Failures

[Kidder]

I thought it would be interesting to start a thread on bow failures and why they fail. I know we all want to see the successes but it’s probably way more important to analyze the failures than the successes. In particular late stage failures where the bow is shooting or close and somehow fails. I’ll go first.
Here is a boo backed Osage bow that fretted on a tiny pin knot that popped up on the side of the limb. During the built the pin showed itself. I tried to get under it and thinned it too much. Rather than leaving it thick I left it thin trying to get rid of it. There is no visible hinge (or wasnt) and it’s been shot probably 1000 times but it’ll likely fail at some point. As a result of this experience (and another involving a boo yew) I’ve decided that I much prefer flat sawn boards for board bows - that way any pins run back to belly opposed to across the belly.
Let’s see some other failures and the analysis of “why”.

[bjrogg]

Great idea kidder.

I know I have certainly learned from them.

I’ll have to look back and see if I can find some pictures.

Bjrogg

[Hamish]

It's still probably got plenty of life left in it. Keep an eye if it starts to hinge or if the chrysal gets longer, then you know it's on its way out.

The only ways you can get around those knots is to leave a compensatory lump on the belly from the start of tillering, or cut out the section and inlet a new piece of osage.

[bjrogg]

I couldn’t find any pictures, but my first bow definitely thought me some lessons from my mistakes.

It was a White Ash flat bow. I actually did a half ways decent job making it. The tiller was far from perfect but it was probably long enough and a short enough draw that I think it would have survived.

It had a little twist in it and I was sure that it needed to be removed. So I had two little propane torches. Myself with one on the belly and my brother with one on the back. I was going to heat it up like a piece of steel and get that twist out.

It still somehow survived for a couple weeks but it developed a hinge where the back was scorched.

I however had total confidence in it.

I took it to a neighbors shop that a bunch of old timers friends of mine had coffee at every Saturday morning.

They already kinda thought I had a screw loose with all my flintknapping and bows & arrows stuff.

I was as going to show them

I strung my bow all the while they were saying don’t do it it’s going to break.

I drew it to my normal anchor a couple times and everything was fine. Then with total confidence I drew it to my ear and heard craaack. Followed by a shop full of laughter.

Yeah I learned several lessons from that one.

Bjrogg

[bjrogg]

One time I made a really sweet little ash bow for my grandson. It was tiller really well and the little arrows that I made for it flew like darts.

I decided to cut an arrow shelf in it for my grandson to be easier for him to shoot. As I finished the shelf and picked up the bow to string it I realized I had the shelf on the wrong side. Still looking for a left handed kid who can use a 15 lb bow.

Bjrogg

[simk]

If you dont't make them you don't brake them 

Even small pins and knots can ruin the nicest laminate. Indeeed the strongest argument against edge grained laminates. As mentioned a patch will save that bow in case its getting worse Kidder...

Not sure if I can patch this one tough....

This one was ready tillered and pulled to 110# @ 33"  a few times. I called it good, made and polished the nocks and tought I could get rid of the very small amount of set (and maybe gain a few more pounds) with a gentle heat treating. DON'T DO THAT ON HEAVY YEW WARBOWS! It was a perfect stave, very good and careful build and tiller imho....goodbye @ 108# @ 31"...

https://www.youtube.com/watch?v=Ev79ThFuhkQ

Always keep your heads up 

[M2A]

Fall of 2019 I was working on a piece of American beech. Target weight was 50 lbs at 27". Had it tillered out to 26 or 27"(been a while), but had put a few arrows through it and it was real close to shooting in. Bottom limb was starting to take on a little string follow, 1/4" or so. I could not notice any thing wrong with the tiller and it shot good, but figured the top limb needed a few scrapes to even things out. but it was almost ready to start to shoot in. 
IMG_3286 by Mike Allridge, on Flickr
IMG_3293 (2) by Mike Allridge, on Flickr

Not the best pics but is what i have. Maybe when I get home tonight I can get find this bow and go into the rest of the story with some more pics. So ill leave it at a cliff hanger till I can do that.
Mike             

[superdav95]

Ya I’ve had failures.  Even exploding ones.  Here’s a good example of a few rookie mistakes.  This was from a couple years ago with a yew wood recurve bow.  The stave was decent but had some dog leg bend and twist in it one one end.  I was able to heat bend them out for the most part with oil and dry heat.  I believe I over did it though and made the bow too brittle.   Also to blame it the bad tiller choice on this one.  I decided to go for a more elliptical shape for my tiller and didn’t do a very good job with it and the top limb was stressed too much in the outer 1/3. The bottom not as bad but stressed as well.  I learned from this bow and remembered to only heat correct an area once and only as much as needed and not ask too much of the wood.  The tiller choice was not wise either on this and so I found out that the combination of the two errors caused an explosion of the bow.  It was like a gun went off actually. 

[bjrogg]

Looks like about a 9.9 on the pucker factor Dave.

Bjrogg

[superdav95]

Looks like about a 9.9 on the pucker factor Dave.

Bjrogg

Yup it was!  Just lucky that it didn’t come back and hit me in the face and take my eye out. 

[Kidder]

This one takes the cake for me. This stave has resisted being a bow from the second I laid eyes on it. I’ve still managed to get about 200 arrows through it though and it shoots so dang well I hate to let it win.
It started with heat bending. The stave had reflex out of the handle on the top limb and deflex in the lower limb. So I decided to use dry heat to take out the deflex. Except I used too much clamping pressure and not enough heat and caused a tension break in the belly resulting in a hinge that I’ve been chasing ever since which has now caused many tiny frets. Then I was recurving the tips and threw a splinter. Chased that away but it wouldn’t hold its shape so I used some thin yew strips to make an underlay. Turned out nice and really holds the recurve. Then I applied sinew to the bow. Put the first layer on, applied some reflex with a string and left it on the counter overnight. Somehow it fell and broke the tip nearly clean through. But that didn’t stop me. I injected TB3, clamped it and did a sinew wrap. Finally a couple weeks ago I decided I wanted to try to chase the hinge away so strung it to check the tiller, took a couple draws, and BANG! The sinew layer’s delaminated! So it wins and gets to be a wall hanger. For now at least… I guess I’d rather break the same bow 4 times than 4 different bows 😂

[M2A]

Took a while to find some of that beech as it was buried deep in the corner of shame.
However after the above pics and maybe 20 F/D shots I wanted to take a few scrapes from the top libs to even things up. The bow blew up on the tillering tree in my shop that night. It wAS  duck and cover type moment as the top limb went in several directions. Looked at the scale afterwards and it was showing the max weight was 58 lbs i think and I know it was still a few inches short of full draw. No excuses other than I was not paying attention to the draw weight as much as I was trying to have a good tiller. Think things would have been ok at 50 lbs but should have had a target weight more like 45lbs. Combined with trapping the back on a wood that is already a bit weak in tension. It was a good reminder to pay attention to what your doing.   

IMG_5327 by Mike Allridge, on Flickr     

[Marc St Louis]

How about this one

[bjrogg]

Certainly not the Full Draws I’m use to seeing from you Marc.

A little confusing but I’m thinking a belly delaminating?

Bjrogg

Awesome picture though.

[bassman211]

Over the years I have dam near filled a 55 gallon drum with broken bows, but in the last 10 years I have broken very few. Belly frets count as broken to me also. I use them for tomato stakes.