Primitive Archer
Main Discussion Area => Bows => Topic started by: PlanB on November 01, 2015, 05:51:26 pm
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I keep wondering if I can make a decent bow from the black birch that grows here (Betula lenta). The first two I tried from that, a board bow, and a sapling didn't work out. The second almost did, and lasted a short time.
My last (third) bow from an elm stave did work out, and I'm enjoying shooting with it every day. I've learned a lot through these three, and I do know my first two didn't work because of my own inexperience in both tillering and design. So there's still this nagging question in my mind, can I make a successful birch bow from what I have here?
I have a really nice straight grained birch stave cut, but that will take awhile yet to dry, yet. So not much I can do with that now. But I had also cut some birch boards on my bandsaw, and I stacked and stickered a few months ago. So I thought I might have a go at a board bow. I checked today and they're down to the teens in moisture content, so I thought I'd rough out a board blank and bring it indoors to dry it further.
I picked a board that had straight grain and also had flat grain -- the second flitch cut on that particular log.
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It will be interesting to see if you can make a bow from it, best of luck!
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I drew out the blank with a pretty big margin, in case I got any checking or other problems. I'm thinking a bow about 66" long and 2" wide limbs, tapering in the outer foot, similar to my elm stave bow. I'm thinking it will be interesting to compare the two.
I cut the blank to68" long, 3" wide, and tapered the ends to 1". I should be able to fit the finished bow in that, once it dries more. I did notice about 1" of reflex (toward the bark side) and considered strapping it flat to dry. But actually, I'd like the reflex to stay, so I'll just keep an eye on it s it dries.
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Thanks Bowandarr0w473 -- it's either going to work, or not, I figure! I kinda hate to give up on something, unless I'm really sure I did all I could to figure it out.
I've been re-reading Paul Comstock's Bent Stick, and a white birch bow is mentioned there, which performs very well. But reading through it again this time, I noticed it was sinew backed -- hadn't remembered that. I also read a tantalizing bit where he says he had a "dark" barked variety of birch he'd wanted to try, but it was lost somehow before he had made a bow from it.
I also started thinking today that I might as well also try a white ash bow, since I'd cut ash boards at the same time as the birch. So I pulled out a similar edge flitch with clear straight grain, and used my first blank to mark out the ash.
Altogether I will end up with similar dimension bows of elm, birch and ash to compare -- I hope.
Here's the ash board:
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When speaking about the ash board, I see major violations everywhere but off to the right side, that is the side that you are thinking be used for a bow correct?
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Hmm, bowandarrow, doesn't a board bow almost by definition violate the back?
I thought it wasn't the fact of violation but what the pitch of the grain was. From the side the grain is really parallel to the back. The figure is a very slight variation. But willing to live and learn, if I'm wrong here.
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Birch makes a good bow and so can ash i have a bow from halfeye that i believe he said was green ash nice shooting bow that i have had for some years, birch I've even used as a backer on a walnut bow that was a sweet bow, don't worry you'll get some bows there
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The fibers must run straight down the board on every face, especially the back I think, that's what I always looked for and it never let me down, I tried a bow once that had three violations on one limb on the back at a sharp angle and CRACK. Never had such a problem with totally straight grained wood, after that I stuck with stave bows, don't much like making board bows now.
But, like I said, I see a bow off to the right side, but I see the middle part as unusable.
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Plan B
Hmm, bowandarrow, doesn't a board bow almost by definition violate the back?
the run of grain stays between the rings. therefore ring lines can tell you a lot. If the grain spirals around the tree, you may not see it looking at the ring lines, but if the flat sawn board splits on a diagonal, then you can see spiral runout. If the spiral changes directions from year to year, then take your chances I guess. Some find that if you split a flat sawn board then glue up the planed faces, after turning the pieces 90, then you have straightened it some. Some swear by rift sawn so that you are not putting earlywood on the back or belly. More of a problem with ring porous ash than ring diffuse birch.
willie
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Thanks Bubby, Willie. I could lose this board and pick another board in the stack for the ash, with any grain orientation, depending on where it was sawn on the log, even quarter sawn.
