Primitive Archer
Main Discussion Area => Bows => Topic started by: Shaun on December 10, 2011, 04:25:09 pm
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First, thanks for the positive comments on the couple of recent ELB bows posted. There were some questions and a build along seemed like a good idea. Plus, I have been making these for others and wanted one to play with myself.
The other half of the stave from Timo was about 1 1/8" square by 72 1/2 long. I drew a grain follow center line - this piece is clear but wavy. Then I marked 5" increments from the ends and laid out profile with each segment 1/8" less in width. This makes the center about 1 1/16" tapering to 1/2". The first pic shows this profile cut and the same taper laid out on the side profile. I cut the top lay out square to the back (chased ring) surface.
(http://img.photobucket.com/albums/v613/shaunw/ELBhowto001.jpg)
Make the same tapering layout on both sides and cut with approximately 10 degree lean of the back surface. This prevents cutting too deep on the opposite side where the wood is twisted. After making cuts from both sides you will have a ridge in the middle of the belly.
(http://img.photobucket.com/albums/v613/shaunw/ELBhowto002.jpg)
Application of power rasp (edge sander) removes this ridge and general shaping towards the arched belly shape and general view towards leaving a tapering in both width and thickness from center to ends.
(http://img.photobucket.com/albums/v613/shaunw/ELBhowto003.jpg)
With the bow flipped back side up you can see that this stave is not straight. Since we are headed for a rounded shape (ELB rule is that the bow can be no more than 8 to 5 ratio of width to thickness) it is MUCH easier to tiller a straight stick. A flat bow resists bending sideways - much less so in a rounder shape.
(http://img.photobucket.com/albums/v613/shaunw/ELBhowto004.jpg)
So, onto the cull with heat gun and clamps.
(http://img.photobucket.com/albums/v613/shaunw/ELBhowto005.jpg)
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I like to use a piller tiller system before brace height. This allows me to get back and sit looking at the arc, then mark with pencil and take off wood where there is less bend, flat spots. Here is the stick off the cull with induced backset and nearly straight.
(http://img.photobucket.com/albums/v613/shaunw/ELBhowto006.jpg)
My belief is that you can do little harm to the stave before reaching brace. The bar clamp allows continuously variable draw and is more solid than using a long string on the tree or a tiller stick. Here is the first bending. As always, stop as soon as you can see a flaw in tiller and correct.
(http://img.photobucket.com/albums/v613/shaunw/ELBhowto007.jpg)
I see flat spot in the center and about 1/2 way out the right limb.
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Correct and repeat process until the arc is pleasing.
(http://img.photobucket.com/albums/v613/shaunw/ELBhowto008.jpg)
Still a little flat in the center, just to the left of center, and last third of left limb, but getting real close. At this time I return to the heat gun as some of the original waviness has reappeared during tillering - this is common with heat adjusted wood. These smaller and area specific adjustments are made one at a time on the bench.
(http://img.photobucket.com/albums/v613/shaunw/ELBhowto009.jpg)
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After re straightening, continue adjusting tiller on the posts. I switch from 40 grit to 100 grit on the edge sander and start to work on smoothing and tapering in both width and thickness as the tiller progresses.
(http://img.photobucket.com/albums/v613/shaunw/ELBhowto010.jpg)
When it gets this close I cut string nocks and try first brace. I use the pillers to brace as the bow is still to heavy for push pull hand stringing. Love the moment of first brace!
(http://img.photobucket.com/albums/v613/shaunw/ELBhowto011.jpg)
With this method 90% of the build is completed before the bow is ever drawn past first brace. Now is the time to put it on a tiller tree and/or start shooting it in. As the wood is worked it will change and need re adjusting of tiller. This is also the time to check draw weight and start reducing towards desired finish weight and refining aesthetic lines. Also, minor adjustments of limb alignment will be needed by either heat or tillering (cutting material from off center of the width will make the limb bend towards that side). Here is the bow nearly complete - needing finish smoothing and more shooting in with minor adjustments as they appear.
(http://img.photobucket.com/albums/v613/shaunw/ELBhowto012.jpg)
(http://img.photobucket.com/albums/v613/shaunw/ELBhowto013.jpg)
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My belief is that you can do little harm to the stave before reaching brace. The bar clamp allows continuously variable draw and is more solid than using a long string on the tree or a tiller stick.
???
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This bow is still slightly heavier than the mid to low 50's I want, but final tiller adjustments and sanding will bring it in. Time to shoot it a bunch and get the wood to finish settling in to its working shape.
