Why are my bows breaking?

[Soren-dk]

Hi
(Sorry for typos and wierd phrases,- I'm Danish)

I've had three bows break on me in a row. After the one last night snapped, I was sure I'd never want to make another bow again. I bet you've all tried standing there stomped, with two pieces of useless stick, but I do hope your failure ratio is better than mine..
Ive worked on some 10 self-bows, but Ive only got 4 left and they're pretty weak. The rest broke on me with a big bang.. So with that ratio, I must be  doing something wrong..
 
This is how I go about making bows:
I collect wood in a forrest near by. I dont cut down fresh trees, but take home some of the large sablings that the forresters already have taken down. I visit the forrest quite often, so they dont get to lie in the forrest floor for too long. I pick the straightest I can find about 3-4 inches i diameter, and its mostly ash, maple and birch. Then I cut them in half and let them sit in the garage for about half a year. I know longer is recommended, but Im impatient, and I dont mind that they set a little. The staves are about 60-70 inches long

I work on the stave with an axe and a drawknife, that I also use for scraping.I tiller slowly, and I do excersise the bows. When they tiller ok, I take the bow in for some extra drying, -and this is usually where the fun stops. I dont let them dry for more than a few days, and when they're back on the tiller I work slowly again, but suddenly they've become very brittle and the last two bows broke with very little stress (compared to what they could handle in the garage). I dont consider my house to be overly warm. -about 20 degree Celsius.

I'm not going for the extremes with the bows. Id be very happy if I could make a 20-30 pound bow.
I have dog bone rawhide ready for backing, but I've never reached the stage for applying on my latest 3 bows.

The pictures below are of my latest two bows. The top one is ash, I had great expectations for this one. It was almost done, though I hadn't drawn it to full lenght. Maybe only halfway. I could draw it quite far even after having it inside for 3 days. But last night when I thought I'd just excercise the bow a little i broke.

The bottom one, where the limb is missing is an hazel stave. Worked fine, almost had it to 80% of its draw lenght, but it then broke sitting still in the tiller.

I cant tell if the break started on the back or belly?

Did I violate the grain?

Is my design bad? (flat belly and sharp edges)

Should i apply rawhide as soon as the back is ready (before tillering)?

Any tricks to make a break-safe bow?


Please give your 5 cents on the pictures.. I need to know why my bows are breaking, before I'll get started on the next one.


Kind regards,
Søren from Denmark

[xin]

Soren, it appears to me that your crown may be too high, putting too much stress in the center of the bow, and it is possible your wood may be too dry.  When the edges are too thin and the back too highly crowned you are asking for trouble.    I made eight bows before I finally got one to the shooting stage and then I had to back it with rawhide to keep it from breaking.  My best advice is to try to find wood with less crown, which means finding a larger diameter sapling.  Don't give up.  Everyone goes through the frustration of having bows break before they are tillered.  Even after you become an experienced bowyer,  you will have bows break before they are finished, but they will become far less numerous.  If you stay the course and don't give up you will soon be making bows that shoot like you dreamed they would.  Stay with it.

[Pappy]

It don't have to lay out long to dry rot, cut some green healthy wood and season it yourself inside out of the weather and you will have better luck.  You can cut a green sapling,split it down the center,seal the ends and let it dry for a few weeks,the work it down to close to bow size and let it dry a little longer,remove the bark when you cut it and seal the back with something,Polly/wood glue just about anything will do. Then I bet you will get a shooter. 
 Pappy

[DarkSoul]

