Primitive Archer
Main Discussion Area => English Warbow => Topic started by: WillS on May 22, 2013, 05:53:24 pm
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I'm about to start tillering a new ash warbow I'm working on, but the stave has about 2 - 3 inches of natural reflex in the lower limb.
I'm shooting for 100# @ 32", as the ash is incredible quality. I've made it as wide as possible and a very shallow D profile to counter the possibility of set and chrysals that ash seems so prone to.
The trouble I'm finding is that with the roughed out bow being so large already (40mm wide in the handle by 32mm thick) and with so much reflex, the early draw weight is immense, which is making gauging the tiller pretty tricky.
Is there a technique or method for tillering heavy bows with uneven reflex? I'm tempted to start reducing the thickness on the reflexed limb to bring it round equally to the upper limb, but I'm sure that will backfire during the later stages of tillering and leave with me a lighter than desired bow.
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Best advice I'd give is to get a really good bend while floor tillering and get the limbs as even strength as you can judge so you can get it braced early. Using a long string to tiller a bow with reflex usually causes it to flip over so getting it to any brace would prevent that. Draw weight won't change very much between a low and high brace so just focus on good tiller.
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Thanks! Does floor tillering work for heavy bows? When I try, nothing moves haha!
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Yep! Gotta put your weight into it. It helps to use a mirror set up against a wall and on the floor so you can look at it directly through the reflection while putting your body into it. If you have a warbow that's finished push that against the floor to see how it feels.
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Its a pig if the limbs are V uneven.
IMO DON'T 'weaken' one limb to bring it round else you'll find the draw weight has dropped too much on that limb.
Reflexed staves are V tricky too as they will try and flip on you until you get somewhere near brace (pig to string with a short string too).
It is also easy to take off too much weight on a long string just getting back to brace.
A couple of thought/ideas.
Get the bow on the tiller with the tips lining up horzontal rather than the grip. Is it possible to draw a straight pencil line along the side of the bow and use that to look at rather the limb?
Maybe it's one time where clamping the bow to the rig may help observe the individual limbs and stop it flipping in the early stages?
When in doubt step away and have a cuppa. V long bows and bows with reflex can seem V high poundage and then melt away before your eyes to a feeble bow... Ok a slight exag' but you get the drift.
Del
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Cheers Del. I actually tiller upside down, with the string anchored at the top, and the tillering rope pulling the handle down. It seems to make life easier (on straight staves..!)
I'll have a crack at tilting it, so the tips are lined up regardless of the handle and see if makes visualising it a bit easier.
S'awkward though, with it being ash. I'm used to having proper D-section profiles for longbows, which doesn't work with ash. It makes removing small amounts of belly wood but keeping an even keel and rounded edges quite tricky. I can see myself taking too much off very easily.
This is going to require a LOT of tea.
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I've found tillering heavy war bows with reflex to be very challenging. Tillering a stave with reflex in one limb would be even more tricky. I think you might have trouble with the reflexed limb wanting to roll over at low brace. Getting it to full brace and making weight will be tricky! Once you get it bending, it'll be better, but getting it there is going to be a challenge. Watch you don't get the stave banding too much in the middle too early. Can you heat correct both limbs first, so they're more even? That's what I'd do. Good luck!
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Thanks Adam. It's definitely trying to flip on me! I had to abandon tillering for a bit as it just wasn't behaving. I went back to floor tillering it and really leaning into the thing but it's a bit of a monster.
My worry at the moment is that the last 8 inches or so are thin enough to bend quite comfortably, while the rest of the stave is far chunkier AND reflexed, so I'm in real danger of inducing far too much strain on the tips before the rest of the bow starts to move the way it should. This has taught me to keep the last third pretty heavy on a stave like this.
I'm toying with the idea of heat treating, as it will certainly help overall. I had wanted to finish this bow without using any heat though, as all my other bows had to be subjected to so much dry heat and steaming that it would have been really nice to avoid all that. Of course, if we all got what we wanted when making bows it would be pretty boring...
I'll keep you guys up to date with this, and hopefully have some pics to show what I'm working with at some point. Thanks for all the pointers already!
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Steam is (IMO) a lot gentler on the wood than dry heat. May be worth investing in a cheapo wallpaper steamer and finding some offcuts of insulation board etc.
Gotta admit that getting the two limbs to match will make it much easier to tiller.
Keeps some width on those tip too to allow for any string line adjustment.
I tend to tille rfrom the middle out... but that's just the slightest flexing near the middle whilst exercising it at full draw weight and watching it up close (not easy on a big warbow)
Good luck!
