The tricky arrow spine

Courtesy of the “Instinctive Archery MAGAZINE” (
Especially for wooden arrow shafts it is most important that the arrow matches the bow and archer, so that it can be used perfectly. The spine of a wooden shaft is the starting point to find the right arrow for a bow.The archer usually depends on their dealer’s precise and truthful information about that.
At Bearpaw Products, the spine of wooden arrow shafts is measured with the latest technology. According to Henry Bodnik, founder and CEO of Bearpaw Products, this “Spining system” is a one-of-a kind unit and guarantees precise arrow spines. Henry allowed us a backstage sneak peek and explained his new device to us.
Uwe: Henry, what was your intention in constructing this machine? What gave you the idea?
Henry: There were always discussions about the spine value of wooden shafts. All devices for “hobby section measuring”  produce more or less diverging results.
That is because these are just devices for the “hobby section”.
Therefore it was necessary to set a new standard. Up to now, all wooden arrow shafts were hand spined in a complex procedure at Bearpaw Products – and you can certainly imagine that  we process and measure a lot of wooden shafts!
It was a real challenge in the past to do a precise measuring of this huge amount of shafts with our old arrow spine station.
Uwe: This new machine looks huge! I’ve never seen anything like it before!
Henry: This arrow spining station is really one-of a kind! Some time ago we had the former CEO of Goldtip here for a visit, he was visibly impressed by this machine.
Even a technician from the USA was sent over to test the machine and its possible application for GoldTip, but in the end they found it too expensive.
This here is a special construction, in my opinion a masterpiece of German engineering.
Uwe: Where was this machine constructed?
Henry: The machine was developed by a German technician. I gave him the important information about the functions and parameters it should have. Working together with an engineering company here in upper Franconia, we could then implement this ambitious project.
Uwe:  Could you explain the individual work steps and the capability of this “arrow spining machine”?
Henry:  With pleasure! Of course it is a complex and comprehensive procedure.
Here we have the first workstation. The wooden arrow shafts are put into this container and  get transported to the second processing position, which is the spining process. Here the wood shafts get separated. Because it occurs here and there that the shafts aren’t positioned properly, the machine has an ejector that puts the shafts back into the collection container.
Following we get to the most important processing at the second workstation. Here the wooden shaft gets spined, they are measured by ATA standard.
Here the shaft is rolling onto the gaging station and  gets properly positioned. Afterwards, it gets a deflection with 2lbs. This deflection is measured and acquired by a computer.
In the next step it gets  turned around 1/3 of its circumference and is measured another time. All in all the wooden shaft gets measured three times.
The measuring of the deflection – which actually is what “spining” means, is done with the latest laser technology. The computer takes the highest measured spine value  as the basis for further processing. Then the shaft gets ejected and rolls onto the next, the 3rd work.
Here the straightness of the arrow gets measured, also via laser technology, to get exact results. Now the right spine value of this wood shaft gets printed on in a 4th work step. Therefore, a high-quality ink printer was integrated into the machine.
Then a gripper arm swoops for the wood shaft. In that arrow spine machine, a Siemens computer is integrated to control and steer the correct processing and allocation. The wooden shaft now gets transported to the matching box for its spine.
To manage this, there’s a sorting agent integrated in the spine machine, to make sure all different spined shafts get stored in the right box.  The spine machine automatically switches to „fault modus“ when one of the boxes is filled with the max. amount of 10 arrow shafts.
All shafts which aren’t assignable are stored in a collecting box.
Uwe: So the wood shafts gets completely automatically measured and controlled here at Bearpaw!
Henry: Well, not all completely, in the very beginning of the process there is still handwork required. Before the wood shafts are placed in the 1st workstation, they get controlled for the correct plankwise run of the wood grain, which is done by an employee. Only if the wood grain in the shaft runs straight and consistent, it can be used as an arrow.
Uwe: I am absolutely impressed by this system! How would you describe the purpose of this machine with just a few words?
Henry: Here a wooden round stick gets refined to an arrow shaft!
We are proud that we are selling our wood shafts all over the globe. Wooden arrow shafts made in Germany.
Uwe: Thank you so much for taking the time to explain this impressive machine to us!
Henry:  It was my pleasure, Uwe.  
It’s  important for me to make processes here at Bearpaw HQ transparent and share them with the archers.
By the way, if you want every 3 months exclusive reports, articles, news about instinctive archery,
I strongly suggest you the “Instinctive Archery MAGAZINE.”
An edition for 5.99 € or 4 for the price of 19,99 €.
Worth it !!