Let's Tune Some Carbons!

[John Scifres]

OK, back at it.  I am following OL Adcock's method, as posted above, as much as I can.  My philosophy on learning is to find good instruction and follow it really well the first time I do something before I start ad libbing.  Then again, sometimes I just flounder through and use trial and error.  In this case, OL seems to have some clout so we'll go with that.  Here's the direct link.

  OL Adcock on Tuning

[John Scifres]

My first goal was to set up the bow as proscribed by the instruction.

 

I started with the string silencers.  These were set by dividing the string into thirds and placing them there.  In my case, 17.5" from the ends of the strings.  OL said said to set them halfway between the tips and the centers so I guess I didn't follow religiously  

 

Then made sure my arrow rest and sideplate were right.  I added bits of toothpicks under the existing rugs to adjust.

 

I then had to sand the nocks to make them less snug.  And then on to adjusting brace height.  I started at 7-1/8".  According to OL, you should adjust from the lowest brace recommended by the bowyer and then shoot 4 arrows.  You then raise it until you find the spot where noise and vibration is minimized.  For me, I got to 7-7/8" and it seemed real tight.  As I got above 8", the vibration and noise got worse so I backed it down to 7-7/8".

Now on to the real tuning.

[fnshtr]

Good stuff here John...

Thanks for taking us along.

Wayne

[Flatstick]

John,,,I got bit by the curiousity bug this year too! All the reading and talking to many about carbon arrows got to me. I've made and shot arrows of aluminum, wood, saplings, and cane but always shyed away from the carbons until just a few weeks ago.

I know, I know carbons out of a homemade selfbow! But I just had to try it. I've ended up with full length (30")carbon express 250 "pile driver" with 300 grains up front. Talk about penetration, it is a very noticeable difference. The arrows are bottoming out my old scale at 650 grains, I'm going to have to borrow a friends digital scale to get a true weight.

I'm definately going to follow along this thread, we both have that "what if I do this" kind of curiosity I think.

[John Scifres]

OK, here is what I came up with.  I cut the arrows down to 28.5" and shot the crap out of them all day.  I got my brother over here and he shot a bunch too.  In the end, the arrows at 28-1/2" with 250 grain points shot the same bare shaft as the did fletched.  And they shot better than I could.  Here is the last group.

 

 

I had a few flyers in every group but they were consistently mixed between fletched and unfletched.  In fact I would say I was more consistent with the unfletched shafts.  They flew great most of the time.  Here is a typical good group without the flyers.  Mixed bag betweeen fletched and unfletched.

 

I'd be happy to hear thought on this.

[Looper]

Two questions. What distance did you shoot from? Are you nocking above the nock?

From the looks off those groups, your nock might be a touch low. Anytime you're fetches group larger than your bare shafts, it's likely that you're having some fetching contact.

I suspect you are nocking above the nock, but if you aren't, add a lower one.

[John Scifres]

I am shooting at 15 yeards.  I am nocking below the nock.

[Looper]

Okay, first, add a second nock below the arrow. Leave a little gap so the nock doesn't pinch at full draw. Even with correctly fitting arrow nocks, the arrow will slide down the string upon release, so you want to eliminate that.

I'd also recommend using tie on nock sets, too. They are a lot easier on your gloves, weigh less, and it's easy to make adjustments when necessary.

Once you get the two nocks on, go back and shoot again.  Start at 15 yards, like before. If, after a couple of bareshafts, you are hitting the center of the target, go ahead and move back to 20 yards. Take you time between shots, and shoot at least 6 shots with both the fletched and bareshafts. The longer distance will make any needed adjustments more visible.

[John Scifres]

OK, I did as Looper recommended and also sanded my nocks on several arrows I forgot to do that on. In the end, I got pretty consistent with the shooting.  At least as consistent as I have ever gotten.  The bow is quiet and the unfletched shafts shot as well as the fletched shafts.  The 2 nock points definitely helped.  I only have 15 yrds to shoot in my back yard.  I have a shoot planned for the 25th so I'll get some longer distances in.  

I learned a lot on this and no doubt have a better mathced dozen arrows than I have ever had before.  They lack the warmth of wood but they make up for it in shooting.  I really like them.  I still won't shoot carboons from my selfbows but the glass bows I unt with most will surely use them.

[John Scifres]

I weighed my arrows this morning and they come in at 525 grains.  That's a bit over 11 grains per pound.  They fly pretty fast at 15 yards.  I'm curious what they look like at 20+.

Balance point is at 21.75 from the nock groove. My overall length without the point is 29".  If my math is right, that means an FOC of 25%.  Someone check me on that.  If I include the point length, the FOC is 21%.

[jess stuart]

Thanks for the info John.  I too got some of the 1535s from Big Jim, didn't really know where to start. They have been laying on my desk for a week or so.  Have always used wood or alumn just time for the old dog to try and learn a new trick.

[John Scifres]

I haven't shot them yet but with the 100 grain adapter and 190 ribteks, the FOC approaches 30%.

Jess, I have been shooting these out of the recurve you made me.  I am quite sure at least one of them will end up flying through an Indiana whitetail this fall.