Need help on my first T/D/R

[Jon LOW]

I am in the process of trying to make my first Take down Recurve (and first bow). I just strung it up for the first time tonight and gave it a test pull, got it to about 1/2 draw and one of the limbs snapped... I cannot seem to guess why it snapped where it did and how to have this not happen in the future. If anyone can give me some advice that would be very appreciated.

The Riser is Maple, Mahogany, Veneer layers of Maple/Cherry/Maple, then Wenge in the center
The Limbs are Maple on the front, with Hickory in the center, Walnut Risers (8"), and Bamboo on the back.
I used and slightly modified the plans from this post:
  http://tradgang.com/noncgi/ultimatebb.php?ubb=get_topic;f=125;t=009125  

here are the before and after pics:
  [/url] [/IMG]    [/url] [/IMG]  [/url] [/IMG]  [/url] [/IMG]  
Thanks again for any help or advice!

[LittleBen]

In general, building a takedown recurve out of all wood is a challenge I would only suggest to a very experienced bowyer. The biggest challenge is that a takedown riser, and the limb wedges (what you called 'risers' I believe) are relatively long, so there's not a lot of limb that actually bends. This makes it critical that your materials are very high quality, properly chosen, and your tillering is perfect. It will also typically require a relatively short riser, and a relatively long bow.

In general, for a well tillered tri-lam bow, I would be looking for the bending portion of each limb to be the same length as the intended draw length. So if you want a 28" draw, each limb needs to be 28", or at bare minimum 90% of draw length, so say 26". That's 52" right there ... add a 6" limb wedge in each limb, and a riser(handle) that's gotta be probably another 8" between the butt end of the limbs, and you're talking 72" total bow length.

You can see how this gets out of hand pretty quickly. Can it be done? Sure. I've made several, and seen several other bowlers make them, but again, these are better left as novelties for the most experienced and self directed bowyers IMO.

If I had to take a blind guess why it failed I would say that the edges of the limb were not well rounded and a splinter lifted up on the backing (the maple) and it exploded. It was also probably too short of a limb, and/or not tillered to bend evenly.

My advice is put the takedown on the back burner, and consider a 1-piece bow for right now. There are lots of great bowyers on here that will help you through from start to finish.

Maple (if it's hard maple) makes a great backing, almost anything is a good core, and bamboo (I assume you used flooring) can be used for the belly, although there are better options. So if you've got more material left over, I'd suggest thinking about a nice 1 piece longbow.

As a final note ... I've rarely taken apart my takedowns ... and even though I was meticulous in building my latest, it's breaking down after maybe 400 shots, whereas I have many other 1 piece bows that show minimal signs of wear after that long.

If you want more insight into why the limb failed, post some pictures of the break from the back, the side with the maple.

Hope that helps. Cheers.

[die_dunkelheit]

I agree with what Ben said, all wood take downs are very difficult and I too have almost never actually taken mine apart. Take the work you've done on this one as a lesson and move on to another.

[Jon LOW]

Hello, Well thanks for your quick reply and good advice.

First, I like a good challenge... and to me it sounds like if I can make a good all wood Take down Recurve, then I can make almost any other kind of bow... challenge accepted...

Second, just so you know the dimensions of mine:
Riser (handle): 19"
Butt of limb to butt: 12 1/2"
Limb Butt Width: 2"
Limbs: 26"
Limb Wedges: 8"
string Nock to Nock: 6
Aside from that all the dimensions are roughly identical to the plan in the other post I mentioned.

Just so I can see the proportions that you are referring to, could you post/link a pic of one of yours?