Del
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Right, got some pics for anybody who's up for offering some tips! I've put it on the tiller upside down (to me!) because I think most of you tiller this way, so hopefully that's easier to visualise for you.
First pic is the bow under no tension and second is under about 50lbs, or just enough to get the tips moving.
My worry at the moment is that deflex area on the right limb. To my inexperienced eyes, that screams "hinge" but as it's deflexed without any tension, do I still treat it as a hinge?
Basically, where would you guys go from here? This is kicking my ass at the moment, as I'm aiming higher than I have before, and the stave is a tricky one as well. Heat treating isn't out of the question yet, so if that's the best advice then of course I'll do that. But I'd rather not!
(http://i1202.photobucket.com/albums/bb363/Will_Sherman/WP_000620_zpsbd3fe518.jpg) (http://s1202.photobucket.com/user/Will_Sherman/media/WP_000620_zpsbd3fe518.jpg.html)
(http://i1202.photobucket.com/albums/bb363/Will_Sherman/WP_000622_zpsad7c47ea.jpg) (http://s1202.photobucket.com/user/Will_Sherman/media/WP_000622_zpsad7c47ea.jpg.html)
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Where would I go from here?
Pile on the draw weight!
The bend in the right limb is just what was there initially.
Look at it this way... If you intend to pull it to 100# you will do less harm pulling it to 100# now, where the deflection will be less and the potential for a hinge less. Than if you remove wood, making it thinner and weaker and then expecting it to withstand 100# !
I'm not saying yank it right back to 100# without watching it, but winch it 60# 70# 80# etc keeping an eye on it.
It's just gotta be done, also bear in mind 100# on the long string at a tip deltlection of say 3 or 4" isn't going to overstrain it, as 100# on a long string is about 75-80# braced.
I'd aim to see some slight movement near the middle and a reasonably symetrical tip movement at a long string 100#
If you can get that, then you can breathe a sigh of relief knowing it's taken 100# and you are well on the way to just slowly teasing it back.
Better to see what it will do know than pussy foot around too much and risk coming in under weight.
Other opinions are doubtless also available.
Del
(BTW When piling on the weight, check there is no one standing behind you with a paper bag!)
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Most of the reflex appears to be in the middle. I usually get the middle moving first anyway. As Del suggests, give it a tug to 70 or 80#, and see what it looks like. Dealing with this is no different... remove wood where it's not bending enough, and leave it alone where it's bending too much. That being said, you're going to want to leave the right tip alone. Try and get rid of the long string asap, and get it to low brace. Those reflexed/deflexed limbs will fool you with too much time on the long string.
This is going to be tricky, but get the middle moving first.
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If you realy feel you must remove weight take a tad off the left.
If you really study it, the right limb hasn't actuallt moved but the left has pulled down by about the same amount as it's thikness. Now this is probably due to the left being stiff and pulling down see saw satyle nad flexing the right.
Bottom line.. there isn't enough deflection to really see what's happening so pile on the weight!
Del
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Eeep. So there's no risk of causing set in that right outer third? Everything's telling me that the first thing I should do is remove wood on the right inner third to relieve the outer, before continuing.
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Get the two pics on the desktop and flip between one and t'other to see where the band really is.
I don't think it's right outer limb.
I've just done it, and I reckon it looks like the bend is actually in the middle to inner of each limb.
Look here, I've turned it into a video.
http://s411.photobucket.com/user/Del_the_Cat/media/websitevideos/tiller_zps735507b3.mp4.html (http://s411.photobucket.com/user/Del_the_Cat/media/websitevideos/tiller_zps735507b3.mp4.html)
Wierd thing is the right tip is LESS deflexed under load!!!
You can see the value of having a fixed camera position. It would prob be more obvious with less dwell on each pic and a solid camera pos'
Tell us what you see!
Del
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That's very cool, thanks for doing that mate! I'll put some back into it then, and start heaving it down some more. It's not trying to flip on me too much which is nice at this stage, so hopefully I'll be able to brace it without giving myself a hernia.
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Nice work Del! I'd still get it bending in the middle more and worry about the tips later. I wouldn't call your right tip a hinge yet, but certainly keep your eye on it.
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My worry at the moment is that deflex area on the right limb. To my inexperienced eyes, that screams "hinge" but as it's deflexed without any tension, do I still treat it as a hinge?
