Primitive Archer
Main Discussion Area => Bows => Topic started by: zoomer on October 03, 2019, 08:24:14 am
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I want to make a D bow as written in TBB v.4. I'm using birch. Perhaps silver, but more possibly, some local specie/subspecie (in Russia, Ural) I can't even find a description of. My arm span is 70 inches. Draw length is 28" (perhaps a little over, since I use the "thumb draw") If I make the bow 66 inches long, will it blow? The limbs should be wider? If so, by how much? I am aiming for 45 lb. draw weight.
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You are in the Urals of Russia? ???
I don't have experience with birch but remember reading of it being used. I've just been given this resource, perhaps it will be helpful for you...wood-database.com
It looks like Silver Birch comes in around .5-.6 for specific gravity. 66" is long especially if you are going to make it bending through the handle. For considering a 29" draw I don't see why you couldn't go 62" long without trouble. If it were me, I'd consider a wider limb at 1 5/8" or 1 3/4" and narrow the grip a bit...leaving it slightly bulbous but bending. Heat treat the wood, I'd figure...
Hopefully people with experience will chime in. Good luck.
P.s. Even at 60" of length...I wouldn't call it a short bow.
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i just did a bow of silver birch, which commonly is not said to be a very snappy and compression-tolerant bow wood. It is 64" with stiff handle and about 45#. I did heavy heat treating which seems to help for the doubtful compression ability and snappyness. a bendy handle should be possible @ 60-62". But do heat treat the belly, build wide and take care about the transitions at the grip whre it maybe should a little narrower for comfort. 2 pennies from me
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Parnell,
yes, I live there. In the city. But for summer I live in rural area. There's not much bow woods. Birch, which is plentiful, GIANT larch trees I would like to turn into 100+ staves :D And some other tree I cannot identify, with almost black, scaly bark. Perhaps it's ash. I would look into that. I want the handle to bend only slightly.
So a bendy handle permits the bow to be made shorter than the flatbow of similar draw weight and length? If this is true, I would start making just D bows. My first bow (finished a couple of weeks before), of birch, was a flatbow. I had a hard time tillering 2" limbs (could have made it 1-3/4"). And you have to worry about the fades, the narrow grip, which I have made too short. And for that reason, I want to try a D bow, which I heard are easier to make. I don't want to heat treat as I don't have a vise, a caul, and a heat gun (which are fairly cheap). I imagine it's easy to heat treat with the gear and experience.
So, here's my take: 65" ntn, 1 5/8 limbs, with a straight taper to 1/2 (or a bit less) nocks from midlimb. 45# @ 29". Would that make an efficient, durable bow without heat treating? I'm making this bow for hunting. My stave has a slight crown. I see some "paradox" (if I'm using this word correctly) in this crown thing. I don't want to make the limbs wide because of the crown. But a wider limb makes more wood for energy storage. But then the top of the limb is more strained and the edges don't work much!
I'm sure I will stop asking such questions with experience.
On the picture, the outline is not my just proposed dimensions.
(https://i.postimg.cc/xjZjLN2Z/IMG-20191003-203412.jpg)
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I've never used birch but I wouldn't worry about that crown. I commonly use wood that is crowned a lot more than that.
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No it will not make a good bow with your draw at that length with out heavy ,heavy belly heat treat as said above. And for Birch the wider the better. I have 2 in the basement right now I have been working on.My wife can post pics later if you like. They are 2 inches wide coming off the fades to 3/4 inch at the tips. The one I have nearly finished is 58 inches long for 26 inch draw on a good day, and is close to 45 lbs. Started with 4 inches reflex on a form.It has now 1 inch reflex, and I keep heat treating it to hold it their. When I am totally finished with it will probably have a little string follow. If it does I will flip the tips a little, and heat treat again. The handle is bending a little in the last inch ,or two of draw. Start at 2 1/4 wide to 3/4 at the tips, and work from their. Use your wife's hair dryer, and use a make shift form, 2 by 4 flat with a 2 by 4 on end in the middle. Clamp the tips ,and heat treat the hell out of it. My 2 cents.
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bassman,
Of course I would like to see these bows. I really don't want to heat treat it. I will make it wider and longer: 2 inches wide limbs tapering midlimb to 1/2 tips. Perhaps during tillering I will narrow just a little bit.
Now I will turn this thread into a build-along ;). All critique is welcome.
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May I ask why you are against heat treating?
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Parnell,
I'm not against heat treating. I thought I can just widen the limbs, make the bow a bit longer and here you go -- no bothering with heat treating. Bassman said I could do it with a hair dryer. I will do it. And post photos
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A hair dryer will not work, not at all. Save your electricity for your lights.
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Most heat guns vary between 750 - 1200 degrees F. Hair dryers get to 140 degrees F at most.
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Hey pearl , I,m telling him to heat treat it some how . Over a fire, with a propane torch, or what ever. Never used a hair dryer so you could be right. Fact is that belly needs some heavy heat treat with Birch as well as some other sub par woods to get a decent bow. We all prefer clean premium woods to make premium bows. I know you do. Doesn't always happen, so we use what we have. He should make some forms, and buy a heat gun any how if he plans on building more bows. He is not heading advice anyhow so I am done.
