Primitive Archer
Main Discussion Area => English Warbow => Topic started by: dobson on May 05, 2013, 11:12:15 am
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Hey guys I could do with some help tillering my new bow. In the past I have always, always made a hash of tillering, especially with a long string so hopefully with a few second opinions I hope not to rush into any mistakes!
So far its belly has been roughed out into a D, the back has been rounded on the edges and it bends slightly in floor tiller. I am aiming for anything between 45- 60 pounds at 28 inches, The bow measures just above 72 inches. This is my very first try with my new tiller tree:
Bow at tension (6 inches)
(http://img507.imageshack.us/img507/2226/ashbackedelmfirsttiller.jpg) (http://imageshack.us/photo/my-images/507/ashbackedelmfirsttiller.jpg/)
At 10 inches (4 Inches if you take away the slack)
(http://img341.imageshack.us/img341/475/ashbackedelmlongstring4.jpg) (http://imageshack.us/photo/my-images/341/ashbackedelmlongstring4.jpg/)
To me the left limb (bottom) is bending far more than the right but as said any advice is more than welcome
Cheers
Liam
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Have you rounded off the back of the stave yet? If not... that should be the first thing you do. Next, continue to floor tiller, and get rid of the long string! A long string to me is one that is the same length as the bow.
Also, you haven't told us anything about how long your stave is, and what you're trying to end up with. You never want to draw your stave past final length and weight. Are you using some sort of scale, or just guessing?
For me, I get the middle of the bow moving first, and then bring the tips around last. If you do it the other way, you might end up whip tillered, with a lot of set.
In your pics, your stave is not really bending at all.
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This is what my last warbow looked like on the tiller... maple backed yew, 90#@30", 76" ntn, bottom limb on the left.
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Thanks for the reply and pictures! Yes the back has been rounded, I have edited my original post to avoid confusion but the bow measures just over 72 inches I'm aiming as high as I'm trying to keep the draw weight as high as I can get but ill be happy with 45 - 60 pounds at 28 inches.
at the 4 inches of draw the bow was pulling 20 pounds, the scale is not in the picture.
The string is fairly long because of the block in the tillering tree, If I had a shorter string it would be under tension before I used the pulley to pull it down.
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Your string length is fine at this stage, but don't use it too long. When you get six inches of tip deflection (not draw length) you should switch to a short(er) string.
Although the bow is only pulled a few inches in that pic, you can still see clear weak spot (future hinge) in that left limb. About 12 to 14 inches from the tip. I think I can even see a thin spot there. Run your fingers along the length of the bow and feel the thickness taper. Are there any thick or thin spots? A caliper will tell you for sure and tells you if the right limb is matched in thickness. Remove wood from the entire length of the bow, except for that hingey area. Only pull it further when you can no longer see that hinge.
By the way, you posted this in the 'warbow' section, whilst this bow does not look like one. You desired draw weight is also too low to qualify as a true warbow. You would you gotten more views and replies if you posted this topic in the regular bows section. Perhaps an admin/mod can move it.
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The key thing is to decide on your target draw weight!
ease off the right limb a tad so they both start to flex and pull it back to about 50% of your target weight, if it's still bending evenly pull it to 90% target weight, watchin it as you do it. See how far it pulls back, and then start adjusting the tiller.
If you keep pulling it to 20# you'll just end up with a 20# bow!!!
Better to put some weight on early when it won't break as it's still pretty stiff and you'll only get a small deflection.
They don't break early... they wait until you've nearly finished... >:(
BTW I don't round off the corners until it's about half way tillered, some adjustment of the belly can help prevent twist or sideways bend... can't do it if you've already removed the wood. Prob not as important on backed or laminated bows... just sayin'
Del
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You need to shorten the block holding the bow on the tiller tree. It's getting in the way of you putting your bow up on the tiller with a short brace. Look at the pic of my tiller tree setup.
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Thanks again guys some really helpful advice in there!
Dark soul I agree there does appear to be a hinge there ill make sure I don't touch that area! By shorter string do you mean I should brace the bow or just use a very short long string (as in the same length of the bow)?
Yes the weight ill be aiming for (decided on 60 pounds that way if it ends up being under I wont be disappointed) is far below Warbow weights but I thought this section would be the best place for advice on English longbows that bend "full compass" but in future ill post in the regular bows section.
Del ill make sure to try that out, should i have the bow braced at that point of can I try that with the long string? Cheers for the advice on corners ill keep that in mind if i ever try to make a self bow!
Ill also alter my tillering setup so i can get a shorter string on there
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By shorter string do you mean I should brace the bow or just use a very short long string (as in the same length of the bow)?
I would guess he means shorter longstring, as in the same length nock to nock as the bow. I even use a little shorter if I can, so much that you have to bend the stave and stretch the tiller string just a tiny little bit to get it on there. Just a tiny bit though, so when it is on there the string is flat against the belly with zero brace height, but taut. My favorite cord material for tiller strings so far is 550 paracord. It has very little stretch, is strong enough for the heaviest bows, but is small diameter enough to fit in small nocks. Also, you can retie just normal knots in it over and over again without any harm to the cord, where normal bowstring material don't work like that. So you can use one longer string to tiller 78" bows to 40" bows.