It very easily could become a hinge. Any deflex in a stave, in a part that is going to be working limb I mean, can easily become a hinge if you are not careful. This is assuming you are going to just tiller out the stave with the deflex in it, without steaming or heating it out. You want to be very careful when tillering. If you have to remove wood from that spot, do it little by little. What I would do right now is (other than pulling the stave just a tiny bit more to have a better look at whats going on) is definitely work on the reflexed left limb. And of course a bit on the right limb, right off the handle, but mostly weaken the reflexed left limb till it matches the right. When everything looks even and matches, with an even bend, then go from there like usual. When the bow is tillered completely, doing it this way (tillering it out to where the bend looks good to the eye, despite deflexs or reflexs in the stave), the limb that started out deflexed will be a good amount stronger than the left limb. This is because it will not have to move as far as the reflexed left limb to reach the same place, so it has to be stronger to be even with the left. And especially the exact deflexed spot, that spot will be thicker than the rest of the bow, which it has to be, to prevent it from hinging. Although to the unsuspecting eye, you will be the only one who knows all this, ;D. And obviously the deflexed limb will end up being the bottom one, as the bottom limb should always be the stronger limb.
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Thanks for that reply dude, very helpful!
Really interesting regarding your last point - I was working under the assumption that the left limb (reflexed) would be the lower limb, as currently it's a lot stronger. My offset handle is arranged in this way, as in TBB it's said that you pick the limb naturally facing the archer to be the upper limb. But like you said, once everything's finished and the tiller is even, at that point the deflexed limb should be stronger. Which throws everything upside down!
This bow making thing is crazy.
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There's certainly more to it than most people think!
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Thanks for that reply dude, very helpful!
Really interesting regarding your last point - I was working under the assumption that the left limb (reflexed) would be the lower limb, as currently it's a lot stronger. My offset handle is arranged in this way, as in TBB it's said that you pick the limb naturally facing the archer to be the upper limb. But like you said, once everything's finished and the tiller is even, at that point the deflexed limb should be stronger. Which throws everything upside down!
This bow making thing is crazy.
I know John Strunk said that I believe in one chapter, but it (respectively of course) just ain't what I have found to be true. I have always wondered about this, if he made a typo or something? Because the reflexed limb will always have to be made to be weaker to meet the deflexed limb, and the deflexed limb will always have to be left stronger in order to move less than the reflexed limb, ya know what I mean? Maybe he tillers his bows overly asymmetrical, where the bottom limb is very very stiff or something, I don't know. I tiller my longbows symmetrically for the most part, with just a slightly stiffer bottom limb, not enough to make it worth measuring a difference in brace height, just a smudge stiffer. Maybe between a 16th and a 8th an inch difference at the most I think. But when tillering a stave like this, no matter if the bottom limb "appears" to the eye to be alot weaker (when using the stronger deflexed limb for the bottom), it can still be a good deal stronger.
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This pic is more for my benefit than to ask you guys for help again, but obviously if you spot anything glaringly obvious feel free to mention it!
This is pulling 80# at about 18" on the long string. The deflexed area looks much better now, and I think my focus needs to be the inner third to middle of the left limb to even things up. I want to get this to brace as soon as possible, to avoid staying on the long string too long as you all mentioned. I don't think I'm far off.
(http://i1202.photobucket.com/albums/bb363/Will_Sherman/WP_000626_zpsdf835eb5.jpg) (http://s1202.photobucket.com/user/Will_Sherman/media/WP_000626_zpsdf835eb5.jpg.html)
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The left limbs bend is looking good. The right limb looks like it is working mostly in the middle of the limb, and not enough towards the tip and right off the handle/center. I would take a bit off the tip of the right limb, and a bit off the area right off the handle/center (if you know what I mean, off the "fade" I guess, even though these bows don't have fades, like where the fade would be) of the bow on the right limb, trying to get it working evenly and not too much in the middle. Or anywhere else for that matter, :). Also, I would remove material from the entire left limb at the same time I do that, to weaken it a smudge at the same time I am weakening the right limb. Course, it is kinda hard to tell what exactly to do from here, just cause it isn't bending that much, that is just probably what I would do. It is looking good though!, 8). Can you shorten your long string any? Is it stretchy? It is better to have as short a longstring as possible, if you can. I know nylon cord will a lot of the time stretch no matter what though.
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I definitely agree about the whole left limb needing to work a bit more, so I'll take the whole limb down a fraction. I'm wary about playing with the middle too much yet, as it's not even brace height yet, and I don't want the middle working too early if that makes sense?
The tillering string is just an extra long bowstring, from about a million strands of B50. I'll shorten it up once I've got the left limb a bit weaker and see where I am!
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Couple of weird things are happening. I shortened the long string to the point where it was very tight against the belly and suddenly the bow started curving laterally. It's now got a permanent C-curve throughout it's length and the string has stopped tracking straight. It's also suddenly taken a lot of set in the reflexed limb tip (the left limb in the pics)
And it went "POP" on the tiller. All in all, a successful bit of work. :o
Grrr.
