recurves cut past center and than add another 5#s or so for the inch over 28's, so in your case I bet ya need 75# spine or a tad more with that 125 grain head! Shawn

[snag]

I cut them to 28.75" and put 145gr tips on them and DID NOT cant the bow and they hit 2" right of center at 10 yds. I will try again tomorrow. Might have to try 125gr tips or cut down another .25".

[Dr. Ed Ashby]

If they are 2" right at 10 yards, it's going to take a fair increase in dynamic spine to bring them over that much. Shawn probably has it right.

Ed
TGMM Family of the Bow

[smilinicon]

raise the nock point until you show tail high, then lower it a little at a time until it goes tail left again and you will find a sweet spot where it shoots dead straight.

I fine tune my POC when I dip the shafts. If I need to stiffen, I hold the shaft by the point end and if I need to soften the spine, I dip point first while holding the nock end. I should note I use water-base sealer and when the sealer drips sown, it will add weight to one end or the other. If I like my bare shaft flight, I can dip each each end to the middle of the shaft, then both ends will get the same drip amounts.

I used to tune by changing arrow length, but I now like to cut my arrow to length (28" for me), lightly glue on my nock and tip, bare shaft, sand the shaft if too stiff, then remove the tip and nock for dipping evenly on both ends.

I don't do this for all arrows, just the 'special' sets I want to be perfect. As stated earlier, be mindful of false readings from slapping.

Nocking point and dynamic spine are set by watching arrow flight and no chart or guideline will ever be as accurate.

hope it helps.

Cary

[snag]

How about building out the shelf plate to bring the arrows in to the bullseye? I will try the 125gr points. They if they are still showing weak a little could I build out the side plate?

[snag]

If this doesn't get where I should be I might have to use these with a 52# recurve I have coming...?  (52#+15#+5#=72# instead of 55#+15#+5#=75#)

[Shawn Leonard]

David in wood 1/4" should not even be notucable. 1/2" will be but mqan ya got to have a clean release to notice. Kelly's charts are usually very, very close. I will also say 2"s at ten yards is tough to tell as well, if ya move just a tad at release 2"s is not that much! Shawn