(http://img.photobucket.com/albums/v613/shaunw/ELBhowto014.jpg)
Another note; I mentioned the ELB ratio of 8/5. The center of the limb is under more twisting stress than the hand held center or the tips, so this area is often shaded more towards the 8/5 flatter profile and the handle and tips left round. This makes the limb cross section progress from round center to flatter mid limb and back to round at the tips in most ELB bows.
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Jack, is that JR pup asking for clarification?
Before bending past fistmile brace height little set or fiber damage is likely because so little deflection has been made. It is yanking a bow back to 20" while it shows tiller flaws that induces set and hinging. By correcting tiller flaws in the very early stages of bend this is avoided. It does leave the wood untested and further bending will create new flaws as the fibers stretch. These need to be corrected as soon as they show during the working in by shooting (short draw) or working on the tiller tree. In the first brace picture on the posts, the arc looks nearly perfect. This will change as the wood works - that is the last 10% of tillering required until full draw is reached.
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Yep, thanks for the clarification.
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I remember you mentioning your tiller system before Shaun. Im glad you posted pics. I have to have one now. That has to speed up the process allot without stringing and unstringing so many times before you can leave it braced and tiller. Thanks for the pics and post.
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That's an interesting tillering setup - I never thought of that...pretty cool
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I like it!!
"piller tiller system"... Why wouldn't it work with a non bending handle?
Looks like a real time saver?
Thank you
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Thanks Gordon, any praise from you (my tiller inspiration to do better) warms my heart.
I wish I could claim credit for thinking this system up. One of my favorite sayings is, "All wisdom is plagiarized, only ignorance is original." So, credit to Brad Merkel - who passed it on to me. It works equally well with elliptical tiller on flat bows and making the posts clamp-on style allows adjusting for shorter bows. I also move them in a little to brace the bow as then I can have the string on the bow with the bottom loop on and the top loop ready to slide up. The top loop must be outside the post to slide. This puts less stress on the bow than bending far enough to get the top loop over the end. It also makes adjusting brace height easy - just reverse the stringing process.
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I like your setup there! Thanks for doing the build allong!
Josh
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Do you put leather in between the tips and your posts on softer woods like yew so it doesn't accidentily dent or ding the back of the wood? Interesting set up for sure. Looks like it works well for ya.
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Shaun:
I agree with Gordon, this is a very interesting concept.
I was wondering if you use any kind of tiller gizmo or do you just eye it?
I have to try this method out on my next bow.
I already planned on making an elb style bow, out of some 3'' diameter pecan trees I cut a month ago.
Could you please post the dimensions of this bow?
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Disregard the dimensions Shaun, I just reread the post and saw them.
I was focused more on the bow rather than reading ::) ,,,, Sweet looking bow
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Finished this one most of the way and added beeswax and handle.
(http://img.photobucket.com/albums/v613/shaunw/ELBhowto016.jpg)
(http://img.photobucket.com/albums/v613/shaunw/ELBhowto015.jpg)
For the wax finish I heat the wood and rub the wax piece along as I heat, use my finger to spread the hot wax (ouch). Once the bow is completely covered, I re heat and use an absorbent clean shop rag to remove excess wax and polish.
(http://img.photobucket.com/albums/v613/shaunw/ELBhowto017.jpg)
Full draw still a little off but will work on it again after its shot in more. Top limb does not want to come to full compass and is complicated by some flip tip profile, twisted grain and a heat straightened woop de do in the last third (see unbraced pic). Its beat me for now, but I'll be back at it later. Happy with bottom limb.
(http://img.photobucket.com/albums/v613/shaunw/ELBhowto019.jpg)
Specs 70.5" NTN 55# @ 28" (1 1/16 x 7/8 handle, 15/16 x 9/16 mid limb, 1/2 round at tips)
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Another just wrapped up. Yew with horn nocks 68" NTN, 43# @ 27" TruOil finish. The measure on this on is 1 1/8 x 1 handle, 1 x 13/16 mid limb, 9/16 round tips. The actual dimensions of each bow will vary because of individuality in each piece of wood, density, modulus, etc.