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Pop? Did it break? Lift a splinter?
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Just a loud pop. I've gone over it in the best light I can find and can't see a single thing that would worry me. No splinters, no cracks nothing. But a noise that like on a bow this heavy is enough to make me wince when I'm stringing it.
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Did the string pop out of the nock?
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I guess that's possible, yeah. I'll be taking it slow from here, if I decide to carry on.
This lateral curve is a pain in the ass. I have no idea how it's even possible for a bow to do this. The stave was dead straight with no propeller twist or curvature whatsoever, and now it's so bad that the string falls off the side of the handle. I can see how propeller twist might develop as a bow is tillered, but sideways bend?! Doesn't make sense!
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I've had the same issue with trying to tiller heavy bows with reflex.
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Shift the string across at the nocks , maybe clamp the grip or put a thin wedge under it. You've got to for ce it to do what you want.
Lots of small corrections can make all the difference and once it's back to about brace it will be easier to hold it in line.
Leave the tips full width and stick a scrap of wood on the back at eah tip to cut a groove in for a nock. This maximises your lateral string adjustment.
Persevere now and it will be ok later on.
Del
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The tips are 20mm wide and even with the string loops on opposite edges of the tips the centre still falls off the side of the handle. It gets worse at brace as well. I wouldn't mind so much but it's now so offset that it's flipping constantly on the tiller.
I might have to do what you said and clamp it flat on the tiller, but that will require building a new tiller setup as I can't do that on my current one. Laminate bows are looking so tempting right now >:D
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I definitely agree about the whole left limb needing to work a bit more, so I'll take the whole limb down a fraction. I'm wary about playing with the middle too much yet, as it's not even brace height yet, and I don't want the middle working too early if that makes sense?
The tillering string is just an extra long bowstring, from about a million strands of B50. I'll shorten it up once I've got the left limb a bit weaker and see where I am!
Good point about the middle, you always want to get that really bending last. Or at least I do. I kinda meant the "fade", but you have a good point too. I usually tiller the bow from the tips outward kinda, but mostly just look for areas that are bending too much or too little. B50 is stretchy, and imo sucks as a bowstring and definitely a tillering string, when the weight is higher. What works great is some 550 paracord, as there is like no stretch and you can just tie it in a normal knot without worrying about it breaking. I by mine at lowes for 8 bucks for about 50 feet or so. Fast flight would make a better tiller string as well. And I am thinking like abd, the pop was probably just the string popping out (did the string come off at the same time of the pop?). Well it may of just popped out a little bit and make a sound without coming fully out, I have had it made noises before. I think the best thing to do in this situation, if you can't clamp it down, is to get a mirror and lay it horizontally on the floor, and tiller the bow by stepping on the string and pulling up while looking at the mirror. You have to be careful not to hurt your back while tillering heavy bows like this, but other than that, I think it works great as you can hold the bow firmly in your hands and keep it from flipping over. When you get it up to a 6" brace (if you floor tiller it far enough and good enough you can go right from floor tillering to a 6" brace, but it takes a bit of practice and sometimes you might whip the tips if you don't get the full limb bending.)
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The tips are 20mm wide and even with the string loops on opposite edges of the tips the centre still falls off the side of the handle....
That doesn't make sense to me...
If it's flipping one way, then the string needs pushing to the other side at both tips.
E.G. Facing the bow, with it's back uppermost, pulling down on the string (say there's a wall bahind the bow). If the tips are coming towards you instead of straight down. Then the string needs to be pusshed to the back edge of the nock on both tips, towards the wall. This will move the string line to the wall side of centre encouraging the tips to move towards the wall rather than towards you.
If you've moved the loops to opposite edges, then the string line at the middle of the bow it's the same as if the loops were both dead centre as the string is running diagonally across (like a bow with side nocks).
(or maybe there's just a breakdown of communication here...)
Del
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I think I must have missed something fundamental when learning how to make a bow.
This extra wide piece of seasoned ash, which started with 3 inches of reflex now has 3 inches of string follow, which equates to it having taken 6 inches of set. It's not been pulled anywhere near the intended draw-weight, and has only come back to about 18 inches so far.
To make matters more annoying, the lateral bend gets worse each time the bow is braced (although I've never even got it to a brace of more than 2 inches yet) and is now pretty much unworkable as even with the string loops as far across as possible on both sides the string is still nowhere near the handle anymore. It doesn't make any sense to me! I've gone slowly, and left plenty of room for mistakes. The tillering was slow and gentle and like I said, I never went beyond the intended draw weight. I haven't even reached it yet!