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May be you have some better tips for him with that wood, and he will listen to you since you have a reputation for building a good bow. LOL
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I don't have much of a reputation short of using my smart azz mouth when I see fit. I agree, it needs heat to be at its best. I have seen my good buddy temper an elm bow over red hot coals, worked like a dream.
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I finished a 58" Birch self bow this morning.It is 44 lbs. at almost 26 inch draw, and shot a 430 gr. arrow through the chrony at 149 fps average. Wonky as could be both strung ,and unstrung though it is tillered right, and shoots good.Over all weight is 14 ozs. I will get my wife to post pics here when she comes home.
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I've never used birch but I wouldn't worry about that crown. I commonly use wood that is crowned a lot more than that.
I agree, I use birch with crown like you have in the pic. of course birch here may not be like your birch, and a lot depends on the tree itself as for how much it will take. I like your plan, and would watch for set developing as you tiller. you can always lower you weight goal or temper the wood if you run into difficulties.
a follow along sound cool!
you will certainly get a lot of comments and help if you post pics along the way
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X2 on what Pearly is thinking...if a heat gun is difficult to come up with then get some hot coals. Be all authentic, also.
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Set is not failure, it is natural...It is our nature to fight it though...Can't go wrong with some heat on Birch...My friend Rich made some great Yellow Birch bendy bows...I have one of them that was not heat treated and it has 1" string follow @ 57"
Don
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Don’t know anything about Birch. But a 66 inch working handle bow can be ideal. I agree with DC that the high crown is fine. Preferable in some cases. The most remarkable bow I ever made, so far as my opinion goes is a 66 inch Osage with a working handle. High crown, knots on top of knots. The onlyest way to keep it together was go long and spread the bend out. 70 some odd pounds at 27 inches and sweet as honey.
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Working on it. No vise. My rasp is dull (after rasping ONE bow). Width is about done. 2" mostly. Maybe when I sand it (some places have rather deep hatchet cuts) it would be a bit less. But no taper yet. Now reducing thickness with a chinese hatchet. How thick the handle should be when I put away the hatchet and start using the rasp? The narrowed part on the limb had a significant ring violation. So I decided to just rasp it away. Having enough width, I consider this a correct problem solving. The stave has some twist and deflex also.
(https://i.postimg.cc/FRC6fwyz/IMG-1783.jpg)
(https://i.postimg.cc/bwNptfbH/IMG-1782.jpg)
(https://i.postimg.cc/Y9mFgyZ8/IMG-1781.jpg)
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I may heat it on an electric stove. It's big and is in the kitchen so it will be hard to clamp it. I'll try though. Or just keep it over with hands.
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If it’s hot enough to eventually scorch wood it’s probably hot enough. It’s better to have something too hot so you can moderate temperature over distance. i’ve bent crooked bows into shape over an electric stovetop, that worked well enough. I’ve never done a full heat treat on the stove but have seen it on youtube before. Can’t remember who it was. Just keep things moving so you don’t burn the bow.
A rasp should last for many many bows. If you feel like you’re swimming in an ocean of rasping maybe you need a tool that fits between your hatchet and the rasp to remove medium amounts of wood, like a spokeshave or drawknife. Farriers rasps are nice because they usually have a second handle for extra pressure on the cut stroke. Make sure you’re not putting pressure on the return stroke because that’ll dull a rasp much faster.
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I haven't put pressure on the return stroke. The rasp is very cheap. The hand tool market is very poor where I live. I have a German half round rasp, a round one, and a Russian file. The handle on the round rasp is not fit parallel to the iron! Brands from Europe, but made in China... There are good rasps though (not made in China) online. The draw knife would be useful, yes.
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I have a mueller drawknife that’s made in Austria if you see one give it a try. I have one and really like it I got it for $50. Not sure how available tools are there I had to order this one from a supplier not directly through mueller.
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Just found 2 major ring violations. Paul Comstock wrote in TBB v.1, "Other Bow Woods":
It is certainly not to be recommended, but I have made bows like this and leaving in the gashes from the draw knife. And the backs of these bows are in great shape!
Should I leave it as is?
(https://i.postimg.cc/tJh2J1kR/photo5246695877035273132.jpg)
(https://i.postimg.cc/XJ5g1ZTK/photo5246695877035273133.jpg)
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i don't see any relevant ring violations - you are fine - sure it's a good idea to integrate that pin on the second pic completly in the back =» as you already did with the pencil lines - leave some extra wood there on the side as the grain flows around that pin (-S go on!
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i don't see any relevant ring violations - you are fine - sure it's a good idea to integrate that pin on the second pic completly in the back =» as you already did with the pencil lines - leave some extra wood there on the side as the grain flows around that pin (-S go on!
