3Rivers Archery



The Trad Gang Digital Market












Contribute to Trad Gang and Access the Classifieds!

Become a Trad Gang Sponsor!

Traditional Archery for Bowhunters






LEFT HAND BOWS CLASSIFIEDS TRAD GANG CLASSIFIEDS ACCESS RIGHT HAND BOWS CLASSIFIEDS


« previous next »
Pages: [1] 2   Go Down

Author Topic: How accurate is the 'dynamic spine calc.' ?  (Read 903 times)

Offline Mr.Magoo

  • Trad Bowhunter
  • **
  • Posts: 701
How accurate is the 'dynamic spine calc.' ?
« on: January 21, 2010, 05:18:00 PM »
I'm fiddling with the 'dynamic spine calculator' and am a bit surprised by the results I'm getting.  

I'm plugging in the specs for my Bob Lee Hunter TD (55@29 and 3/16 past center, at least I think it's 3/16 past center) and I'm getting a dynamic spine of 78.1.  Sounds a bit high to me.

I know 2018's will fly fine from this bow, but on the calculator they're not even close ...
Logged

Offline mmgrode

  • Trad Bowhunter
  • **
  • Posts: 1314
Re: How accurate is the 'dynamic spine calc.' ?
« Reply #1 on: January 21, 2010, 05:35:00 PM »
Is your bow a longbow or recurve?
Logged
"We are what we repeatedly do. Excellence, then, is not an act, but a habit."  Aristotle

Offline Mr.Magoo

  • Trad Bowhunter
  • **
  • Posts: 701
Re: How accurate is the 'dynamic spine calc.' ?
« Reply #2 on: January 21, 2010, 05:36:00 PM »
recurve ....
Logged

Offline soopernate

  • Trad Bowhunter
  • **
  • Posts: 553
Re: How accurate is the 'dynamic spine calc.' ?
« Reply #3 on: January 21, 2010, 05:37:00 PM »
The calculator's 3/16 is FROM centershot not PAST centershot....could that be your issue?
Logged
I humbly follow in the learned footsteps of those who precede me.

Offline wtpops

  • TGMM Member
  • Trad Bowhunter
  • ***
  • Posts: 2323
Re: How accurate is the 'dynamic spine calc.' ?
« Reply #4 on: January 21, 2010, 05:41:00 PM »
If the bow is cut to 3/16 past center then you need to subtract the strike plate thickness. If it is 1/16 then you put on -1/8 if it 1/8 thick then you put in -1/16. Their is always the human factor also
Logged
TGMM Family of the Bow
"OVERTHINKING" The art of creating problems that weren't even there!

Offline saumensch

  • Trad Bowhunter
  • **
  • Posts: 915
Re: How accurate is the 'dynamic spine calc.' ?
« Reply #5 on: January 21, 2010, 06:06:00 PM »
Now im interested!
does that mean if i have a bow that is 1/16 thicker build than the center, i substract the 1/16 of the strike plate and get to pu 0,0 in to the calc?
Logged
And sometimes our dreams they float like anchors in hopeless waters oh way down here
Sometimes it seems that all that matters most are all the things that you can't keep
(William Elliot Whitmore)

Offline xtrema312

  • Trad Bowhunter
  • **
  • Posts: 3163
Re: How accurate is the 'dynamic spine calc.' ?
« Reply #6 on: January 21, 2010, 06:51:00 PM »
Forget the riser cut.  It doesn't matter unless you don't have anything on the riser.  If the strike plate material face is 1/16" outside the string center or that much farther away from the riser then the center of the string it is +1/16.  If it is 1/16" inside the center of the string or closer to the riser than the center of the string it is -1/16".  I don't know anything about Bob Lee bows, but -3/16" sounds like a lot cut past center to a strike plate.
Logged
1 Timothy 4:4(NKJV)
For every creature of God is good, and nothing is to be refused if it is received with thanksgiving.

Firefly Long Bow  James 4:14
60" MOAB 54@29 James 1:17

Michigan Longbow Association

Offline NDTerminator

  • Trad Bowhunter
  • **
  • Posts: 1181
Re: How accurate is the 'dynamic spine calc.' ?
« Reply #7 on: January 21, 2010, 08:56:00 PM »
From using the calculator, IMO it's darned accurate.

I use a piece of rug rest rather than a leather strike plate  on my Lee TD Hunter, and it's -1/16".  It's 52#@28", I draw 28.8", use FF string, and it has a calculated dynamic draw weight of 69.6.  I built several test arrows based on that draw weight to a calculated spine within 1#, and they shoot beautifully.

Based on that, and assuming you draw at least 28" & use FF, you might well be in the mid 70's, but I agree 78 & change seems high...


The calculator drop down box has both +/- center cut settings, BTW.


Hope that helps...
Logged
"As Trad as I wanna be"

"It's all just archery, and all archery is good"

Offline wtpops

  • TGMM Member
  • Trad Bowhunter
  • ***
  • Posts: 2323
Re: How accurate is the 'dynamic spine calc.' ?
« Reply #8 on: January 21, 2010, 09:11:00 PM »
Quote
Originally posted by saumensch:
Now im interested!
does that mean if i have a bow that is 1/16 thicker build than the center, i substract the 1/16 of the strike plate and get to pu 0,0 in to the calc?
If your bow is cut past center you subtract side plate thickness if it is cut to center or thicker then you add side plate thickness.

