First bow - back selection - Broke

[bubby]

you need to do some scraping about a foot from the fades out on both limbs, bending a little to much inside, use a six inch straight edge to check it with, when it's bending evenly the gap between wood and straight edge will be constant, what is the bow braced to

[SeanStuart]

You got a really good eye. Thanks.

[bubby]

it's not looking to bad, just bending a bit much at the fades, I clean mine up, then do like I told you and start a foot or so out and i'll tiller back towards the fades later

[SeanStuart]

I scraped the limbs a bit more, and used the straight edge. I increased the draw a bit at a time and repeatedly drew the bow 20 or 30 times each increase. I took it out to a field and shot a few arrows just drawing about 3/4 of the way. On the 7th or 8th it cracked.

Maybe I didn't work it enough, or had too much wood out far on the limbs, so it was putting too much stress on the fades? Or maybe the wood had a weak spot there. If you see anything in the pics, please share. Thanks.

Hmm. Gonna need another chunk of wood!

[nakedfeet]

I wouldn't necessarily it was a problem with the wood. Looks like a "forced" run out from where the handle narrowed. No doubt that there is a run out, but had the bow been full width there it wouldn't have been a problem -- but that wasn't really doable. I had a board bow break there last fall. I wrapped it and the fix held, but later the bow broke somewhere else.

The wood was working too hard there. It's easy to see in the tillering picture. And next time make sure the edges around the back are rounded some more as well.

Consider these lessons learned.

[DarkSoul]

I'm gonna be straight up with you. You messed up the tiller and made classical beginner's mistakes with that handle. Bubby has been too kind by telling you that the bow was bending a bit too much in the handle. It was bending only in the handle. You were already bending in too far in that tiller pic. You should have drastically corrected that tiller before pulling it any more. Also, that glued on handle is too short and did not extend past the fade. Typical design flaw. This bow did not break because of bad wood. It was bending too much in the handle, and because the bow was getting narrower in the fade but not thicker, it broke right in the fade. If you'd been more patient and waited for more people to comment on the tiller, you could at least have corrected the tiller earlier on. Your handle still would have been too short, but that could have been compensated for by lowering the draw weight. Next time, reconsider the handle layout, spend a lot more time tillering, round the corners, do not shoot it pre maturely and select your wood more carefully.

[SeanStuart]

Thanks ezc. I see your points, and I was looking at that point when I cut the board away from above and below the handle.

Lotta good stuff here DarkSoul.
I'm gonna be straight up with you. You messed up the tiller and made classical beginner's mistakes with that handle. Bubby has been too kind by telling you that the bow was bending a bit too much in the handle. It was bending only in the handle.

Is there a rule of thumb, or estimate of how much the thickness of the limb should decrease from handle to nock, or is every board different? For example 25% decrease or something similar, or what have you found to work in the past?

You were already bending in too far in that tiller pic. You should have drastically corrected that tiller before pulling it any more.

First bow so I wasn't really sure what to look for other than a smooth bend with no flat spots or hinges. It is also difficult to pull it down and then step back to look at it without seeing it actually bend. I guess next time I'll get someone to pull it down so I can watch.

Also, that glued on handle is too short and did not extend past the fade. Typical design flaw.

I do not think the handle was too short when I glued it on, I just cut too much off. Same thing  I guess.

This bow did not break because of bad wood. It was bending too much in the handle, and because the bow was getting narrower in the fade but not thicker, it broke right in the fade. If you'd been more patient and waited for more people to comment on the tiller, you could at least have corrected the tiller earlier on. Your handle still would have been too short, but that could have been compensated for by lowering the draw weight.

Next time, reconsider the handle layout, spend a lot more time tillering, round the corners, do not shoot it pre maturely and select your wood more carefully.


I thought the back was supposed to remain mostly flat. What does rounding the corners do?

This bow did not break because of bad wood.... select your wood more carefully. Seems like you need to choose one. What don't you like about the wood?

Thanks for your observations.

[WillS]

I think the problem was in shooting it to be honest.  As DarkSoul has already pointed out, the tiller needed a lot of work, but that's normal at this stage.  Easily corrected.  However, shooting it put a whole load of stress and shock through an unfinished bow so any potential weak spots were made to do a whole lot of work.  With the tiller the way it was, there would have been a fair wallop of hand shock, so making the bow actually shoot at that point was a really bad move!

Impatience is a killer - we've all been there! Try not to get excited and go shooting a bow before it's actually working the way it should be.  Other than that... Keep on keeping on.  Next one!

