Primitive Archer
Main Discussion Area => Bows => Topic started by: Dictionary on September 05, 2016, 01:24:49 pm
-
Since getting relocated to eastern NM, I've been using red oak exclusively(nothing else here) to get back into bow making. I can't get this stuff to bend without taking way too much set. Is it the Red Oak or is it me?
I've been tillering by either using only a mirror or using a tillering stick with a straight edge out to about 20 inches of draw then using a mirror till final draw. Bows keep taking set regardless of how I do it. Decided to make one more D bow, since i couldn't bring myself to making a handle bow despite my earlier rant about them(just didn't feel right to me). I WAS VERY CAREFUL ABOUT NOT STRAINING THE WOOD, PULLING ONLY TO DESIRED WEIGHT, WATCHING FOR HINGES/STIFF SPOTS. Here's what i got....
This tiller looks about right for me. Full compass/circular tiller, bendy tips. I may be holding it not in the center. I haven't wrapped a handle or finished it yet. This one is 69 inches tip to tip pulling only about 42#@28 inches. Backed with a strip of linen because the grain wasnt great.
(http://i63.tinypic.com/2cseao4.jpg)
Set is close to like 2 inches.
(http://i68.tinypic.com/m7dpog.jpg)
Here is an even longer one. 71 tip to tip pulling 51#@28 inches. This one's tiller isn't particularly good. Has stiff tips(something I don't bother doing anymore). Would have been better tillered with bendy tips and more bend midlimb. But it bends evenly and shouldn't have taken this much set at that length of wood IMO. GRIPPING IT A BIT TOO HIGH ABOVE CENTER IN PIC. Elliptical tiller may have been better for this long of a bow, but I find the circular one easier to picture in my head and design.
(http://i63.tinypic.com/122bsqd.jpg)
Set is excessive.
(http://i63.tinypic.com/2ainbl5.jpg)
Front Profiles. Simple design. Handle widest part of the bow. Last 10 inches or so taper to the tips.
(http://i63.tinypic.com/r2iwsw.jpg)
MY SOCKS DON'T MATCH. I NOTICED. And you get a beautiful view of what Eastern New Mexico looks like in the background :( No bow wood. Any help or critique appreciated. Happy Labor Day
Dic
-
I can't answer the question, but I can say I've had the same experience with oak. My hickory and osage bows have also taken a little set, but nothing like what the oak and maple ones have done.
-
I have never had much luck with read oak the last one I tried was one of my better tiller job bows but it ended up snapping on the tree it was a 66 in bendy the other was a pyramid cracked that one was designed to narrow , I had herd from others that the kiln dried boards from some of the big box stores in this area were very brittle and from the inside look of wood I believe it ,it was very dry but I have a red oak stave in the shop may try some day ,just collected much nicer wood so never tried it yet I still have a really nice grained red oak board out there too but just kinda gave up on red oak but that's just me I have seen some nice ones posted here.
-
Just a few thoughts. Your a bit too round in the handle imo. If your set is near the center, that's where you can fix a bit of it. Less bend there and a little more outboard. Some experimentation may be in order. Not a fan personally of red oak, but wider and thinner may help some as well.
-
Yeah, I get set in red oak bows, too. Doesn't seem to matter what length I make 'em or how carefully I exercise them while tillering. Take it for what it is.
On the flip side of the coin, your tillering is getting pretty dang good. So go ahead and puff out your chest and strut a little, if that helps!
What part of N.M.? I lived in Tucumcari for a little while once upon a time.
-
Slim I agree that the second bow bends too much in the handle. Outer limbs are a little too stiff. I think the first one is tillered exactly as I'd want a D Bow to be though. Slight flex in the handle. Went and shot the first one about 50 times. No noticeable handshock. Second one has a bit of handshock due to outer limbs/tips being a little too heavy.
JW- Clovis, NM. About an hour and a half from Tucumcari I think. There aint shit out here man. Im sure you know. The sunsets are nice I guess.
I notice that the Red Oak starts to take set immediately upon stringing after the long string is good. I'm of the opinion right now that it is just a really crappy bow wood. Seen some good Red Oak bows on PA though, so idk. Maybe wide and thin is a better design like Slim said..