If you bow is cut 1/16' before center and you have a 1/16" side plate you put in 1/8. The main thing is to put in actual center mesurement, dont forget to add or subtract side plate thinkness
Logged
TGMM Family of the Bow
"OVERTHINKING" The art of creating problems that weren't even there!

Offline Mr.Magoo

  • Trad Bowhunter
  • **
  • Posts: 701
Re: How accurate is the 'dynamic spine calc.' ?
« Reply #9 on: January 21, 2010, 09:37:00 PM »
Thx guys.  I have a weatherest on the bow I'm monkeying with so I probably have the wrong center shot variable plugged-in.
Logged

Offline hayslope

  • Moderator
  • Trad Bowhunter
  • ***
  • Posts: 1630
Re: How accurate is the 'dynamic spine calc.' ?
« Reply #10 on: January 22, 2010, 10:23:00 AM »
Overall, I think it is a very accurate tool to use.  I tried it out a few months ago on some new CE carbons for one specific bow. Fletched arrows were spot on.  Bare shafts grouped spot on as well, but were nock right, indicating stiff.  Had some folks tell me to ignore the nock right since they grouped tightly with the fletched shafts.  Fletched up the bare shafts and never looked back.

I've also recommended the calc to another guy and provided my own suggestions.  This guy had been having fits trying to match carbons to his very short draw BW.  He used it and had a bow shop put the arrows together to the calc's specs.  Spot on right out of the box.......another convert!
Logged
TGMM Family of the Bow
Compton Traditional Bowhunters

“Only after the last tree has been cut down…the last river has been poisoned…the last fish caught, only then will you find that money cannot be eaten." - Cree Indian Prophesy

Offline screamin

  • Trad Bowhunter
  • **
  • Posts: 470
Re: How accurate is the 'dynamic spine calc.' ?
« Reply #11 on: January 22, 2010, 09:17:00 PM »
I was playing with it the other day and put in all the specs including the arrow I found flies best out of my bow. It nailed it, and the amazing thing is it hit the speed to within 3fps!
Logged

Offline xtrema312

  • Trad Bowhunter
  • **
  • Posts: 3163
Re: How accurate is the 'dynamic spine calc.' ?
« Reply #12 on: January 23, 2010, 11:26:00 AM »
I think it is more accurate than my form.  It needs a few bad form boxes for me.
Logged
1 Timothy 4:4(NKJV)
For every creature of God is good, and nothing is to be refused if it is received with thanksgiving.

Firefly Long Bow  James 4:14
60" MOAB 54@29 James 1:17

Michigan Longbow Association

Offline daveycrockett

  • Trad Bowhunter
  • **
  • Posts: 1501
Re: How accurate is the 'dynamic spine calc.' ?
« Reply #13 on: January 23, 2010, 11:53:00 AM »
Just finished tuning a new to me bow. After deciding on my shaft and point weight went and plugged all the info in. My arrow combo was within .1 of requred spine. Pretty dang close!! 66.4 required and 66.5 the arrow I put together.    :bigsmyl:
Logged

Offline daveycrockett

  • Trad Bowhunter
  • **
  • Posts: 1501
Re: How accurate is the 'dynamic spine calc.' ?
« Reply #14 on: January 23, 2010, 04:00:00 PM »
up
Logged

Offline Possum2

  • Trad Bowhunter
  • **
  • Posts: 139
Re: How accurate is the 'dynamic spine calc.' ?
« Reply #15 on: January 23, 2010, 04:10:00 PM »
I shot a indoor tournament last night and tried a specific arrow and had the best scores ever never shot the arrows before  :banghead:  Went home plugged in the # and I was .5 difference in spine deflection can't get much better than that!
I like thae calc. just so I can play around and fine the best set up with enough FOC to my likeing.
Logged
Martin Jaguar 60" 50@28
RER Vortex longbow 62" 46@28
Zipper Extreme 60" 55@28

Offline Tyke

  • Trad Bowhunter
  • **
  • Posts: 66
Re: How accurate is the 'dynamic spine calc.' ?
« Reply #16 on: January 23, 2010, 04:27:00 PM »
Where can a guy find this calculator?
Logged
only those who attempt the absurd, achieve the impossible.

Offline zmeister

  • Trad Bowhunter
  • **
  • Posts: 10
Re: How accurate is the 'dynamic spine calc.' ?
« Reply #17 on: January 23, 2010, 04:36:00 PM »
Here's the link to Stu's page where you can download it.  http://heilakka.com/stumiller/
 I, too, think it is pretty darned accurate.
-Z
Logged
May the good Lord keep you and your arrows flying staight and true.
-Z

Offline Tyke

  • Trad Bowhunter
  • **
  • Posts: 66
Re: How accurate is the 'dynamic spine calc.' ?
« Reply #18 on: January 23, 2010, 04:43:00 PM »
Thanks alot "z".
Logged
only those who attempt the absurd, achieve the impossible.

Offline daveycrockett

  • Trad Bowhunter
  • **
  • Posts: 1501
Re: How accurate is the 'dynamic spine calc.' ?
« Reply #19 on: January 23, 2010, 06:22:00 PM »
Just weighed my components, my is dead nuts.
Logged
Pages: [1] 2   Go Up
« previous next »

Users currently browsing this topic:

0 Members and 1 Guest are viewing this topic.
 

Contact Us | Trad Gang.com © | User Agreement

Copyright 2003 thru 2024 ~ Trad Gang.com ©