Trad Gang

I designed an AMO spine tester so I can start making wood arrows and this is the second iteration to improve things a bit.  This tester is 2.0 pounds at 26 inches per AMO standard.

(http://i169.photobucket.com/albums/u230/cupcake1000/TesterR2a.jpg)

I have improved the scale to also read deflection as well as AMO spine.  This deflection is not the same as Easton, et. al., report because they measure spine using 1.94 pounds at 28 inches.

(http://i169.photobucket.com/albums/u230/cupcake1000/TesterR2b.jpg)

The second improvement is adding a ball bearing assembly to the pivot point for the pointer.  The first version used a bushing arrangement that was OK but had a bit of stiction.  I think the weight applied from above, directly atop the pivot arm is a bit better than hanging a weight from the shaft.

(http://i169.photobucket.com/albums/u230/cupcake1000/TesterR2c.jpg)

Tell me what you think.
Kevin

Looks Great

Looks good! Curious,how do ya zero your pointer for different diameter or, uhh, err, crooked arras?
I really like the weight on top too!

On the left arrow support is a thumbscrew adjustment that zeros for different shafts.

Ok, now start making them for sale, I will be first in line. I like it better than my store bought modle.

Danny

Good lord! That's the finest looking homemade spine tester I've ever seen. Great work!!!  :thumbsup:    :notworthy:

Well Kevin,  you have come along way "Grasshopper" Very fine.....  Sorry I missed you all this weekend.  the deflection is a great addition. I want one .......we'll talk at breakfast..........Mark

I love it.  I'll be second in line.  Just wondering, why don't wood arrow manufacturers, shaft sellers just go to the Easton deflection standard?  Since most of us these days are coming from carbons and aluminum back to woodies?

Wow!
Kevin, that's some nice work! And I love your attention to detail! This spine tester should fit into every living room without disturbing the view of the "better half" in your life. Clever planed and done!  ;)   :D
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Quoteposted by Cutty47:
why don't wood arrow manufacturers, shaft sellers just go to the Easton deflection standard?  Since most of us these days are coming from carbons and aluminum back to woodies?

"Easton Standard"  :confused:  ???????    

Not ALL are comming "back" from something!
IMO those who had/do turn back - should not ask the "ridgid ones" to adjust to their new point of view, but get themselfs back to the good old sights.
Ahh, I don't know if I got this accross now - somehow difficult for me to explain ...

Falk, I'm not sure about you, but if you take your accuracy seriously, you bareshaft...

Ever try bareshafting woodies?  Don't work so well...

Sooo, any whooo...

Matching aluminum deflection to the same deflection in wood saves you a whole bunch of money in the long run.

I love bows.  Bows cost money.  Hunting trips cost money.  Poorly spined arrows are firewood.

People get discouraged buying expensive firewood.

People stop buying woodies.  Woodie dealers go out of business.

The "rigid" ones can find woodies anymore.

Have to go to Easton deflection anyway...

I've never even seen a simple chart comparing common aluminum arrows with wood arrow poundage.

Besides, demystifying and standardizing the wooden arrow spine is going to do nothing but bring more people back to shooting wood.

Think about it...with the advent of glass laminations, R/D bows, and especially FF strings, some sort of change should have been made...

All of this add five pounds for a "modern recurve," add another five pounds for "FF string"...add five more pounds for hardwood shafts over cedar because they don't recover as quickly, add another five pounds if your bow is cut close to center...

...so, I need an #80 spine out of a #67 LB?  Or is it a #75 spine?  And what about poplar versus chundoo?  What about hickory versus Ash?  And are hexpine shafts hardwood?  And how does laminated birch behave compared to hexpine?

Can you tell I've been trying to make the transition?  Lol...

nice looking set-up  :thumbsup:

You want a little cheese with yer wine!
I have no trouble bare shafting wooden arrows.
Nice spine tester Cupcake. Makes my homemade job look like it was made in the landfill.

nice work Kevin, i'm in line for one as well.

wha did you use to print that metered chart on a curved plane like that??

Some software I've not seen before?

I know I'm setting myself up as a complete computer fool..but it doesn't bother me because I am...so tell me, please..how you printed that way?

High quality craftsmanship. Do you have an idea what you spent in materials to build it?

Cutty, here's a simple spine chart for ya:  http://www.arrowsbykelly.com/Spine_Charts.html

That's a slick tester!

Thanks Jeremy, I refer to that chart quite a bit.