-
Not all boards are equal within the same species. The heavier boards with a waxy texture seem to be a bit better.what slim bob said,maybe goggle Tim bakers mantra and that should help with set.flipping the tips will help with performance but will place extra strain on the back to an uncertain end?heat treating will do the same.2" of set on a ro. Board is not terrible though.
-
I second above comments, both about oaks naturally taking more set than other woods and a need to moving the bend away from the handle and into the limbs. I'd also suggest making oak bows a bit wider, and perhaps heat treating them if you have the capacity to do that. It can help.
-
It's actually mostly because of your tiller. The bow is taking set where it's most strained.
However you shouldn't take total set as a judgement as to whether your bow is any good or not.
-
Is a bendy handle bow that is not flat when drawn incorrectly tillered? That seems to be the consensus. These bows are much more circular than elliptical. I can see this becoming a problem if handshock arises, but i don't see why it should cause set. There is less strain on the outer limbs since the inner limbs are working a bit more. This would lower strain on the wood rather than increase it, I would think.
-
No, the bow is bending too much in the handle.
-
I would say in this case it's less about your tillering and more about design. That's not said to contradict Pat in any way, as tiller is part of the design. I think your tiller looks pretty good. Better on the second and it took set as well. That tells me you could not have done much else at those dimensions with Red Oak and improved on it much. You need to tinker with the width of the belly some. At the same time, and guys may slap me around for this, but circular tiller may look pretty, I don't find it to be ideal on longer bows. I want the bend outboard more so. Short bows will for me get a more circular bend, but at that length, no sir. Just a little flex. Your bows looked good 3 years ago, bend wise. Even better now. You gotta either change the design, the wood, or learn to embrace your inner set. 😁
Check that. Better on the first.
-
Moisture?
back not trapped?
It looks like the handle is bending more than the rest, which would mean more strain?
You can't find white oak? No hard maple? No lumberyards?
-
This would lower strain on the wood rather than increase it, I would think
yes it would in a overall sort of way, but strain can be localized along a bow limb, or in the handle area as the case may be.
a similar bow that I built a few years ago gave me the same sort of problems, and seeing at 20", what will become a circular tiller @ 28" took a few tries. tracing the first and second bow curves ( @ 10", and @ 20" ) on a piece of sheetrock will make the third to easier to see as you are tillering out.
-
With the profile mostly parallel and then narowing to tips you should have a more elliptical tiller imo
-
With the profile mostly parallel and then narowing to tips you should have a more elliptical tiller imo
bubby- i have always had a hard time understanding profile vs tiller shape recommendations.
are you saying that....with a constant thickness taper..... the tiller shape will turn out more elliptical with that back profile?
or perhaps
with that back profile, that he should tiller thickness accordingly, to achieve a more eliptical shape?
or something else ?
willie
-
Willie, we're turning bowmaking into rocket science it seems like.
Okay. Decided to whip another one up. Here was another board that was half finished, I tillered and shot in today. I didn't touch the handle area. It was left as thick as the board was. This one appears only slightly more flat in the handle. Still a lot of set taken, little more from midlimb towards the outer limbs now.
62 in ntn. 48#28 in
(http://i66.tinypic.com/2d2avwk.jpg)
(http://i65.tinypic.com/2ln73lz.jpg)
-
that seems evenly tillered, a touch less in the center. If you want less set with that red oak, your going to have to go longer or wider I guess.
btw, how do you determine your weight goal, before you start tillering?
-
Have you tried putting one on a caul with 2" of reflex and heat treating it?
-
Shotgun Willie- I think you and a few others are right. I think longer and wider is the only way to go or drive a few hours to find some real bow wood. For these boards, the grain usually dictates what weight I'll shoot for. If the grain is decent, I'll shoot anywhere from 45-55#. If it's bad, 40-45#.
Bubby- A caul? I just googled that and got some really disgusting images. I've never bothered heat treating. Only reflexed one or two bows in the past. But if I have to stick to Red Oak, I may have to start.
I may have to snag some of these ornamental planted trees in the night.
-
I think it's a form, a thick board so you can clamp the red oak into reflex while heating it.
