Spine tester

[mzombek]

I wanted to share a spine tester that I just finnished up. It took me several months and 3 pilot testers, but I finaly completed.
The accuracy is dead on using 2216 and 2315's
 


 


 

[darin putman]

Looks nice I was trying to figure out how to zero then I think I saw it on the left side. Curious about weight does it just push straight through from the top, looks as though it would be a pretty consistent design. Good job!!!

[Matty]

Super nice

[Ray Lyon]

That looks slick.

[Bjorn]

Bingo! What a great job! Where do we order?

[Stumpkiller]

Simple and elegant.  Very nice work.

[picapica]

Nice!  I'm working on the same thing - how did you compensate for the return spring in your dial indicator?  Do you do it by adding equivalent weight or with your calculations?

Mark

[mzombek]

Darin,A bolt with the head cut off to contact the arrow and the thredded end of the bolt into the weight. I tried to use linear bearings and found that as long as the weight sits on the arrow straight,that is all that is needed.

BJORN, How many do you want?

Mark, I was not concerned with the pressure of the spring. I used the 2 pound weight, pulled down on the stem of the indicator. When the weight pushed the arrow as far as it could I gently allowed the indicator to just touch the shaft, did that 3 or 4 times for repetabilty and took that number to cross refference.

Since you are using a 2# weight, does that mean your outside points are 26" apart?

Good job! I paid #200 for my commercially made tester!

Bisch

[chall]

I like it , been wanting to do one myself too.

[mzombek]

Yes, 2# with 26" outside point

[mzombek]

I have about 40 bucks in it

[BOWMARKS]

Some of you guys are pretty handy "nice work".

I had to part with $200.00 also Bisch

[Caughtandhobble]

Thanks for posting... I have been shooting wood arrows some lately, I have been contemplating making one.

[Lucas K]

Nice work, are you making any for sale?

[mzombek]

Lucas,
If I get some interest in folks wanting to buy, I could make a few.

[Bob Morrison]

I'm interested, let us know price you want?

Bob

[chall]

Im interested too, let me know how much $

[tecum-tha]

Nice, but way too complicated with a dial indicator like that. And the accuracy is not better than a pointer indicator model either. Problem is, most likely you have to compare the measured deflection in inches to the spine from a table. If you spine any number of shafts, you will soon hate this "feature" of this kind of tester.
Building a good spine tester should take you about 2 hours, another hour is needed to draw the correct scale and about 30min to cast the weights. About 30 dollars worth of home depot materials. I think someday I have to make a tutorial how to build one.

[mzombek]

Tecum, I did not build this unit for speed nor did I reference to other spine testers. I checked 17 woodies last night that I purchased from John who owns Twigg archery. I don't know his method, but 15 out of 17 arrows that I checked were the same he got. And you are correct, it will take a little longer than the fixture that you speak of. I made this fixture for the 3 to 4 dozen of shaft that I buy a year. Apparently you test hundreds of shafts at one setting, I do not.