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Ok so I had a go at trying to tiller the bow with a cabinet scraper, as I'm being cautious I only removed small amounts from the entire bow apart from the 12 inches from the bottom (left) limb tip. I also did a few more passes on the entire right (top) limb as it seems too stiff. However I am unsure how to proceed
(http://img23.imageshack.us/img23/2931/78926878.jpg) (http://imageshack.us/photo/my-images/23/78926878.jpg/)
The long string is as short as I can get it without bracing the bow, in the picture the bow is pulling about 25- 30 pounds
In my opinion the left limb looks like still not bending towards the handle and i cant tell if the bend is a hinge or that is correct. The right limb looks like it needs more work on it but as I said I'm being cautious at the moment .
Where should I be focusing?
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Your bow is not really bending anywhere yet! If you want 60#, pull it a bit more, and see where it wants to bend. The left limb is moving a tiny bit, but the right is still poker straight.
You're being too cautious! Give it a tug and make it bend! Don't worry, it's not going to break.
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This is what my last warbow looked like on the tiller... maple backed yew, 90#@30", 76" ntn, bottom limb on the left.
Hey abd, what scale do you use? Can you find it online?
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I bought my scale at a local butcher supply wholesaler. I know you can get them way cheaper on eBay. Search there for a 'hanging scale.' Talk to Cameroo, that's where he got his.
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Ok so I had a go at trying to tiller the bow with a cabinet scraper, as I'm being cautious I only removed small amounts from the entire bow apart from the 12 inches from the bottom (left) limb tip. I also did a few more passes on the entire right (top) limb as it seems too stiff. However I am unsure how to proceed
(http://img23.imageshack.us/img23/2931/78926878.jpg) (http://imageshack.us/photo/my-images/23/78926878.jpg/)
The long string is as short as I can get it without bracing the bow, in the picture the bow is pulling about 25- 30 pounds
In my opinion the left limb looks like still not bending towards the handle and i cant tell if the bend is a hinge or that is correct. The right limb looks like it needs more work on it but as I said I'm being cautious at the moment .
Where should I be focusing?
Removed any more wood yet?
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Your bow is not really bending anywhere yet! If you want 60#, pull it a bit more, and see where it wants to bend. The left limb is moving a tiny bit, but the right is still poker straight.
You're being too cautious! Give it a tug and make it bend! Don't worry, it's not going to break.
I respectfully disagree. While this bow is indeed hardly bending yet, there is absolutely no need to pull it any further. In this picture, you can already see that weak area in the left limb, even though it is only pulled a few inches and the draw weight is still low. You should never pull a bow further than required to spot a flaw in the tiller that needs to be corrected. The weak spot is still visible, so that needs to be corrected before he should pull it any further. If you do pull it at this point, you'll most likely introduce set.
Dobson, you are doing fine. I can see the tiller is improving, but you've obviously just started. Scrape the inner half of the left limb, and the entire right limb. A scraper, combined with the occasional 40 or 60 grit sandpaper to remove scatter marks, is a good tool for that.
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Do not fear Dark soul for that is exactly what I have done, not managed to get much time on the bow since the weekend but I as you said I have not pulled the bow any further because I'm worried of worsening that hinge, while this isn't my very first bow its my first for a long time, on all of my previous bows there's always a weak spot that's been over-strained and pronounced where I got impatient and frustrated with the tiller that explains why Ive been going as slowly as I can.
So far I scribble pencil across the area that I want to remove then scrape it off with a cabinet scraper try it on the tiller this is much more slow going than what i used to do but so far I haven't managed to ruin anything.
I have done some more work on the bow but it was more focused on getting the right limb bending ill go back to taking more wood off the middle left as well.
Just for future reference if I want to get rid of a hinge can i remove wood before and after a hinge (in this case obviously I need to shave down the middle left but what about the extreme tips?)
For your pleasure here is the last bows I made, I'm not sure if its obvious in the tiller but in the lower right limb there is a weak spot (I know the bottom nock is missing, I pressed the bow into service to test my new tiller)
(http://img845.imageshack.us/img845/1694/imag0190gv.jpg) (http://imageshack.us/photo/my-images/845/imag0190gv.jpg/)
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Other than the right tip being a bit stiff, I can't find a whole lot wrong with your tiller on that bow.
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Okay its been a while but i've finally had a free weekend to continue scraping away really need a hand to see whats going on here! :
Bow is still on a long string (but as tight as possible!) pulling about 35#
(http://img826.imageshack.us/img826/9789/imag0212kt.jpg) (http://imageshack.us/photo/my-images/826/imag0212kt.jpg/)
Uploaded with ImageShack.us (http://imageshack.us)
To me It looks like the lower quarter of the left limb needs work and I need to start to get the center bending.
Any advice would be welcome! Should I start to try and get it at a low brace now or do I still need to do some work on the long string?
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It's still looking a bit hingy on the left mid/outer limb. The right looks better.
One tip for you is to draw a vertical line down the center of your tillering board. In line with where your tillering scales hook will sit on the string. If one limb is stiff then the hook will 'creep' over to the side of the strong limb as you pull down on your rope.
Remember that the long string will give you a false impression of how the tips are bending. It makes them look stiffer than they are. If you remove wood near the tips to 'bring them round' a bit then when you brace it they will be bending too much.
I strongly recommend you google 'tillering gizmo' and make one. It will greatly aid you on this bow. The bend on this bow should be mildly elliptical eg. bending fractionally more and more as you move away from the handle.
So your next step is to get it bending evenly at this weight and as soon as possible pull it to 60 pounds. With these bows I get it bending to about 20 inches with long string at full draw weight and then brace it. For you i'd stop with the long string when it's pulling 60 @ 16. Then brace it very low and continue.
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Uuuhhh... Ash backed elm? That is a contradiction if I ever heard one.
Still need to work that right limb a little more. Maybe a little off the left INNER limb... but don't go too far.