Or I guess you could maybe reverse brace instead? but it'd warp the wood while you heat it i think
-
A caul is a form with the desired shape that you are trying to achieve, i will see if i have a pic
-
(http://i623.photobucket.com/albums/tt320/bubncheryl/Mobile%20Uploads/20160221_165826_HDR_zpsclekcllm.jpg) (http://s623.photobucket.com/user/bubncheryl/media/Mobile%20Uploads/20160221_165826_HDR_zpsclekcllm.jpg.html)
This is a caul or form, i use the piece i cut out for heat treating
-
but you'd only have the back exposed in that one..
-
Yeah like i said i use the piece i cut out, the negative pc that exposes the belly for heat treat
-
(http://i623.photobucket.com/albums/tt320/bubncheryl/Mobile%20Uploads/20150212_151000_zpstklgxerx.jpg) (http://s623.photobucket.com/user/bubncheryl/media/Mobile%20Uploads/20150212_151000_zpstklgxerx.jpg.html)
Here's one
-
OH doh
thanks
-
Just my .02. If you are tillering by stringing the bow, and pulling with a mirror, how can you be certain that you aren't stressing the bow beyond the desired draw weight? Also, What is the weight of the bow at brace, if the bow is at the highest tension at brace, then you could be getting all of the set from bracing it alone. I by no means have the experience that these other guys have, but I feel I have a basic understanding of how to do things, even if i don't translate that knowledge to action.
-
It's quite simple really! I'm surprised nobody has mentioned it.
Yes your tiller was incorrect for the bow design before and you still need to work on a proper elliptical tiller. The reason being that any wood at any given thickness can only bend so far before taking set when released. Make it thinner - it can bend further before taking set. Make it thicker and it can now bend less before taking set. Your bow has a thickness taper - any bow that tapers in thickness along its length MUST bend progressively further as it gets thinner. This concept is absolutely key and especially so when you start using woods that can't shrug off tiller mistakes like osage etc....
The 'problem' with red oak and why it takes set like it does is that it is much stronger in tension than it is in compression. Think of tension and compression properties as two weights on a seesaw - you want the weights equal for both to get a fun ride! Same with a bow - when it is bent the wood gets stretched and it gets compressed - the kicker being that most woods are stronger in tension than compression. So the stronger (actually it isn't 'strength' it is resistance to bending) tension side throws excess stress onto the compression side. As the resistance to compression isn't as great as its resistance to being stretched. Therefore you get set. Set is overstrained bellywood cells that have been crushed past their elastic limit and can therefore no longer spring back.
the way to get around this mismatch of properties is to make the working surfaces proportional to the particular woods set of properties. You can do a simple bend test before starting to work out how your wood behaves and use the information accordingly.
Red oak can make fast, durable, low set bows.
I bought a couple of boards of it years ago and made a whole bunch of pyramid bows and gave them to my friends. They are all still shooting very well. Don't be down on red oak! Just learn how to use its inbuilt properites to your advantage :) I made the back 60% of the width of the belly.
-
Thanks for the advice & info!
-
Curious what your bows weigh. I show them projecting out at about 13 to 14 oz for a 70" bow drawing 45#. A rounded belly would also contribute to set. It really doesn't take much set on a full compass tiller to add up to 3".
-
So Mike, to sum up what you said...
For red oak, I should make it thin and wider or if it's narrow and thick, then tiller it so it bends very little in the inner limbs, making it bend more midlimb and to the tips--elliptical or even slightly whip ended?
Unsure of physical weight, Badger. I'm limited on my items in this small apartment.
JoJo, I've made enough bows to be able to gauge the weight I am at When using the mirror only method. When using a stick, however, I do use a fishing scale to never exceed a certain weight.
Anybody remember this guy? Druid. His bows were my inspiration. Would this tiller be more suited for narrower red oak? Less bend inner limbs, more toward the outer.
-
I think you are doing a good job with what you have to work with. I used to cringe if my bows got a bit of set, no more, I don't worry about it if they are good shooters.
-
Would this tiller be more suited for narrower red oak?
it might make a difference in how it feels in the hand as you shoot, and as Eric says, some of what make a bow a sweet shooter cannot always be easily measured with a ruler.
my guess is that by working the inner less, (and making the outer work proportionately harder) it will still require more length or width to make your desired weight without set. Trapping could help as Mike says, and it would be interesting to see what you come up with, all other things being equal.
