Time to make arrows

[DC]

OK I screwed up. I assumed that the same FOC would equate to the same tip weight as far as dynamic spine was concerned. I was wrong. The next arrow was a couple pounds lighter and I put a 100 grain point on it. It went straight in from 3 yds out to 15 or so then it started to drift. I'm happy again. Now I can experiment with it a bit.

[DC]

I reduced the spine 10#to 47#, reduced the tip weight from 100gr to 60 gr. and it  flew about 2" nock left. I shortened the arrow an inch and it's still a tad nock left. It weighs 377 gr.

[Woodely]

I think you should experiment making at least a close to center shot bow.  I just make the arrows around 38-45# spine.  Some arrows fly great from certain bows and others fly better from other bows. 

Basically I match the bow to the arrows and spend time tuning the bow not the other way around.  It just gives me more flexibility when making arrows as I just wing it so to speak.   An arrow that may fly right/side on one bow will fly straight on another.

[DC]

To me, centershot bows have always looked like they were one pull away from breaking. I'm slowly sneaking in

[ohma2]

Im not going to say its gospel but im shooting pretty light weight bows to and i havent had one break yet taking the rest area to near center shot. Look at some of Mark st. Louis bows and you'll notice he gets them very close to center shot and he is building bows alot heavier than what im using.

[TSA]

so sad to see all that work broken.
if you would like i am sure i could find a piece of sitka of appropriate size to send down to you.

Bareshafting is a scary moment with ANY wooden shafts.
if i can offer any advice it would be to start waaay close to the target, and start trimming- i have attached a bareshafting video- its the best  i have yet seen, its in the link below.

i made the same mistake- years ago when i started bareshafting, i figured if i got back far enough, the energy left in the arrow would be reduced enough that it would not break the shaft, how wrong i was!!! they are so far out of alignment by the time they get to the target- that they break off- even if they are only a bit off- it surely makes one realize how important a job the fletching does!

its counter intuitive- if you start really close- the shaft is not that far out of alignment when it impacts the target, so doesnt snap off as easily, then slowly work your way back.
yes the "paradox" does effect it a bit, but it works, i start at 3'

another way is to get the shafts close, but a wee bit long, get them all fletched up- the start broadhead group tuning- even if you dont plan on hunting, even though its a grouping exercise, i still shoot one shaft at a time- thre field points, circle the grouping, then 3 broadheads circle the grouping, and start trimming until the groups are one.
http://www.trueshaftarchery.com/tuning-the-bow.html

[DC]

I've watched that video many times and yes, it's good but his first shot is just an inch or so off. He had the spine very very close before he took the first shot. That's where I'm having the problems. Getting it close to start with is tough. Especially when you're fiddling with weight. Everything seems to be based on a tip weight of 125 grains and I would like to use a lot less than that. If I want to use a 50 gr tip that should mean that I should spine my arrows 15# lighter(I think) That's a big jump. Thanks for the offer of wood but I'll look around here first. I hate the idea of putting money in the shipping companies pockets. If there is anyone that makes money off the internet it's them. I'll check the dry land sorts first. I got that nice old growth hemlock from them, maybe they'll have some spruce.

[Woodely]

A professional arrow maker says that he tapers the last 10" of the nock end having more FOC and claims this helps big time.  I have started doing some tapering but not that much. What you guys think.. ?

[DC]

It's supposed to make them more forgiving of spine. I've always shot bamboo which comes pre tapered and when ever I made wood arrows I tapered them to get rid of weight without affecting the spine so I've never shot parallel arrows to compare it.

[TSA]

Woodely,
i have cut and pasted this from some info i am starting to collate for our website.
its very disjointed, and in point form...kinds!
but there may be some info in there that you can use.
also here is a link to a page that does some very technical analysis of back tapered shafts.
for the longest time , i have always attributed the improvement in performance to the increase in FOC, but it goes a lot deeper than that.

this link was posted on this forum a little while ago, i found it fascinating and highly informative, so we made contact with the original author, and acquired his permission to publish it on our site.

http://www.trueshaftarchery.com/technical-information-1.html



and heres the "cut n' paste"

FOC

Low is 0-7%
Normal 7-12%
High 12-19%
Efoc 20-30 % - (extreme  FOC)
UEFOC 30% +  (ultra extreme FOC)

The greater the foc, the stiffer the  spine required
The greater the foc, the longer the control arm, the smaller the fletches required
Higher foc will effect long range trajectory- closer to 0% foc will improve long  distance trajectory- this has to do with the angle of attitude of the projectile changing as the velocity reduces in flight.