Apologies for the rant...just finished a dozen POC and after shooting them I think they're underspined.

Cutty, Now you have a new project.  Build you a bow to match your arrows.  Then you get another bow and you get to keep your arrows out of the fire.  

I would be willing to bet you could sell them if bowbuilding is not an option.  But you know that already.

Nice work! If you make them they will sell...

"I want one" looks briliant would you consider making any to sell and how much

I'll take one.

Very impressive!  You have done your homework  :thumbsup:    :thumbsup:  ...Van

Quote"Easton Standard"  ???????
 

Agree with Falk.  Folks always trying to fix stuff that ain't broke....Van

First class job on the spine tester

Thanks for all of the compliments on my spine tester.

I want to answer some questions that were asked.

For Ray - the software I used was AutoCad, a drafting design program.  Everything is simple triganometry.  I printed on a laser printer.

Falk and Van/Tx - I said Easton standard only because I was in a hurry.  I believe most arrow manufacturers use the American Society for Testing and Materials (ASTM) Standard - 28 inch support span, 29 inch arrow shaft and 880 grams (1.94 pounds) weight.  The deflection of the shaft is reported from this measurement.

The Archery Manufacturers and Merchants Organization (AMO) standard is 26 inch span and 2.0 pounds.  The AMO spine is then 26/deflection.

By the way, tha AMO has renamed itself the Archery Trade Association (ATA)

I have translated the spine measurements of Easton aluminum arrow shafts to the AMO spine by using beam deflection theory.  I have tested as many Easton shafts as I can get my hands on and have verified that my translation is correct.  I will hopefully be able to post this info when I get more time.

Kevin

Kevin,

Very impressive piece of equipment you put together!!

However, I do have a comment/question  

When has Trig EVER been SIMPLE?  :confused:    :)

Ok Kevin now your just showing off!!!!!  Kevin joined our group of stick bow shooters awile back. I thought he ws a bit strange at first till he told me what he did for a living,  yep you guessed it....."Rocket Sciencetist" or somthing very close to it.  This guy has some real talent.... Picked all our brains (what little we have) about Traditional Archery, he's like a mop. great job on the tester, and oh ya...I want one...... DesertDude

Forget the spine tester, when are you going to start taking bow orders? Lol...

Cutty,
Bows are on my list of things I want to try but I have this wild hair to perfect a spine tester first.  Then I need to start making wood arrows.

Desertdude has been a great friend and mentor in trad archery and I think I can lay part of the blame for my love of this sport on him.

Kevin

Cutty,
yes, I do bareshaft my woodies! And of course it works! Why not? And, if you think about it, it would make any spinetester unnescessary if we were not to lazy to do it for every shaft ... !
Your bow is a spine-tester after all! Better so: a tester for dynamic spine!

I don't argue about the "add 5# for FF, minus 10# for 2" of stringfollow" etc. thing! No! I agree totally here!
But that's not the point! AMO standard is also measured by deflection - only later translated into pounds - for convenience of the customer.

Don't read your spine in pounds and only thing you have to do is find yourself shafts with a deflection of, say .325" - or somewhere close to it. Done!
And it is of NO help to force new "standards" into existing fields. WHY change the old 26" 2lbs. standard? Now you have to know both! Now you have to look very carefully each time, as not to mix them and by which you order shafts etc. And make sure the pro shop owner also knows the problem. Big confusion!

  :wavey:  
Falk

Put me in line for one Kevin if you decide to manufacture.  I'll trade you a batch of wood shafts (probably have to be a big batch).

Good looking craftsmanship!

Dennis

Falk,

You're right.  Thanks for educating me on the fact that AMO standard was first measured in deflection, then translated into pounds.  I love the wealth of info on this site.

Personally, I haven't had the same luck bareshafting woodies as compared with carbons, or aluminums, and I know of quite a few archers, much more accomplished, and experienced than I who don't believe in bareshafting woodies-- Paul Brunner comes to mind.  

But I'm certainly not dismissing your personal experience, and if it works for you I'll bet you have a heck of a release.

Hey Kevin, have you given anymore thought to making the scale fold down for storage? I was real impressed with your whole project. Not only were to able to design the tester but you did a real great job crafting it.
See ya Sunday, Tom M.

Tom,
I worked on that a bit last night and it will be incorporated in the design in the future, not hard to do.
Til Sunday,
Kevin

:thumbsup:  good looking spine tester   :thumbsup: