Why did these Douglas firs break all of a sudden?

[Benny Nganabbarru]

A couple of days ago, I was shooting a cardboard target on the oval. These blunt-tipped arrows are what I do all my target practice with, and they simply punch through the cardboard and arrest in the lawn beyond. As I drew back on the 75# @ 28" Wesley Special, I noticed the arrow seemed to be unusually bent towards the tail end. I let down, and examined the arrow, noticing a hair-line crack which then easily broke the arrow in half with very little effort. I examined the other arrows, and they seemed fine. Not too long after, I made a good shot on the cardboard, and as the arrow punched through, I noticed the back half break off and go in a different direction to the front half. This arrow had broken in the middle.

These Douglas fir arrows are 30" BOP, and wear 160 grain blunts. They are spined 95/100# and I shoot them out of both the 75# Hill and the 65# Black Widow PCH. This combination works well on the game, and the broadheads fly true. I've been shooting this combination for a few years, now.

I don't recall how old the arrows are, but I'd say they'd be at least a year old. I suppose they've hit quite a few termite mounds as well as dirt banks and the grassy surface of the oval. I suppose each one has been shot hundreds of times.

What do you reckon? Upon impact, there is some flex from what I've seen in slow-motion movies, as well as upon release as it bends around the riser. Would this repeated stress cause the fracture? I have never experienced this before, and I've shot a lot of arrows stump-shooting.

 

 

 

 

[Benny Nganabbarru]

Occasionally, a termite mound is encountered that is rock-hard, and the arrow bounces back off. I always check carefully after these shots, and flex the arrow, but have never found fault. Perhaps I should discard arrows after hard impacts, even if they look fine.

[ChuckC]

Those look like they were broken over ones knee, at least most of the way.

Did you upset somebody recently ?
ChuckC

[Shedrock]

Wow, very odd. I never seen that before.

I have several cedars and doug fir that I have shot for years at bunnies and stumps. I can't seem to break them or even lose the darn things.

[Pat B]

That is from deflections off of hard objects. It is a hair line crack across the grain and hard to detect sometimes unless the finish breaks too. If you have any questions about a wood arrow, break it immediately!

[Hermon]

I had a poc break like that this summer. Never did figure out why.  The shafts had some age on them, but had just been made into arrows a few weeks earlier.

[Hud]

That does seem odd. It sounds like the blunts are hitting and bending causing the fracture in the grain.  I would either try a different target, like a bale of hay, or put some field points on and see if they pass thru cleanly; especially if the card board is thick.

Check them close, before shooting again.

[magnus]

I agree with Pat. When you strike a hard object that energy is going to take the path of least resistance. In this case up the arrow shaft. After several hard hits the shaft became stressed and cracked. Field point might help some. Just my 2 cents.

[David Mitchell]

Ben, I had some doug fir that were too dry a few years ago--maybe too long in a kiln or something--but they were very brittle and broke like that.  I discovered how brittle they were when I tried to straighten one by bending it over my hand a bit and it just snapped.

[Troy Breeding]

The only wood shafts I ever had do these type breaks was DF. I think it's like David said, too dry for some reason or another.

Troy

[JINKSTER]

Yep...i'm no wood arrow guru but..i know the results of dry wood when i see it.

I shot wood arrows when i was very young and as i recall?..when i did break them?..they'd break in a very elongated fashion with both broken ends looking like long shards..because they broke "with the grain"...those puppies there?..they broke straight across the grain..and imho?..there's only one way that happens...

"Dry Fibers"

[Charlie Lamb]

They've been stressed in some manner Ben. Possibly mishandled in shipping aand had something heavy set on them or the package took a hard bend.

Other than that you might have had something fall on the group or quiver.

I had it happen when I was a boy to a dozen Forgewood Battleshafts (compressed cedar), and it broke my heart. Each shaft showed a bend at the spot where it broke prior to breaking.

[Ric O'Shay]

Ben -

A cross grained break like that does show signs of stress at that given point on the shaft. That coupled with really dry wood would contribute to the clean break.

Danny

[Bill Carlsen]

I made custom wood arrows for a number of years. Fir made a good arrow unless it was too dry. My best guess is that that is what is happening to you. Fir gets very brittle  after a while...just the nature of the wood. They do make beautiful arrows but I have always questioned their longevity. I certainly would not use a water based finish on them.

[Benny Nganabbarru]

Thanks, fellows. Most educational! So, between a hard life and dryness / brittleness, their time came?

[Jim now in Kentucky]

It's been said from long ago that Douglas fir gets "brashy" if it's too dry. Even at that, those breaks are way cleaner than normal.

I'm guessing your area is extremely dry, right?

Jim

[ChuckC]

I am thinking that a break like that right behing the point is relatively common from deflections,  but back there, either they were damaged from something else, or maybe your shot into a termite nest was thru brush and when it struck and vibrated, it hit brush hard back there ?   I can't imagine a break like that . . back there. .  just from deflections.
ChuckC

[Javi]

I've had DF, SS and POC all break clean like that just hand straightening right out of the box.. usually because of a cross grain stress like a dent or compression from a lick against something..

[Raminshooter]

Ben,

As you have seamingly already discovered it is a combination of factors but the defining one are the "hard hits" on those occasional super hard termite mounds.  As that shock wave passes through the shaft towards the nock end it has a tendency to focus in an area where there is the slightest compromise to the wood already.  I have seen shafts break like that is some weird examples:  in one case the shaft broke clean accross just below the nock even though the nock did not make contact with anything!  In another, the shaft split clean down the middle from point to nock as if you have sliced it with a razor!  Bottom line is that only mother nature knows how that piece of wood was put together.  Have fun and thanks for sharing.

[Benny Nganabbarru]

Thanks again. This has been very informative for me. Jim, my area can be really dry in the dry season, but now is the wet season.