Good to have you here, Søren. Some of the best bowyers gather at Primitive Archer and I'm sure you'll find a lot of assistance.
You made a good and clear opening post with very precise pictures. This really helps us in figuring out what is going wrong with your bows. Myself, I think you are dealing with several issues, which all combined result in broken bows. So here's my two cents:
- I can't technically judge the tiller in any of the bows, since they are all broken and not drawn. But I think you have a real problem with tillering your bows. I can only base this on the ring pattern on the belly of the bows and on the width taper that I can see in the limbs. Your bows all appear pretty much the same thickness throughout the limbs and show very little width taper from the handle fade towards the tips. This will result in all bend of the bow located near the handle fades. And where do most of your bows break? In the handle fade! I therefore advice to spend more time on slowly tillering the bow and read more basic topics and YouTube videos on tillering. You should put more width taper in your bows and also some thickness taper in the limbs.
- In my opinion, these bows looks rather rough. I would not consider these ready for tillering. The width profile is not precise; it has valleys and waves in the sides of the bow. I can see a chunk ripped out of the belly in one bow. The corners/edges are still really sharp as well. None of the handle fades are smooth. All these spots create weaknesses. You want even lines, smooth surfaces and rounded corners before you stress the wood.
- The wood species combined with the high crown (round surface of the back) are less than ideal. Also, the flat belly will increase the stress on the round back. Instead, make the bow slightly rounded on the belly as well. This will relieve some stress from the highly crowned back (by putting this stress on the belly). You can also find a bigger sapling (say 4"-5" diameter), which will mean less crown. Your wood species are also not the greatest, but they should all work. Birch would be the least favorable, especially with this high crown. But maple and especially ash will really work in a sapling bow. Elm, if you can find it, would be even better.
- It's not the best thing to have this wood laying in the forest for some time. I don't know how often you go into the woods and looks for these saplings. But wood can really get damaged in maybe two weeks after it was cut down. If you take it home and put it in the garage, it may even deteriorate further since the fungus can still continue to grow and eat the wood. I would advice you to cut a (living) tree/sapling yourself, or to make sure it was cut down no more than one week ago. Wood should also not become 'weaker' if you dry it for a few days in the house. Your approach of drying in the garage first and then putting it in the house is very good. But give it a few weeks in the house before you stress the wood. Harvest the wood, rough it out today, put it in the garage for two or three months, and then put it in the house for two or three weeks. The wood should be totally dry by then, and only then you should start stressing the wood by tillering it.

With your next bow, show some pictures thoughout the process. From start to finish, so we can guide you through all the steps and have our assistance while you're working on it. I'm sure you can make a bow very soon!

Greetings,
Jorik

[TRACY]

Sounds like your stave source needs to change. Get fresh cut (same day) trees and debark and split. Then seal the ends and put them up to dry. Seems like this is a disadvantage to you. Best of luck!


Tracy

[Bogaman]

Soren-dk, You've gotten some good advise so far, especially from Darksoul. There are a number of issues for you to address. I would start with your wood, cut something green and continue from there like has been advised.
One thing no one has mentioned yet is your tools. You say you have an axe and a drawknife. This would be enough if you were an experienced bowyer. You at least need to add a scraper and file to your tool chest. A drawknife can do a lot of damage in  the hands of someone who hasn't used one much.
Keep us posted on your progress;^)

[adb]

Your work looks very rough... kinda like a beaver has been chewing on those staves! 

I would suggest optaining some finer tools, like a rasp and scraper. An axe and a drawknife are great for roughing out a bow, but they won't get you to the end.

[lukelawrence171]

yes i know what you mean i went through the same thing. im with adlb on this one it seems that your bows are to rough you might want to try even sanding the bow before tillering make it look like its almost ready to finish if you have even a little scratch in the wood it will usually break with that high of a crown.usually a scrape will do just make sure you get all the scratches out of the back of the bow.