Sorry about the dark pics
(http://img.photobucket.com/albums/v613/shaunw/ELBhowto022.jpg)
(http://img.photobucket.com/albums/v613/shaunw/ELBhowto021.jpg)
(http://img.photobucket.com/albums/v613/shaunw/ELBhowto020.jpg)
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More about piller tiller posts. Dimensions not critical, just a good solid base that can be clamped and will not move. This set made from scraps around the shop, SPF (white wood or technically Spruce, Pine, Fir) soft 2 x 4's and a chunk of some 5/4 poplar for the base - 2x would work fine for a base. The softer the wood the better for the post as it will not dent/scratch the bow. I rasped out a dish and burnished where the bow tips slides. I believe Brad's set had carpet scraps on the tops.
(http://img.photobucket.com/albums/v613/shaunw/ELBhowto023.jpg)
(http://img.photobucket.com/albums/v613/shaunw/ELBhowto024.jpg)
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Very cool concept Shaun. Your tiller is so beautiful in these last few bows I maybe should look into this idea. ;D This old dog don't mind learning new tricks! ;)
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I'm fascinated by this method. So, do you floor tiller at all or just go right to the pillars as soon as the bow bends at all? There's definitely a spot on one of my workbenches for this setup. :)
George
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It obviously works because your last two was perfect...and it saves some space too.
Perhaps make some from those supports with plastic rollers that you use with bandsaws and planers...
/Mikael
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Have you noticed any handshock at all with your osage bows of this style?
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gstoneberg, I floor tiller before the cull and flex the limbs against the floor several times after each wood removal to help set the change.
dbb, rollers might be tricky because the bow will try to flip if it has backset or is round. I usually flatten a small spot in the center where the clamp rests to help stabilize.
ryoon4690, some shock with light arrows. Much variability in shooting quality with my ELB's much more so than flat bows. Some of them are just sweet, others are finicky. I think this is a matter of fine tiller tuning in-the-hand and limb timing balance.
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Yes Sir!
Thank You for sharing your Build Along and Tillering system.
Regards,
-gus
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Really!!
Great thread!!
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Although your method looks good as well as sounds good. Your still over stressing your limbs. By not tillering to brace height. Ledding to more set and string follow than if you don't tiller to brace height.
Always work by tillering to your target weight never drawing ( ANY BENDING) your bow until you've reached it. Not like your doing by drawing when to heavy like you said. Your over stressing your limbs. Causing set and string follow. Sure you can make a bow like this. It just won't be as good as it could be. Speeds shouldn't be involved in building selfbows.
You could try clamping those stave's down when green like your doing with that bar clamp. Then you eliminate the step of heating the stave to put reflex in. If your worried about speed. Cut it into semi bow forum I use a ratchet strap or hang cinder blocks off the center.
SLOW DOWN you won't regret it and you'll build nicer bows.
Noth trying to change your mine build your bows the way you like, just pointing out your misstakes.
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crooketarrow, I disagree with you assessment of this method.
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Thanks for the build along Shaun. Much food for thought.
Real nice bows also.
Lane
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I don't see how using this set up correctly by the same rules for low set tiller,and by an experienced person who knows not to go past any hinges or desired weight wood incur any more than normal set or stress than a long string on a tree. I as well disagree with crooketarrow.
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This is by no means the only or even a "better" way to tiller, it just an option for early stage tillering. Use of band saw and edge sander is not for the faint of heart and I have ruined several pieces of wood by using power and being in a hurry. In the video of "From Billets to Bows" Glenn uses a power joiner for much of his tillering on yew bows. He took considerable flack for this and his answer was that he was making bows for a living and supporting a family. I have no such excuse, I just love to make bows and learn from experience. One definition of experience is "a long series of non fatal mistakes." I have broken many bows in making and in use, live and learn. I broke a really nicely progressing pear flat bow last week - was not hurt and learned that even in pear a pin knot cannot be cut flush with the back ring - cut it while carefully (but not carefully enough) removing bark with a draw knife. It is my hope that we can all learn from each others methods, mistakes and triumphs. There are several bowyers on this site who have taught and inspired me. Thanks!
(http://img.photobucket.com/albums/v613/shaunw/PearBreak003.jpg)
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Your tiller set up is very interesting. As long as it works, and you arrive at desired weight, length, and tiller profile, who cares how you get there! New ideas foster change. It looks like your bows don't take much set, so I'd say carry on!
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I think this is a really cool approach. I've got to be honest though, from the time I saw it I've been trying to conceive a way to get a scale in play so I don't overstress the limbs. I won't have a clue how much force I'm applying with the clamp, at least for a while. Maybe I won't be able to put enough stress on the limbs to cause a problem and it's a non-issue. Guess I won't know till I try it. Can't wait.