I think my problem is the maple that I am using, it is just old maple base trim that I planed down... I will use something else next time...
The Bamboo I used was from scraps of Bamboo sheeting (1/2"x4'x8') that a friend had

The main reason I wanted to make a TD is so that if a limb broke, then I wouldn't have to rebuild the whole thing... The other reason Is that I can get lots of free wood in shorter chunks, not a lot of free 5-6' lengths come my way... If I can make this one successful then I will move to other styles.

here are more pics:
[/url] [/url] [IMG]

[KenH]

When you say you strung it for the first time, do you mean that you did not tiller the assembly on a tillering tree, starting with a long string working into a regular string, then continuing to shape on the tree until you got to full draw??

That's the way most wood bows are done.

It sounds as if you just waited for the glue to dry, sanded a bit, strung it up and pulled it back.  That's a surefire recipe for failure!

[Jon LOW]

Well when you say it like that then it sounds pretty stupid, and that is what I did... Lesson learned

Does anything else in what I did sound/look wrong?

[mikkekeswick]

Have nobody spotted that the maple back is spalted.....
You can't use rotten wood for the back and expect it to become a bow!
Use only the most perfectly straight grained wood to back any bow with.
that boo you have is really only any good as a core.
So get some quality wood and I'm sure you will have better luck.

[stickmonkey]

Build it as you would a tri-lam. The same rules will apply as for proper backings and tillering.

The shorter the limbs get the more you need to increase the limb pad angles. Reread little Bens post above as its real good.

With glass bows we will use 19 -21" risers because the glass can be stressed more in short limb design. Making your riser 15" would also go a long way in helping you build a wood composite take down recurve. It will be more forgiving and provide you with more working limb.

[LittleBen]

Mike, I thought it was splayed at first too, but I think it's just the image makes it look darker. Either way, the grain is obviously not great as you can see from the tip end of the break.

Jon, I admire your determination and I will try to help you either way, as I'm sure others will as well, but I would renew my suggestion for a one piece. I understand the desire and benefits to a takedown, but I can assure you that by making a takedown, you are committing to building many limbs, whereas a one piece is much less likely to fail for the reasons I discussed in my first post.

Furthermore, I would suggest that you learn to walk before you run. Wood bow building comes down to one critical skill; tillering. Tillering is the process of carefully removing wood to ensure the entire limb bends evenly and smoothly along its length so that no one part gets too much stress.

I would recommend you read some of the many board bow build alongs which have been posted, read about tillering, learn the terminology, and ask questions about anything unclear. Lastly, I would recommend that you consider building a board bow first because the truth is, until you learn proper tillering, you're not likely to build a bow that lasts for much time at all.

If you must see, Here is a link to a build-along I did for a takedown. Keep in mind, that wasn't my first bow ... more like my 21st bow. Also keep in mind that my draw length is maybe 25", so obviously my bow will have shorter limbs than a longer draw would require.
 http://tradgang.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=125;t=010908;p=1

As to your dimensions, if your limbs are 26", and they have 8" wedges, then they only have 18" of bending limb. That's at least 8" too short for a 28" draw. If you've got 12" between the limb butts, and 8" wedges, that's 28" of stiff section, then 26"-28" more for each limb and you're talking about 80-84" bow in order to get the limb length you need.

For the takedown I posted, the riser was 14" and each wedge extended 2.5"  past the riser for a total of 19" of stiff section. Then 22.5" of bending limb in each limb for a total of 64". That bow also is a longbow and so bends almost all the way to the tips.

[KenH]

If you build a good board bow, you can then make it a takedown using the socket system.

[Wolftrail]

I agree with the others. I have built a few all wood take downs, and try to keep the working limb at least 25".  and I cannot stress enough to taper the lams in a big way.  I have one TD that has a 16" riser and 67" NTN.  It has over 800 shots and it keeps shooting like a trooper. It took only 1/4" of set. I spent over 4 days tillering it.

[mikkekeswick]

If that ain't spalted i'm a monkeys uncle....  One limb is clear, one isn't.
Working limb as long as your drawlength. 12 - 15 inch riser.
Above all perfectly straight grained wood is essential.
It won't break if you get the materials correct and stick within proven design parameters.