increasing carbon arrow weight, foc, and footing - UPDATE

Rob DiStefano · November 02, 2009, 12:17:00 PM

just another method for upping carbon arrow weight, foc and front end durability ...

carbon shaft weighting - UPDATED 11-3-09

arrow without point, before adding weight tube ...

arrow without point, after adding weight tube ...

DesertDude · November 02, 2009, 12:44:00 PM

Hey Rob, Thanks for the info.....

wingnut · November 02, 2009, 01:07:00 PM

Rob,

That's pretty slick!! How much did it reduce the spine? Your notorious for being able too shoot noodle spined arrows and some of us don't have that good of a loose.

LOL

Mike

vermonster13 · November 02, 2009, 01:16:00 PM

How does the tube stay in place when you hit something hard Rob?

Rob DiStefano · November 02, 2009, 01:50:00 PM

QuoteOriginally posted by wingnut:
Rob,

That's pretty slick!! How much did it reduce the spine? Your notorious for being able too shoot noodle spined arrows and some of us don't have that good of a loose.

LOL

Mike

geez, i dunno mike - i gave away my spine meter 2 years ago, LOL!

seriously, learning how to 'aim the arrow' and working on a fluid release will really free up any dependency to worry about shaft spine ratings. coupling that with really high foc will make hunting arras more efficient and deadly (with an emphasis on 'dead').

i added over 100 grains to the bemans i tested, and though i'm sure there's got to be a change in spine due to the weight tube, that added weight is distributed for a good 4" behind the ferrule.

Rob DiStefano · November 02, 2009, 01:52:00 PM

QuoteOriginally posted by vermonster13:
How does the tube stay in place when you hit something hard Rob?

when the arrow ends it flight by smacking into something, the weight tube further pushes into the point ferrule. the tube will not move backwards unless you push it out.

THE WEIGHT TUBE MUST FIT TIGHT INTO THE SHAFT!

there are lotsa variations to be tried with this kinda weight tube.

vermonster13 · November 02, 2009, 01:55:00 PM

Very nice job Rob.

BenBow · November 02, 2009, 05:43:00 PM

I do something similar but use a 4 1/2" 8-32 redi-bolt screwed & glued into the back of the insert. To keep it quiet & fine tune the weight I wrap it with duct tape. Easy to add 100 to 125 grains.

Rob DiStefano · November 02, 2009, 05:57:00 PM

QuoteOriginally posted by BenBow:
I do something similar but use a 4 1/2" 8-32 redi-bolt screwed & glued into the back of the insert. To keep it quiet & fine tune the weight I wrap it with duct tape. Easy to add 100 to 125 grains.

yeah, went that route years ago - hard if not impossible to fine tune.

Hud · November 02, 2009, 06:33:00 PM

"when the arrow ends its flight by smacking into something, the weight tube further pushes into the point ferrule. the tube will not move backwards unless you hook it and pull it out."

Sounds like a good idea, but what keeps the weighed, tube from sliding to the nock end, when the arrow is launched if it is not glued in place, especially since you can hook it and pull it out?

Is the reason you do not glue the weight in place, because your changing weights?

Rob DiStefano · November 02, 2009, 06:44:00 PM

QuoteOriginally posted by Hud:
... Sounds like a good idea, but what keeps the weighed, tube from sliding to the nock end, when the arrow is launched if it is not glued in place, especially since you can hook it and pull it out? ...

friction fit of the weight tube holds it in place. the only dynamic force of concern applied to the weight tube is when the arrow ends its flight, then the weight tube is forced forward.

Ragnarok Forge · November 02, 2009, 09:19:00 PM

Rob,

Thanks for posting this. I am working up some high FOC arrows and was wondering how you put so much weight up front without going to a super heavy broadhead. I will keep this idea in mind while working up my arrows.

ozy clint · November 03, 2009, 12:28:00 AM

i've been doing that for the last 12
months. :cool: i didn't realise i was at the forefront of arrow technology!

for my gold tips i use the white 8gr/" weight tube from 3rivers. i found that 4mm steel rod fits inside perfectly. (4mm welding rods with the flux removed)

i hold mine in by putting the lighter black weight tube behind it, (3gr/") for the rest of the arrow.

Rob DiStefano · November 03, 2009, 06:27:00 AM

QuoteOriginally posted by ozy clint:
i've been doing that for the last 12
months. :cool: i didn't realise i was at the forefront of arrow technology!

great minds think alike? :D

Rob DiStefano · November 04, 2009, 08:58:00 AM

after a buncha testing, a few of the weight tubes popped the nocks out or shifted position.

the fit of the weight tubes MUST be TIGHT!

i've updated the pictorial page to show how i create tight fitting weight tubes ...

weight tube UPDATE

PEL · November 04, 2009, 10:15:00 AM

Very nice - I have been doing something very similar but I love the cut off nail! I also add 1.5 inches of aluminum arrow on the OUTSIDE of the carbon shaft - it keeps the insert from being forced into the shaft and shatering it! I think the resulting graduated nature of the arrow's stiffness also helps protect agains breakage! Great minds think alike!

Ragnarok Forge · November 04, 2009, 11:53:00 PM

Rob,

Thanks a bunch for posting this. You just saved me a ton of time and money, since I was planning to start working on finding out how to do what you showed in this post.

A couple of questions for you. How are your arrows doing as far as durability? I am presently shooting the Axis FMJ's in 500's with 275 up front and they are standing up to some serious abuse. I am curious how the straight carbons are holding up when you are hunting.

Another question, how wide of a head weight band can you shoot with the same shafts? As you vary the head weight are you shortening the shafts to adjust the spine or are you just changing the head weights and calling it good enough to hunt.

Again I cannot thank you enough for posting this for all of us on the EFOC quest to utilize. Just another example of why this site and the trad gangers on it are awesome!

Hud · November 05, 2009, 02:10:00 AM

Rob,
I appreciate your taking time to go thru your setup with so much detail. It is a great help for someone that has not experimented with internal weighting to achieve maximum FOC.

My questions relates to the weight of your broadheads (667 gr) and your practice arrows with field pts. Is there a difference and does it matter and what is your solution?

For example, are you changing the internal weights? If the Wensel is 174 gr. of the total 667 grains, what is the makeup of your field arrow and do you have to re-tune? I am thinking if you drop 125 gr. more or less the arrow is not going to fly the same. Answer anyway you prefer. Thanks

Rob DiStefano · November 05, 2009, 08:03:00 AM

QuoteOriginally posted by Clay Walker:
Rob,

Thanks a bunch for posting this. You just saved me a ton of time and money, since I was planning to start working on finding out how to do what you showed in this post.

A couple of questions for you. How are your arrows doing as far as durability? I am presently shooting the Axis FMJ's in 500's with 275 up front and they are standing up to some serious abuse. I am curious how the straight carbons are holding up when you are hunting.

haven't hunted with them yet, but will next week on a hog hunt. i've tweaked the arrows a bit more, adding more weight for a total arrow weight of 660 grains - 250 total point weight and 410 in the shaft and weight tube. been shooting the heck out've all 18 arrows, using carefully weighed judo points, at 5 to 32 yards. so far, so good.

Another question, how wide of a head weight band can you shoot with the same shafts? As you vary the head weight are you shortening the shafts to adjust the spine or are you just changing the head weights and calling it good enough to hunt.

for me, i see no difference in arrow flight outta the 55# mohawk, at any shot distance. i think this is due in part to my overall form, release, the 8 strand string, the build of the arrows, and the forgiveness/stability of the mohawk. 'hunting form' is important, along with a smooth release ...

it's VERY IMPORTANT to take the time to get these weight tubes fitted SNUG, TIGHT into the carbon shaft. adjust the masking tape for a fit that will allow you to ram the weight tube down into the carbon shaft with pressure. i test each newly hatched weight tube arrow with a full draw release into a block of foam at 5 yards.

Again I cannot thank you enough for posting this for all of us on the EFOC quest to utilize. Just another example of why this site and the trad gangers on it are awesome!

mighty glad to oblige, it's what trad gang is all about, sharing stuff about trad bowhunting.

worth repeating ...

it's VERY IMPORTANT to take the time to get these weight tubes fitted SNUG, TIGHT into the carbon shaft. adjust the masking tape for a fit that will allow you to ram the weight tube down into the carbon shaft with pressure. i test each newly hatched weight tube arrow with a full draw release into a block of foam at 5 yards.

Rob DiStefano · November 05, 2009, 08:27:00 AM

QuoteOriginally posted by Hud:
Rob,
I appreciate your taking time to go thru your setup with so much detail. It is a great help for someone that has not experimented with internal weighting to achieve maximum FOC.

My questions relates to the weight of your broadheads (667 gr) and your practice arrows with field pts. Is there a difference and does it matter and what is your solution?

For example, are you changing the internal weights? If the Wensel is 174 gr. of the total 667 grains, what is the makeup of your field arrow and do you have to re-tune? I am thinking if you drop 125 gr. more or less the arrow is not going to fly the same. Answer anyway you prefer. Thanks

i'm VERY careful to match arrow weights. i weight all points, adapters, weight tubes, feathered and nocks shafts, on a digital scale. i can get overly ocd about all that. i'll grind the back or front of a judo and/or adapter to hit the right total weight. i haver every size and material imaginable of field points, judos, adapters. i even add a nut to screw in adapter to add 5-15 grains, if need be. my broadhead of choice is the woodsman, and *almost* all of my arrow testing is done roving style using judos.

ANYTIME you mess with arrow weight and/or foc, you will at least need to see what it's done to arrow flight elevation. that's a given.

if you think about upping foc, the best place is at the point itself, since that's furthest from the nock. these nail weight tubes add more weight behind the screw-in ferrule, so it's not as efficient as going heavier with the point, adapter, ferrule.

for example, these 660 grain arrows i just built are using 45 grain aluminum ferrules - i also have the same shafts set up with 100 grain brass ferrules, and loading one with a weight tube gets me over 700 grains (which, btw, fly just fine for me :D ).

it all comes down to what you wanna achieve. for me, that's first and foremost to up the entire arrow weight from my usual 585 grains. why? well that hog i shot in june used a 585 arrow tipped with a hair shavin' woodsman and it didn't pass through, though it did clip the lungs and tickled the heart. never found that arra, either.

so, firstly i'd like to go with a heavier arrow that i can control at hunting distances (up to around 25 yards). second, if i'm gonna add weight i want it up front to add to the foc. why? i believe foc aids in penetration and i love hog hunting.

the down side of added foc could be, and probably will be, a weakening of spine. can you and yer bow handle it? only you can answer that question. or, as one trad ganger has done and posted on this thread, use a weight tube AND a spine tube to both add foc and increase the arrow's spine.

interestingly, after LOTS of shooting with these weight tubes, i'm now beginning to believe they don't detract from spine in any noticeable dynamic way. but that's for each of us to decide.