But, just to clarify, the ring lines on the sides of this board are very straight, evenly spaced, and nearly parallel with the face. To me that would mean there isn't any spiral grain. If there was spiral grain, I think I'd see angled ring lines with a positive angle on one side and the opposite angle on the other. Like if you ripped a board out of a barber pole. Viewed on edge the stripes would angle.
Also the figure on the back runs down the middle of the board and doesn't curve, which would mean the tree's camber was also straight and was located over the board centerline. The figure does show the center grain wanders up and down a little (the rings are finely spaced so even a tiny amount of wander will create figure), and I don't know how serious that is. But almost all ash will show that figure in a flat sawn board. On this one, the figure is relatively even in width, rather than tapering, meaning that the board was cut parallel with the bark, rather than angling through the log. I dunno seems to me it's the best I could ever get from a flat sawn ash board.
I can imagine quarter sawn would give a more homogeneous back, but I just wonder.... seems like people often make successful ash board bows, and I wonder if they are all quarter sawn.
BTW the photo of the end grain is confusing because I turned the board over apparently, compared to the overhead view (of the back).
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I do think that halfeye xuts his own board stock and usually i think it is fully quartersawn
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Hmmm, maybe that's the way to go then. Bubby you've done a lot of board bows, right? But the one in your how to is maple, not ring porous I think. I think George Tsoukalas did red oak, and that's pretty heavy ring porous, right? Does he use quarter sawn?
Maybe the flat sawn board bows use backing -- that would make a difference. I don't want to do that, so maybe quarter sawn is right for an unbacked board bow in a ring porous wood. Don't know -- never seen that as a rule before. Maybe it was just assumed....
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Rings should be parallel on the sides and the back. They ideally should run the whole length of the board. However, on a plain or flat sawn board the back ring lines may come to a V. This is quite acceptable
That's from George Tsoukalas board bow description on his website. Maybe I'll go ahead with this board anyway, just to see what happens. I kinda remember something similar from the TBB's, but I can't remember which one it's in.....
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Flatsawn bias full quarter will all make a good bow, flatsawn you can take it to one single ring if you feel like it and no body will know it was a board
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Might be the self bow guy in me talking, but I would just chase a ring on that ash board
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I was thinking that, wizardgoat. Taking a careful look at the fresh cut edges of the bow blank I found two places where the grain hooked, and I've finally decided this piece is a no-go for me. Bowandarrow473 I think you were right to question me on this one -- thanks, one more lesson learned here.
Bubby, I believe what you said about all being possible. But of course, the rub is, is the board good enough to pull it off -- especially without backing.
I think a board has to be absolutely perfect for an unbacked flat sawn bow in ash. I think now that good vertical grain (quarter sawn) blank would be easier to find, and the ring runout wouldn't have been a problem unless much more severe.
When you think about it, a bow with vertical ring orientation always creates runout at the edges of the bow, since the bow limbs taper. But as long as the grain is reasonably straight and parellel to the bow, bending is always going to be perpendicular to the rings, so they aren't subjected to shear the way they would have been if flat to the back.
Diagonal ring orientation is going to be a somewhere in between.
I looked for a quarter sawn board in my stack, found a couple, but those both were spoiled by one or two worm holes. So I'm going to give up on ash from this particular tree, for now. I'll wait until I cut a better one, and I'll keep in mind the need for quarter sawing, next time when cutting it up.
The birch looks good so far, and I still have a nice birch stave with the back on, so I'll keep on with that.
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I've let the birch blank dry some indoors, and it's now time to add the handle riser and rough it out for a bow. Looks like I'm probably going to be able to keep it the full length of the blank, 68" since there are no checks in the ends. I'm leaving it to dry further at this point.
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Be careful. I thought I saw some almost circular ring lines in a picture in the foreground. That indicates a knot which is nearly always fatal. Jawge
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Thanks George. I think what you're seeing is the shadow of the bevel on the belly. (If you're talking about the birch photos directly above, and not the ash pictures earlier in this thread.) Because the bow blank is lit from the side, the bevel is casting a shadow, which makes one side look darker in color.