Are you experimenting out of a curiosity about the limits of red oak? Other than making a bow with "less set", what are some of your other design goals? Seems like you have a good eye for smooth curves.
-
Would this tiller be more suited for narrower red oak?
it might make a difference in how it feels in the hand as you shoot, and as Eric says, some of what make a bow a sweet shooter cannot always be easily measured with a ruler.
my guess is that by working the inner less, (and making the outer work proportionately harder) it will still require more length or width to make your desired weight without set. Trapping could help as Mike says, and it would be interesting to see what you come up with, all other things being equal.
Are you experimenting out of a curiosity about the limits of red oak? Other than making a bow with "less set", what are some of your other design goals? Seems like you have a good eye for smooth curves.
I started developing an eye for those smooth curves as a young man. Now that my hair is greying and my middle spreading I make bows instead.
-
Willie- I'm limited in wood choice living in the high plains desert right now, so I'm trying to make this Red Oak work for me. I'd like to make a fast shooter with limited set pulling at 50#. I may either leave the next one full length-72 ntn and tiller so the inner limbs work very little, or go for a wider board and make a shorter(60-64 ntn) bendy handle pyramid bow. Thanks for the advice to you and everyone else.
JW- You've gone down in the history books with that one.
-
I remember Druid well. I dont know what happened to him. He was a fine photographer and bowyer. His wAr bows wete amazing and his wood quality was never pristine. I wish I knew why he dropped off the internet?
-
I add in reflex before tillering. If you start bending a piece of wood that starts off stick straight, it's going to settle in some.
-
If you are working with red oak keep the belly flat. I have done countless red oak bows that have taken very little set. Most of mine are about 64" long, 8" stiff handle and fades and 50# and 28". But they are much wider than yours usually about 2" wide. If I am making it from 1 1/2" lumber I use a bend through the handle design and go about 68" long. I let the mass weight dictate the tiller shape. If I am running down about 13 or 14 oz I use a full circular tiller, at 16 to 18 oz I start getting a lot more elliptical with the handle only slightly bending. Most of the time with red oak 1 1/2" wide will call for a slightly bending handle.
-
I remember Druid well. I dont know what happened to him. He was a fine photographer and bowyer. His wAr bows wete amazing and his wood quality was never pristine. I wish I knew why he dropped off the internet?
Saw on local Serbian forum that it was for personal reasons, not sure if he even builds bows anymore.
-
So Mike, to sum up what you said...
For red oak, I should make it thin and wider or if it's narrow and thick, then tiller it so it bends very little in the inner limbs, making it bend more midlimb and to the tips--elliptical or even slightly whip ended?
Thinner and wider will give less set because the wood is strained less. Don't try to make narrow and thick red oak bows... Period! To make narrow and deep bows requires an elastic wood ideally with low bwending resistance eg. yew.
No you miss read what I'm saying about tiller shape. You must remember these things are quite subtle. I most definitely do not mean whip tiller.....I also didn't say that it should bend 'very little in the inner limbs' - again tiller advice is subtle. If you did what you are suggesting you would have the same problem but your set but would in the outer limbs.
Another way to tiller literally any any design is to watch where the set appears along the limb. You should have set. Where that set is shows you how you strained the wood. Set should be virtually non existant in the inner limbs. A little mid limb and the rest in the outer limbs.
Trapping works very well on these tension strong woods. Ignore at your peril!!! HAHA!
Also start bend testing your wood before starting let the info you get determine how you design and layout your bow. Think if you were designing a bridge to hold a certain load....a key thing you would do is test the strength of the materials you had to make the bridge. Steel would make a slim, sturdy bridge and lots of triangles would useful. Stone would be different and a wooden bridge would be different again....however if designed correctly all three bridges would carry the load. Design, design, design.
It is all about understanding the particular piece of woods properties and THEN designing the bow.
I suggest getting the Traditional Bowyers Bible series of books. They have all this information :)
I would also not change profile/length etc until you have this one wired. Then move on. If we keep flitting from one thing to the next it can be hard to see what lessons the wood is trying to teach you.