spine tester

[jdwilltx]

Has anyone ever seen or used this?

http://www.jamesmhill.com/Spine_Tester.html

I want a spine tester but dont want to spend alot.  Is this worth a try?

Jeremy

[stiknstring]

Lots of guys have built it....search the archives here and over on tradgang's site and you will find lots of jim hill fans....

[jdwilltx]

His is set at 26 inches.  I think I will make mine 28 and just rework the spreadsheet with the deflection and spine.  Cool!  Thanks!

Jeremy

[stiknstring]

Someone posted a reworked spine sheet for 28 and 30 inch spread on the tester....run a search!  no sense in reinventing the wheel if you don't have too

[jdwilltx]

Anyone know where thats at.  Havent found it yet.

Jeremy

[Kegan]

I built one, and it's quite accurate, but I get better results just shooting my best current hutnign arrows from a bow, and tweaking the bow as I'm building it to make it shoot the arrows better. But I make most of my arrow the same way, so it's easier to tune the bow than the arrows .

[Justin Snyder]

It is set up with a 26" space, but it is calculated to give you the spine of an arrow 28" long.  Unless you are using barreled or extremely tapered shafts, it wont make a difference to you.  I recommend you build it the way it says and use it, I did.  Justin

[zLego]

Yes, this working fine! See you this:

http://www.my-bow.hu/?q=node/824
http://www.my-bow.hu/?q=node/1109
http://www.my-bow.hu/?q=node/1027

http://www.kaltokri.de/index.php?option=com_content&task=view&id=12&Itemid=8

[jdwilltx]

Thanks zLego.  I ordered my dial indicator, should be here today. 

Jeremy

[Badger]

One thing worth noting is that at .5 deflection the dial indicator is pushing back against the weight about 8 oz almost 1/2 pound. At .7 deflection it is pushing back even harder. Makes a considerable difference in the actual spine you are getting. I am sure dial indicators vary a little but the ones I checked were pretty close to that. Steve

[Justin Snyder]

Steve, I have a dial indicator that goes to 1" without even registering on the scales. I just got lucky I guess.  Justin

[DanaM]

You lost me on this, do you mean to say the dial indicator puts up 8oz of resistance at 0.5"
Hmm now I have to devise a way to measure the resistance and subtract it from the reading. Correct?

[jdwilltx]

I took one apart yesterday that I have here at work.  It has this little spring in it.  I have been trying to think of how to remove the spring and still make it work.    Maybe the spring could be stretched.  It seems like it would be easier to do that than to subtract the resistance from the reading.  The one I ordered was a cheap one so maybe it will not have any resistance. 

Jeremy

[jdwilltx]

I think I figured it out.  Actually zLego figured it out.  Look at the first picture he posted earlier in this thread.  The dial indicator is upside down yet the plunger is hanging down.  So he must have removed the spring.  So you just set the arrow under the plunger and on the stands.  Zero out the indicator and put your weight on.  No resistance at all!  This should be very accurate.  Now I just wish my dial indicator would show up.  I am tired of waiting!

Jeremy

[Wasatchhawk]

I bought a dial indicator at Harbor freght last saturday for $7.95.  I don't know if they are still on sale or not.