EXAMPLE
50# longbow @28” = 50-55 shafts
Cut to 30.25” to give a length of 29”to BOP
With 125gr pt
With 11 gpi shafts (380gr@34”)

Will produce a 500 gr finished arrow or 10gr per pound of draw.

Will give FOC of 13%

           HOWEVER
taper back 9” to 5/16 will give FOC of 14.3%
Taper back and add 200 gr pt =FOC of 20%




Weights on arrows.
3 x 4” fletches -10gr
3 x 5.5” fletches -13gr
Glue – 3gr
Snap on 11/32 – 17gr
Snap on 5/16 – 12gr
Urethane finish - 6gr per coat
Cap wrap – 10gr
Cresting – 5gr

Remember: adding weight to the back of the arrow, will make the arrow behave stiffer

Tail taper reduces weight of shaft by 8-10gr ( 11/32 to 5/16 over 9”)

reducing weight on the back- improves FOC, but also makes the arrow behave weaker


Lightest scenario-
fletches – 10gr
Glue     -  3gr
5/16 nock -12 gr

tail taper (subtract 10 gr)

total rear mass of 15 gr

Heaviest scenario
Fletches - 13 gr
Glue - 3gr
11/32 nock -17gr
Cap wrap - 10gr
Cresting – 5gr
Total rear mass of 38gr       that’s 2.5 times heavier!!!!
that’s a 23gr difference.

[Woodely]

Thanks for the info.  So what would you recommend to take down these shafts to about 5-7# less.  They are currently about 48# spine.  30" from base of tip to nock groove AMO measurement.  I'm thinking of doing a back taper and I always use 125gr. tips but I could go to 145gr.

[DC]

Good post Wayne.

[Pat B]

Lightly sanding the center 1/3 of the arrow would lighten the spine. Rear tapering would not decrease the spine but will make the arrow more tolerant of draw weight.  When I was learning about making cane and hardwood shoot arrows Art Butner taught me that with the natural taper of these shoots and canes you can subtract as much as 10# from the actual spine value. The commercial Tonkin cane arrows don't have much taper so it probably isn't the same with them.

[TSA]

i concur with Pat- the middle third controls the spine. we do find that when putting back tapers on shafts- up to about 8" doesnt effect the spine at all, every extra inch seems to drop the spine by about 1#- and thats just a ball park- i cant say at what point it starts to compound- as its been years since i did a full length tapered shaft- i did some in the early days- maybe i should try that again and record the info

[TSA]

Woodely, as Pat said you can lightly sand down the center third- and that will reduce the static spine of the shafts- so thats the spine thats measure on a spine tester.
 The dynamic spine is how the shaft performs, and this is an area where one can fudge things a lot!
heres an example> a #50 static spine- as they come measured from the manufacturer is assuming a 28" draw and 125gr points_ but go up to 150 gr points now your 50# spine shaft is actually behaving like a #45 spine shaft.
there are a lot of things a person can do to effect the dynamic spine.
1.play with point weight and length of shaft
2.reduce or add weight to the rear will do quite a bit, but it works in converse to point weight. IE: adding weight to the back will stiffen the dynamic spine.
now adding weight to the back may not be the best scenario, but reducing weight will weaken the dynamic spine, a back atper will help with that a lot- so will reducing fletch size etc- as you saw in my post above.
sometimes just putting on a cap wrap will stiffen a shaft quite a bit!- the vinyl wraps weigh about 2gr per inch.
3. you can also play with the bow strike plate- building the strike plate out will make the bow want a weaker spine shaft- so if your shafts are a bit stiff, getting your arrow to pass closer to center- by maybe putting a thinner strike plate on- will make the bow want stiffer shafts- and it doesnt take much- sometimes just adding a layer or two of double sided carpet tape can drop the spine by #5. Or going from a thicker leather strike plate to a thinner strike plate can push the spine requirement up by #5
4.you can mess with the brace height, but i dont like to do this- you can take a nice shooter and make them darn ornery- i get my brace height where i want it and leave it- then start to play around with the other variables.

or you can just build some new shafts, but thats not as much fun, and one doesnt really learn as much!!
cheers- good luck