[Badger]

  You do sem like a nice enough gentleman but I have to say that with the attitude you approached this bow and those that offered advice yu really did deserve a broken bow. Better luck on the next ones and the same guys will be here to help you with that one.

[nakedfeet]

Come on guys, I don't think he did anything to warrant harsh treatment.

Thanks ezc. I see your points, and I was looking at that point when I cut the board away from above and below the handle.

Just remember, any time you're reducing width, you are violating wood fibers. It can't be avoided -- but the effect of it can be minimized.

The first bow I broke outright was an early attempt at a Mollegabet-type bow from a maple board. Everything was going (relatively) fine, and then it broke when I was flexing it on the ground.

To my eyes, the board looked OK -- straight grain and growth rings that didn't wander off the sides. But as far as I can tell, the crack started at the "shoulder" and took off from there. From the break, it's obvious that the grain wasn't as straight as I thought.

(Luckily, it seems oak boards are easier to read than maple.)

On the bow that I'm finishing up now, which I will probably make a post for in a couple days, I have a spot that worries me a little in the same place you had your crack.

A few bows later I had a break like you have here. Another maple board. Same deal: board looked good, but the break started right at the end/beginning of a width taper.

My problem was not that bow bent too much in the handle -- in fact, it was somewhat whip-tillered. Instead, I believe the "cause" (or, at least a big contributing factor) of that crack was that the glued-on handle was too short -- something others in this thread have pointed too as well.

This is something I'm still kind of trying to figure out. I was really bad at gracefully reducing the thickness into the board proper for several bows. But I think I've found what works. On my last bow I had three pieces of 1/4" oak glued together, the longest one 7" long. This is for a pretty standard 4 inch handle and 2 inch fades. So 7 inches of glued-on wood for an 8 inch middle section. On the first inch or so of "board" wood the thickness continues to reduce pretty considrably.

On this bow, which I'm finishing up (and will probably post about in a couple days), I also have a "forced run out" that I'll keep my eye on -- but my worries are minimal. The fade is graceful without any sharp transitions, the corners are rounded nicely, and I think the design was well picked and executed. We will see how it holds up to use -- but I'm not really worried about it.

(Rounding the corners is just a way of reducing stress. If there is a wood fiber violation at a sharp corner, the tension stresses will be very concentrated there and it will more easily tear away. But if the stress is kind of spread over a slightly larger area, the wood can handle it better.)

In the end, bow making is hard. There are so many variables. Even though board bows are "easier," they're still hard -- and they come with their own unique challenges. Don't take this break too harshly. Consider them lessons learned.

Is there a rule of thumb, or estimate of how much the thickness of the limb should decrease from handle to nock, or is every board different? For example 25% decrease or something similar, or what have you found to work in the past?

I can't answer this really -- it will vary based on your design, and of course the particular piece of wood, but what I can offer you is that a bow needs to either reduce in thickness or in width all the way down a bows limb. That's my "rule of thumb." There are exceptions of course. But if it's the same width and same thickness most of the way down, it's going to bend far too much in the middle.

First bow so I wasn't really sure what to look for other than a smooth bend with no flat spots or hinges. It is also difficult to pull it down and then step back to look at it without seeing it actually bend. I guess next time I'll get someone to pull it down so I can watch.

This was an issue for me for the first few bows. I didn't understand what a proper tiller shape was -- just knew that it should bend "even." I don't have a link on hand to show different tiller shapes, but someone might. I was going to post two examples of my own but got self-conscious all of a sudden. :X

Look at all of the bows people post here. Analyze them on your own. Read what more experience bowyers have to say. Eventually it will make sense.

[bubby]

first off I don't think the handle is to short, I think the fades might be to short, and don't take darksoul the wrong way, he's giving good advice, he's just not very diplomatic about it and gets right to the hart of the matter, rounding the edges helps with slivers lifting, take the advice offered, get another board and get back to work, pay attention to the grain on all 4 sides

[Crogacht]

Irrelevant drivel was here 

[bubby]

crogacht this is a stiff handled bow

[GB]

" It is also difficult to pull it down and then step back to look at it without seeing it actually bend."


New guy here and still pretty new to bow making (2 years, 12 bows), but I can help with that problem.  Bolt a pulley towards the base of your tillering tree and run some strong rope thru it with a clip on it to attach to your tillering string.  You'll have to take your nails out and drill holes instead at your inch marks.  I use a bolt as a peg.  Give it a try; bet you'll really like checking tiller that way.  Good luck on your next one.

[Crogacht]

crogacht this is a stiff handled bow

So it is. That's a bit less confusing