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A few thinks to look at.
1. Did you taper the width from the handle section? If so it can affect stability. Better to start these tapers a bit further down the limb or go for 2 tapers. With the nocks 20mm wide it doesn't sound like the limbs are too narrow.
2. It sounds like your ash is too damp. Keep it inside between the times you are working on it. Some bowyers don't even let ash bows rehydrate after heat treatment.
3. Was your bow too rounded in the belly as well?
4. You may be able to rescue matters by heating the bow and bending against the direction of the cast.
Jeremy
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Hi Jeremy!
1. I did sort of follow the MR bow tapers, in that the centre 20 inches or so is pretty much parallel, tapering once towards the tips, and the goal was to taper again the last few inches to the 15mm nocks once the bow was 90% tillered
2. The ash is a good few years old, and always kept inside. Not near heat especially, but somewhere warm and dry. I would love to blame it on the wood instead of my poor skills, but I think in this case it's all me!
3. The bow was almost square, instead of the traditional D section. I know that ash is tension strong, so the belly needs to be far flatter than a traditional yew longbow in order to avoid set
4. I'm gonna have to heat this, but I was really hoping not to! On the Warbow Wales website is a record breaking ash warbow with very similar dimensions to mine that hasn't been heat treated or reflexed at all. I end up having to heat treat every bow I make to rescue or avoid string follow and each time I start a new one I aim to avoid needing to do it.
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This is the bow I was following as inspiration
http://warbowwales.com/#/welsh-ash-record-bow/4562210258
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Did you notice at the bottom of the description? No reflex or heat treatment.
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Yep, that's why I don't want to resort to using heat. It's clearly possible to make a heavy ash warbow without it! I assume they mean there was no added reflex.
I wonder if I'm trying to run before I can walk. I've only made a few bows. Would you say a heavy bow is harder to make than lighter bows? Perhaps I should stick to bows around 50# until I've got the basics down?
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Yes, I would definitely say making heavy weight bows is harder. Is for me, anyway.
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Yes, I would definitely say making heavy weight bows is harder. Is for me, anyway.
Shoot, for me it's the opposite. For me tillering lighter shorter bows takes more skill than warbows, just because removing less wood makes for more of a difference in tiller. And I think it is easier to get chrysals or a bow breaking hinge in a shorter bow. I only get chrysals in warbows if I use a weak wood, for the most part the bows are so long is it hard to really stress em too much, despite the high weight. This is how I feel anyhow. Now it sure is physically a lot harder for me,... I need the exercise though! ;D
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This is the bow I was following as inspiration
http://warbowwales.com/#/welsh-ash-record-bow/4562210258
And that fellow sure is drawing that bow funky like. He is drawing it unevenly, mostly the bottom limb, you can see it in the arrow and the bottom limb bending more.
Edit: And with a hemp string too, cool! Don't see alot of those, must be good hemp not the stuff around here.
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I think I fell straight into the trap Del was talking about, by making the reflexed limb weaker to match the other. It certainly wasn't deliberate, and I was trying my hardest not to do it, but when looking at it on the tiller I just couldn't trick my eyes into leaving that limb alone before it was really working. If I'm lucky, and with a LOT of heat treating, this bow that was designed to be 100# will finish at about 45# which is diabolical. It will also be massively overbuilt for that draw weight, and having been pulled to around 80# during tillering is of course hugely over stressed.
I always try and take away lessons from each failure to avoid it happening the next time, but apart from the above, I really don't know what went wrong here. I'm still in the dark as to why it suddenly started bending sideways, and really surprised at how much weaker the limb that originally was reflexed the most now is.
I like to think part of it is down to using an adapted Mary Rose design on a bow wood not suitable. I know that ash works well with some heat treating, and especially well with a trapped back. But that bow on the Warbow Wales site has completely thrown me, because it breaks all of those rules and still comes out at an unbelievable draw weight.
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Another factor to think about is density. Ash can range from .6 to .8+ SG and it makes a large difference to the draw weight for the dimensions. There's loads of ash about (at present:-/) so have another go and make some shavings!
Why not give this bow away to a young archer and build on what you have taken from this bow in mark II, and after all, it was a bow and not a load of splinters!
Good luck.
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Aye, it'll be perfect for the girlfriend! The great thing about this hobby is that nothing is ever wasted. The worst that can happen is a bow explodes, which should teach you something you can use next time, or you end up with a perfect gift for somebody!
Thanks for the words of support, on to the next one!