I band sawed the birch blank above, and I cut it from marks on both sides, canting the blank slightly while sawing. That leaves a bevel in the middle of the belly, more or less -- kind of like when you take wood off the belly, by first beveling, then flattening. There aren't any knots in this blank. I haven't flattened the bevel yet -- I'm letting it dry more before working on it.
If you are talking about the ash board earlier in the thread -- I've shelved that one because of grain runout that I found once I cut it down.
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Just an update, I thought it would be interesting to just add the drying progress here. I've checked the weight of the roughed out blank every day and marked it, with the date, in pencil. The bow is in a room with occasional wood heat, though not placed near the stove. the humidity in the room is averaging about 50% Here's the weights in grams and dates so far:
11/5 1045
11/6 1031
11/7 1025
11/8 1014
11/9 1004
11/10 994
That's about 10 grams or 1% per day. Which seems fast to me. I'm surprised at how steady that is, too. I'm going to be interested to see when, and how fast, it levels off. There are no checks, no warping or any change in the 1-1/2" total reflex so far.
Edit: continuing
11/11 986
11/12 984
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Planb
howdo you monitor the humidity in the room. 50% is good for keeping the board at equlibrium, but may be a bit high for getting it down to equlibrium ,unless the wood was fairly damp when you started
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Willie, I have a small inside/outside temp and humidity meter in the room.
I think 50% RH indoors is optimal for health and what we strive for. It will drop, unfortunately as winter gets here.
50% correlates to 9.5% wood MC. In summer both indoors and outdoors are higher and where a bow will be stored and used respectively. The exact numbers aren't important, the intended useful environment is.
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The ash board could be used if you use just one side or the other where you see the end grain is in this orientation/////// about 30 to 45 degrees. This is usually called riff cut. The middle of the board is flat sawn and would need a backing or chase a ring. I've made lots of good bows from riff cut boards.
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use the middle {chase a ring} and use the right side {riff} there ya go 2 bows. :) Tony
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Thanks Fiddler, Tony. This is what I saw on the edge of the ash board once I had cut the plank down more. It's about mid limb. I should have looked at the face ring pattern to realize this kind of hoogie lies under a ring island -- you can see that "island" pattern on the face. I think that's what George was taking about above.
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Just an update. I've been working with the black birch board bow, and gradually getting it shaped with heat, tillering and shooting in. I'm not done yet but I think it's it's getting close. I've left the finish off for now.
I have about 300 arrows through it now, and I think it's going to be a good one, for me. This black birch (Betula lenta) really has a noticeable ringing tone to it when you rap it with a knuckle unstrung. Noticed that even when it was a board. More than my elm stave bow when you rap that. It feels zippy to shoot, too, by comparison. It's holding its shape very well after shooting. I had to deal with a little propeller twist at one tip -- I almost have it all out. I don't know the final draw weight yet, but I think it's going to be close to my target of 45 lbs @ 27"
Here's what it looks like right now, unfinished:
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Looking good
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Looks good!you put the set in the right spot!
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Zippy bows are always a good feeling.
Looks like you put a little heat bend in the tips. Did you do that dry? Did you do the whole limb also?
One place I read recommends steaming for birch, and another place I read that heat treating doesn't work too well with birch. Don't know what to think sometimes......
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lookin good! Tony
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Nice job.Looks like you got the dimensions right for that kind of wood.
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Thanks Bubby!
I think I'd like to try a pyramid bow like the one you showed in your build-along in this same wood, to see what the differences would feel like in a bow. I'm thinking it would be nice if the mid limb was narrower than this one because it's such a stiff wood that it is pretty thin at 2" wide.
The mid limb has ended up only 3/8" thick. That was a hard thickness for me to tiller evenly tapered to the end. And it tends to twist easily. I'm thinking a pyramid might be easier / thicker, and maybe it could even be lighter than this one. Though it isn't too bad now -- 18-1/2 oz now on 64".
