4 Fletch Bouncing off shelf

[2nocks]

Hey Guys, I read a bunch of the four fletch posts on here and picked up some 4" parbolics in the classifieds. I've fletched up a few 1820 aluminum shafts with 75x105 and 90x90. They both seem to bounce off the shelf the 75x105 more so than the 90. My 3 fletch wood and carbons do not bounce so I haven't moved my nock height yet.

 Wanted to post a few pictues and see if it looks like they are aligned ok or if maybe its another tuning issue I should sort out.    

[2nocks]

75x105  

[MCS]

Turn your knock 90 degrees. That should help.

[Scott E]

I would say go ahead and raise your nocking point and see what that does. It probably will help the ones that are bouncing and probably wont hurt the ones that arent bouncing.

[Rock 'N Bow]

Have you considered a 2 fletch set up? I read a recent article in Traditional Bowhunter where the author fletched only the lower outer vane and the upper inside vane. Even vanes didn't make contact with the shelf or strike plate and achieved great arrow flight. I've been considering this myself so I can still shoot vanes in less than ideal weather conditions.

[BOWMARKS]

On the 75 - 105 I would turn the nock 90deg. on the 90-90 would not make a difference.

[2nocks]

Thanks guys. I'm going to just raise it and turn the nock on the 75-105. Of course they're swaged end aluminums with glue on nocks    

[Tajue17]

1820 alums what weight you shooting just want to be sure its not spine,  anyway when im tuning an arrow like and aluminum or wood where you cant turn the nocks i will only use a tiny drop of glue on the nock so i can break it free if ithe fletch is catching and rotate it more once i find what the bow likes i glue it up good.   Finally make sure your shelf is not velcro and make sure you put extra dabs of glue over the front of the quills.

[Hermon]

[The Whittler]

I have done 60-120 with a right wing Jo-Jan and it worked great.

[2nocks]

Tajue i tried them out of a 45 and a 50 pound bow.

[Herdbull]

I have shot 2219 with 4 x 5 inch Right Wing feathers mounted 75 x 105 with nock aligned as you have shown for 30 years. But I did notice the quill would eat away at the outer edge of the shelf. I elevated half of the shelf (basically the width of the arrow) about a 1/4 inch, then cutting a slit in the shelf matterial and laying the outter edge back flat to the shelf. This extra clearance worked wonders. It also help with additional clearance when wearing a heavy glove during cold weather for bows with very tight shelf to grip style. Mike

[2nocks]

Thanks Mike.  I'll have to give that a go also.

[wingnut]

I'd sure shoot a bare shaft out of the bow also to make sure it's the right spine and alignment before assuming the problem is the fletching.

Mike

[Hud]

The theory is more drag, faster correction, but it can result in greater feather wear.  Sprinkle some Tac or baby powder around the window, rest and shelf to see where it is hitting. Also, agree with Wingnut, that  shooting a few bare shafts is a good idea to check spine.

[JimB]

I agree with Wingnut.Did you shoot those arrows before the 4 fletch?That's a heavy walled shaft and may be too stiff.It might be worth adding 25-50 grs of point weight and see what happens.I've never had 4 fletch cause any bounce.

[2nocks]

I haven't shot them before. I tried 100 and 125 gr points. And I tried 200 gr. 200 gr basically crashed and burned, made the problem much worse. Maybe somewhere in the middle would help.

[wingnut]

What are the specs of the carbon arrows that fly well from the bows?  Also what are the specs of the 1820s  Length etc.?

Mike

[2nocks]

3555 with 175 up front, have weight tubes fly well. Cut to 29. 2016 cut to 29 fly well, I can shoot 145 or 175 in the 2016 without a noticeable difference. a 5575 arrow with 275 up front also flies well. not noticing any proposing. These are all 3 fletched.

[wingnut]

Ok, now I see the problem.  The 2016 that fly well have a dynamic spine of 52-56 pounds.  The 1820 has a spine of 40.  That's a big difference.

The 1820 is way underspined for this bow.

Mike