I agree with simk, a ring violation is not a natural abnormality, but a damage on the back caused by carelessness when removing bark.
consider heat corrections when the stave is much nearer to being final thickness and width. The up and down in the back is typical in birch and I never try to remove it, I just work with it. Does comstock show a sketch of how? not all twist has to be remover to make a shooter either
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Here is some pics of a 44lb,at 26 inch draw Birch self bow I just finished that tillered Ok, shoots 149 fps average with a 425 gr arrow , and is the wonkiest bow I have ever built. Top limb does a nose dive,and strung ,and unstrung profile is horrible. I have put a couple hundred rounds through it. No set, but no reflex . 2 wide at fades to 3/4 at the tips at 58 inches long. Heavy belly heat treat, and built green to finish in less than 20 days. I built it on a uniform caul from the beginning, but this is how it turned out.
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looks like a challenging bow to tlller, bassman. could you post some more pics? perhaps in a dedicated thread? I would like to comment more, but the OP might feel like his thread is drifting off topic.
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zoomer, I asked if I could post some pics. You said it was Ok. Sorry if I stepped out of line. I thought it might give you a little insight on Birch wood. Willie Pm me. Pat B delete the pics if I am out of line. I had good intentions, and was just trying to help a little, and I am glad Pearl corrected me on Hair dryer deal.Never used one ,but it seems like you have lack of resources. Hope your bow turns good, and you hunt, and shoot some game with it. Good luck.
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bassman,
Thank you for the pics. With time, I'll have all the setup. But for now, I'll use the stovetop for heat treating. Right now, I am rasping the stave to width.
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Good luck ,and stay with it.
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zoomer, I just finished, and shot the sister stave bow this morning. Profile is much better. Same specs with same arrow. This bow shot 153 fps. Inch of reflex, but had to do multiple belly heat treat to get it. Still a little wonky.I think because , both bows were made from a large sapling, and not a large tree trunk. Both bows will work fine for deer sized animals at 15 yds, and in. Here are some pics.
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bassman, your bow is nice. I see you have a long working limb and the tips are a bit wide. I've heard about the long non-working outer limbs (for low string angle) and the low tip mass for efficiency. But as I see, you haven't included all these tricks and your bow still shoots great!
I think this is not how build alongs are made. I guess you just invest all your time on this for a couple of consecutive days and finish it fast. Still working on it. Been a bit busy. Took me 3 months from tree to my first bow (and I quick dried!). This one (I hope) will be faster to make, but I am slow without a vise (which I may get soon). Bear with me.
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The bow only weighs 14 ozs. with the string at 58 inches long, so I don't concern my self with mass with this wood. Once I get 1 on the tillering tree I get it finished quick. This is the 4th one in three weeks. The other 2 are Elm. I am retired ,so their are days I work on them from early morning to late at night. If you get you bow tillered right with no set at 28 inch draw you should have a good shooter. My last Osage bow was 1 and a quarter at the fades to less than half inch at the tips,45 lbs. at 26 inches, and 60 inches long. That wood will handle skinny bows, and it does cut heavy mass which that wood is. Keep us posted.
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Sorry it takes me so long. Got myself a vise. The tips and the handle are almost finished. I will not form them entirely now, as this stave has serious string alignment problems. It's 68 inches long and the narrow tips are 9 inches long (perhaps I will cut an inch off from each side later). The tips don't have to be dead stiff I think, or a least some portion of them. The handle is 1.18 inches wide (3 cm). The limbs are a little over 2 inches after removing the tool marks. As I said earlier, it has significant deflex.
I want to bend it out to some reflex during heat treating (should I? How much reflex?). Now I think I should proceed to floor tillering.
Also, how can I secure a bow on a caul during heat bending without clamps? Tie a knot? Wouldn't it come loose? And should the caul be as wide as the bow or a narrower one will do?
(https://sun9-17.userapi.com/c855136/v855136082/15d9bc/7mS2QyJzhfY.jpg)(https://sun9-34.userapi.com/c857236/v857236082/3d714/7TpaZHM8cIQ.jpg)
(https://sun9-22.userapi.com/c858428/v858428082/df91c/744RAA3b-vA.jpg)
(https://sun9-34.userapi.com/c857120/v857120082/3c892/HtQgCWnSr90.jpg)
(https://sun9-46.userapi.com/c855220/v855220082/15dafd/yEwjpoEMg6k.jpg)
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String alignment will be your biggest obstacle. If you get the levers narrow enough to matter, and the alignment is off, it will be a problem. You should more than likely get all the bends done in one session, meaning remove the deflex and fix the alignment at the same time. You can do one limb at a time if you want. I typically do. No need to get fancy on the caul. A 2X turned on its side is enough. I would get that done as soon as the bow is flexing some, before going much further. I use clamps and cant imagine doing this without them. Get creative I suppose. Get the heat treating done while it is secured in place as well.
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Forgot the image.
Slimbob, thank you for the help.
This stave came from a nice, straight tree. My first bow is as gnarly as this one. Both of them have some pattern: first it reflexes right from the handle and then proceeds to a greater deflex.
(https://sun9-13.userapi.com/c856020/v856020082/157e3b/-Pw8TjqrBng.jpg)