Also, maybe I could have gone narrower than 2", but I was worried about set with this unknown wood, so I figured I'd start out thin, and wide. Anyway, it's seeming pretty good so far.
Bushboy, thank you. I really admire those short thin tipped elms of yours! Some day I want to make a bow like that.
Zippy bows are always a good feeling.
Looks like you put a little heat bend in the tips. Did you do that dry? Did you do the whole limb also?
One place I read recommends steaming for birch, and another place I read that heat treating doesn't work too well with birch. Don't know what to think sometimes......
Thanks willie, I did heat treat the ends. I did it with dry heat, not real dark, just to bend the tips some. I didn't do the whole bow. The bottom limb I went farther on the limb than the top -- a little stiffer -- thinking about what people said about positive tiller (it's shorter than the top limb by 2") but I think it may be a little too much. I can't tell yet -- just did that today, and waiting to let it re-hydrate -- so maybe it will soften up a little tomorrow, and I'll shoot it more, too, and see what it looks like. I could heat more of the top limb to even it out it if it still doesn't seem right.
I don't know what heat treating will do to black birch in the long run, or how much to heat, or if different species matter -- probably does, as a guess. This is just what I felt it needed for shape -- and it has worked so far for that. It is definitely hardened the wood there. Long run? We'll just have to find out.
Tony, man, I really enjoy your posts and the materials you find and use, it's great reading, so thank you!
Beadman, been looking at your bow, quite a bit! I hope this one works out because there is so much black birch around here, no osage, yew, or even hickory, but if this is a decent bow wood for some type of design, I'll be happy.
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PlanB, where are you located? I'm sure there is some very high quality bowwood in your area.
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Thanks Bowandarrow, I'm in Vermont. I didn't mean to say it was a problem -- I'm enjoying experimenting with what grows right around the house, and there are a few good well known bow woods there, too. scattered elm saplings, and a few hop hornbeam. I'm enjoying trying to make something of the black birch -- since it's probably 50% of the hardwoods growing here, grows straight trunked and limbless for 30 feet. I'm thinking this is going to work well in the right shape and type bow. Just have to figure that out.
I worked on the bow more refining the width near the tips, did a little more heat treatment on the top limb to better even out the stiffness of the top vs. the bottom. And I worked down the handle, because last time I shot, I was getting some bad wrist slap -- -- thickness on the thumb side was forcing my wrist in, with the bow square to the target. I've started to like an unwrapped handle and shooting off the hand, but that means I really have to fit the handle right.
This morning I put another 50 arrows through it -- no more slap. It's shooting more accurately. I think the bow is done, as far as removing wood. I sanded and put a first coat of tung oil on to seal it. Undecided on paint or stain, etc. It tests out to 40# @ 27" 65" ttt, 18 oz.
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Sanded and oil sealed. Five hundred arrows through it. Close to done. Leaning against a yellow birch below, but it's black birch bow.
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Looks good hows it shoot?
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It shoots real nice, Bubby. I don't have too much to compare it to -- my elm stave bow, and a 40# 60" Fred Bear Bearcat recurve from thee 70's. Shoots harder than either and as accurate as the elm stave, more accurate than the recurve, in my hands, at least.
I've had a Chrony on order for a couple weeks, supposed to arrive today, but if it does could be after dark. I could say better what it does once I figure the thing out and try it. Hoping it's today!
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Got the chrony last night after dark as expected, so I couldn't try it out. Today it was cold and rainy, and I had only an older 9v battery, but I was able to give it a try between rain showers. Got thirty arrows off before it showed low battery signal.
The black birch bow shot between 160 and 167 fps on average when I was holding and shooting my best, with 355 gr. carbon arrows. I had a hard time getting a reading with my wooden arrows -- probably because they are light colored. But those that registered were running about 4 fps slower @ 370 grains.
The bow is 63" ntn, 40# @ 27.
(Looking at my picture I think maybe I should be thinking I'm about 26" draw instead of 27? The arrow there was 28-1/2" long)