George
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Food for thought :D thanks now I have to think >:( ;D
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I like this concept-thank you for sharing-you could possibly drill a hole that a pull scale could slip through before clamping thus giving you an idea of the weight your at as well-Hammertime.
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I am definitely trying this method! Do you work the wood any while it is clamped in place (as you would working the belly while braced) so you can see the results in real time?
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I think this is an interesting method and worth trying out, if everone allways did everything the same way we would be lucky to have candles to work by, i try to keep an open mind to new ideas, Bub
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Henry Ford said something along the lines of, "If I'd asked a committee of traditional thinkers what I should build, they would have said 'a faster horse'."
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;D
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@Shaun - I wish to re-ask a question that I think I know the answer to, but would appreciate clarification. Do you work the tiller of the bow while it is in the blocks and being stressed by the bar clamp? ...or do you remove it from clamp to remove wood and just return it to the clamp to check the progress of the tillering?
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@Shaun - I wish to re-ask a question that I think I know the answer to, but would appreciate clarification. Do you work the tiller of the bow while it is in the blocks and being stressed by the bar clamp? ...or do you remove it from clamp to remove wood and just return it to the clamp to check the progress of the tillering?
Not knowing how Shaun will answer, let me tell you my experience with tillering with the bow string. I have tillered bows while strung. It seems I always end up with a hinge in any stiff section I have worked. My guess is that I am not excercising the wood enough after removing wood. I have taken wood off until I see the tiller look "correct" and somehow I get those hinges. I just flat quit doing it. Nowadays I unstring, tiller, restring, excercise the bow 40-50 short draws without exceeding final draw weight, and check tiller again.
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I remember reading somewhere that you should never take wood off under tension. Maybe that was just the authors opinion but it makes sense to me.
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I remember reading somewhere that you should never take wood off under tension. Maybe that was just the authors opinion but it makes sense to me.
The only bow I know you take wood off the tension side would be a rattan bow. Other than that, you always tiller from the compression side. Or am I reading your post wrong, Bevan?
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Reading it wrong JW. I read somewhere to always take the string off completely when removing wood. Not to even leave it on at brace hight.
BTW, I only take rattan off on the belly, just like any other bow I make. I leave the skin as backing.
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Ok, Bevan. Understood. I hate the hassle of stringing and unstringing, but I do it because I make far fewer mistakes that way. Some shortcuts just ain't worth the trip!
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I have never worked rattan, but I think DTorges says in his video to use the skin as the belly and the inside of the split for the back - all tillering would be from the back - opposite from normal, leaving the skin intact.
Russ
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Many ways to skin a cat. I have made many rattan bows with the skin as the back. never had a failure yet.
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Many ways to skin a cat. I have made many rattan bows with the skin as the back. never had a failure yet.
Fropm what I hear you can build rattan any flipping way you want, complete with hinges so bad you would wanna cry, and they never fail. Maybe don't shoot great, but no failure!
I'd love to get a quality stick of rattan and give it a try some day.
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Will have to give it a try some day.
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I keep a rattan bow handy for letting people draw and shoot a 'self' bow. It can't be overdrawn. so no worries about draw length. It is the only 'loaner' bow I will give out.
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How heavy a bow can you get out of stick? Enough for adults to shoot the hay bales out back when they come over for drinks?
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If you get a big rattan stick, you can hit 50# no problem. I got mine from a place in California. I would always order the bigest stick they had. Usually 1.75 inch diam. or more.
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Is that Franks you refer to? That's where I get bamboo.
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No, it is Cane & Basket. They also sell bamboo clums.
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I keep a rattan bow handy for letting people draw and shoot a 'self' bow. It can't be overdrawn. so no worries about draw length. It is the only 'loaner' bow I will give out.
I always make kids understand that their bow is theirs and theirs ALONE. I explain why they should never loan it out and how to politely refuse an adult's request. This is one case where being generous isn't so good.
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I keep a rattan bow handy for letting people draw and shoot a 'self' bow. It can't be overdrawn. so no worries about draw length. It is the only 'loaner' bow I will give out.
Hey Bevan do you have a pic of that bow? I'd be interested in seeing this "un-breakable" bow.. ;D ;D it sounds like a great idea to keep one like that handy.
Jon
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I will post a pic tonight. In it's own thread. (I think we have hijaked this one completly :-[). I will also post a pic of the rattan 'blanks' I have.
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Cool thanks!