need plans for a spine tester

[Trapper Rob]

I'm looking to find out how to make a spine tester.
Rob

[RBLusthaus]

I suggest that you Google 2 Jays spine tester. 

While there are many DIY spine testers out there, I built the 2 Jays version, and I am very happy with it.  While it might not be dead on, it is consistent, which is really what spine is all about.   A rose by any other name, and all that.

Russ

[Fred Arnold]

I purchased the materials for this one but have never completed it. I already have a Spine-O-Meter and always keep finding other projects that need done.

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

[Guessed]

Thanks for posting that link, I was wondering how "bow poundage" works with it. Measure deflection then divide 26 by that amount. The answer is how much weight the arrow can take.

"Ahah," I said to myself.

[RBLusthaus]

The answer is how much weight the arrow can take.

Not sure what you mean by that, but the spine of an arrow and poundage of the bow do not necessarily align for perfect arrow flight.  Many other factors come in to play, such as arrow length, point weight, and how far off center shot the bow is, just to name a few.

Russ

[Fred Arnold]

Depending on the reading of your spine tester, 26 or 28 on center, if you leave the arrows 28", you should be close enough to shoot poundage of your bow at your draw length. A lot of variable though and RBL is correct. I've shot 45# spine and 75# spine arrows out of my bows between 50 and 55#'s bows. Best way to start is find an arrow that shoots good out of your bow and work from there.

[Trapper Rob]

When you make arrows do you spine them or just shot them to see witch ones fly best.
Rob

[RBLusthaus]

When I make arrows, I do spine them, but when they are completed, I shoot them to see which ones fly best. 

Hows that for double talk.

Since I make my own shafts - I keep them sorted them by spine groups.  When I make arrows, I take the doz or so from the spine group that think is right, make the arrows, and then test them.  The spine groups are just a starting point for me.  Testing how they fly is most important.     

Russ

[Trapper Rob]

Russ do you make your arrows from shoots or do you take square pieces & plan them down.
Rob

[Guessed]

"Safely take before 'exploding?'," at least that's what I figured out anyway lol. My (carbon  ) arrows I broke by shooting them from my dads "bow." It's metal and has wheels. Apparently the arrows are 'safe' between 45 and 60 lbs, his bow is a 90 lb bow. It shot them so hard it broke the backs and stripped the (plastic) 'feathers' off of them.

Anyway, I got the equation I wanted lol.

After clicking the link (and the bamboo arrow thread) I wondered: why 26 inches? Now I see 28 is also an option. By 'center' what is meant? Like the middle of the arrow length wise or the middle of the arrow 'thickness' wise?

[RBLusthaus]

Rob

Currently I am making a set from some kind of bamboo given to me by Youngbowyer2.  I am sure he will chime in with where he got them.  Someplace in Fla I think - - some crazy ridiculous low price for 500 sticks, I think.  Most spine kinda high, so some judicious sanding was / will be in order.   

That said, I usually make them from wood boards.  Poplar, ash and pine are my most frequent woods used, although maple and cedar are great as well.  From boards to 3/8 square sticks, to rounds sticks, then to burnished shafts, then they get footed, if I am doing footings (which is not often as it is so time consuming, but they do look great.)  Shhhh!!!!  Dont tell anybody, but I am going to give a hip quiver and 6 footed arrows for the Xmas trade - so I will have to foot some more shafts soon enough.     BTW, Do you know what spine and arrow length XXXXXX shoots? 

I don't use the plane down method except for the footings.  I use the veritas doweler (the cheap one) and burnish with some hard wood scraps (red oak or hick as it is always laying around).  I use an old drill and socket set to spin the shafts like a lathe.  If making thousands of shafts, this is probably not the best method, but it works well for me.  When I make shafts, I usually make about 4 dozen at a time and end up culling about half. 

I have never made arrows from shoots, although it is on my list of things to do.  I am really enjoying working the bamboo shafts, but they are way more time consuming.  Only time will tell if I like them better, but from others on this site, I think I will like them just fine. 

Russ

[RBLusthaus]

Guessed

The spine of an arrow is more a function of how easy the arrow will bend around the riser when shot from your bow and less a function of how easy the arrow will break if shot from to high a poundage bow.   That said, shooting a 25# arrow from a 130# warbow is asking for trouble.

All things being equal (and they never are, are they?), an arrow with a 40# spine shot from a RH bow will end up in the target to the right of the same bow shooting a 60# spined arrow, as the lower spined arrow will bend more around the riser thereby ending up further to the right.  Reverse for LH bows.  This is simplifying things a bit, but the concept remains the same when you start to factor in the other variables which mess with the effective spine versus static spine. 

The best way to prevent an arrow from exploding on you is to look at the grain of the shafts and cull (make a tomato stake from) any shaft with lots of runout.  If some runout must be present in the shaft, orient the runout to run away (towards the point) on the top side of the shaft, so if it does break, the back end will go up and away from your bow hand.     

I hope this helps you. 

The 26 v 28 inch standard is for wood v carbons, I think.  Someone will correct me if I am wrong.  They sell the carbons based on a different spine standard.  There is a conversion chart around, I think. Yes, you hang the 2 pound weight from the center of the shaft and measure the deflection. 

Russ

[Trapper Rob]

Russ
I made 2 out of viburnum they shot very well don't know what the spine was on them first arrows from shots I ever made have some wild rose ready to make just have to take time make them I get them finished I'll post pics of them.
Rob

[Fred Arnold]

Long long time ago, far far away, I was introduced to barrel tapered poplar shafts and I purchased a gross of them full length in different spine. And then  I started building bamboo natural taper shafts from the garden stores, And then I found japaneese bamboo from Jaap (Yumi Bows).
There are a lot of tremendous arrow building materials available that work fine and dandy but for hunting arrows I still use my tapered poplar (Superceders) and Mr. Kopedrayers bamboo shafts. 

[BowEd]

Trapper Rob.....I went ahead and bought the book Bow Accesseries written by Volkmar Hubschmann sold I think in the 3 Rivers catalog.The book cost thirty dollars but there are a number of self do it projects in there.
The spine tester he shows how to make uses a measuring dial used in metalworking to measure circular tolerances.I bought a digital dial that has a button to instantly zero it out to measure each shaft.Very quick & accurate.The dial cost about twenty dollars.The rest of the spine tester is made from extra scrap pieces of boards laying around.Most times they want way over 100 dollars for a spine tester.He also shoes a graph you can copy and tape it to the frame of your spine tester that you can instantly read what spine your shaft is.
I think he's German so the measureing is done in mm.No problem with a dial that measures that too.
Up to you a lot of em work good out there.This one is quick and easy to spine arrows compared to most.No math to do or resetting to zero out etc.Math was not my best subject in school but learned to get good at it farming all of my life.