[lostarrow]

 looks like a combination of poor wood, and rough work (as Adam stated) . Tool marks on the belly and the back will (almost always spell disaster) . With the species you are using you should only be taking off the bark and carefully scraping the cambium. It appears you have torn through several knots on the backs of your bows. They will bend fine while green  in that state ,but as soon as they dry (as you've experienced) they will explode. Backing won't save them from this mistake.
   The saplings you find as a by product of logging are rarely a good candidate for bows. They are often pushed over with the Skidder causing shakes (growth ring separation ) or have started to deteriorate (as Pappy said) If you can talk to the guys cutting and find out if you can take a sapling of your choice before they get to it, you would be better off. Often if you explain what you want to do with it, people are fascinated and more than willing to help. They may even cut and set aside a tree or two if you flag it for them . Better yet, you can request a straight section from the tops be left at 6'-7' and split it into staves. The tops are usually cut into firewood or chipped to make OSB (chip board)
   Remember, this is their work place and it can be dangerous. Approach while they are on break (preferably with coffee and donuts) if you can. If that is not possible , be aware of your surroundings and keep your distance  . Let them come to you to talk when they are done what they are doing. Let them know you want to talk but try not to distract them  from their task at hand. 

   Lastly, look through all of the info on here and ask lots of questions. It's just about the best resource you'll find. Traditional bowyers bibles are also well worth their investment. Consider how much time is consumed making bows that don't have a chance ,compared to $75 for 4 books. Where can you buy a hunting weight bow for $75? Let alone make a complete set  of arrows , string ,bow for less than $25 in materials and $50 in tools to start. With the price of the books on top ,that brings you up to $150  conservatively , for your first bow.
   The sky is the limit from there! Welcome to the addiction!
  Have fun and good luck with your future projects!
  Dave.

[NOMADIC PIRATE]

Your work looks very rough... kinda like a beaver has been chewing on those staves! 

I would suggest optaining some finer tools, like a rasp and scraper. An axe and a drawknife are great for roughing out a bow, but they won't get you to the end.

That's what I wanted to say but didn't want to ruffle any feathers    gotta put more effort in you craftmanship, primitive doesn't mean crude 

[son of massey]

Are you flattening the limbs on both sides? The second pic with the reconstructed bow looks like you have decrowned the stave off to the left. If you are flattening both back and belly you will break bows for sure without really knowing what you are doing.
SOM

[lebhuntfish]

Very well said, lostarrow! That was just about the same advice I was given! Patrick

[George Tsoukalas]

Soren,
Wood cut and left int he woods is not usable.
Here check mys site for help.
http://georgeandjoni.home.comcast.net/~georgeandjoni/index.html
Jawge

[Soren-dk]

Wow! Thanks for all the great replys. I must say that I'm a bit overwhelmed by the fast and thoroughly feedback. I've gotten plenty of good advice for my next project.

What I'll do now:

I'm not allowed to cut the trees in that forest, so I'll try to get to the people that do it, and figure out their work schedule. I'm sure it wont be a problem, especially with coffee and cake.

I actually didn't know that tool marks on the belly was a big problem, though I guess it does seem obvious that everything has to be silk smooth before tillering. I'm usually more careful on the back, though it seems I should be even more careful. I only remove the bark and scrape a bit with the drawknife.

I'll look for even wider trees, though I have read a few places that 3-4 inches should be ok. But I will back my bow with dog bone rawhide before tillering, cause it would seem natural, that the breaks start on the back due to the high crown.

I'll also make sure everything is rounded, and also aim for a more narrow and straight design. That way I shouldn't cut though the grain lines as much.

New questions arise..
I've acquired a rasp, a few files and a tool that I don't know the English word for.. A draw planer perhaps? Do I really need the scraper when I can scrape with the draw knife?

Is it better to go for straight lines on the sides than following the grain lines?


I'm especially glad to hear that many of you broke quite a few bows before getting a finished one. And I love the "If you aren't brakin' your aren't makin'" I'll keep that in mind.

Kind regards,
Soren

[bubby]

soren you don't have to buy a scraper, for the longest time I used a lockback knife with a six inch blade, or you can take a pair of scissors apart and use one for a scraper, you seem to have a great attitude and that will go far as sometimes criticism can be harsh, good luck and have some fun, bub