English Longbow Help (with image)

[markc324]

Hi,

I'm new to archery and would love to learn more from all you good folks! I'm trying my hands on making a bow since I know how to build stuffs (self-taught mostly..) and am confident with my craftsmanship. The bow I am making is jatoba (brazilian cherry) backed with maple to sort of mimic the yew wood. I think I have the whole thing up to this point in pretty good, if not excellent, shape...I've rounded the belly, bevelled the edge of the backing, attached and grooved the horn nocks. Now for the scary part - tillering...as much as I love the way things turn out thus far, but with bad tiller, all these milestones will all come to the unfortunate failure. Please refer to the images attached to this post. I've added one original and one with my own diagram drawn to it. according to the diagram, i can see that the top limb (right) is bending a tiny bit more then bottom limb (left), which is ok as long as it is within ⅛" - ¼" (i've read this somewhere. please correct me if I am wrong on this). Please provide your input and thoughts on the current tiller. Feel free to add your own diagram to the original image for analysis, and also, much appreciated if you guys can give me some pointers on what to do next.

I should also mentioned that the bow is having a low brace right now, 5" to be exact, and has not bent past 6-7 inches so far. at this point, is it safe to brace to 6.5" brace height?

[markc324]

can you guy see the images attached? it shows up on my computer, but not my phone nor my wife's computer. I wonder if you guys are experiencing the same thing.

[WillS]

Your bow has far too much bend in the middle, and none anywhere else.

At such an early stage, you want the midlimbs to be doing most of the work, as the middle only starts bending towards the very end of the draw.  The further you pull a bow, the more the middle will try and bend so if you were to take your bow as it is now and draw it to 30", you'd see a massive hinge smack in the middle, and stiff limbs everywhere else.

You can keep it at the current brace height if you want, but work only on the mid-limb to tip section on both sides.  You're going to lose a lot of draw weight and take some set but that's how you learn!

What I would do personally is unbrace, reduce the limbs and then brace it again, and keep repeating until the brace shape shows an even bend in the midlimbs and much, much less bend in the middle.  Then start drawing it on the tiller and make sure the middle doesn't do any more bending until at least 20" if not more.

[cadet]

What 'e said: I'm no expert, but that's not bending all over like it should, it's all in the middle; mid limbs and tips need to start bearing some working load.

[Badger]

  Looks like you might have the beginnings of a hinge right where it sits at the door jam.

[Del the cat]

Dunno if I'm not understanding but it seems you are trying to make a bow first and then pull it.
It doesn't work like that! (others may tell you different)
You have to work with a target draw weight and draw length. Pull it to your target draw weight as long as there isn't a problem like a weak point or it is bending unevenly), you then look at the draw length, if it's not drawing far enough you then remove wood from the belly and try again.
So typically you'd get results like this... assuming you want say 100# draw weight at 32"
You pull 100# and it comes back 12" you remove wood, to adjust the tiller and try again, it's then
100# at 13" you remove a little more, improving the tiller.
100# at 14", you increase the brace height to a full 6" and try again.
100# at 14" still, you take off more wood...
and so on until you get to 100# at 26", you then start really narrowing the tips fitting nocks and bringing the tips round the last little bit.
100 at 30"... you quit there, as it will settle down to 100 at 32" once it has been shot in.
It is doubtless possible to build a bow by numbers (especially a laminate) and just take it to full draw... it doesn't mean it is a good idea.

With a warbow it hard to get to initial brace, if it is easy, you will probably find you end up with a 70# bow not 100#
Del
PS. Not sure if this post from my blog will help, it should at least provoke some thought.
http://bowyersdiary.blogspot.co.uk/2013/12/yew-stick-bow-and-draw-weight-to-brace.html

[willie]

as Del has implied, doing the finish work before seeing if the stave will become a bow, is a way to set your self up for disappointment if all does not go well.
Seeing the correct bend at 6" is not a skill that comes easy for many, and I certainly ruined a few pieces of wood while learning.
One possibility you might consider, would be to rip a 1/4" slat and side tiller it so that it has the final shape you desire at full draw.  a true arc of a circle at full draw might be a good place to start for a  warbow. comparing curves of your model to the jatoba laminate, at lesser draw lengths, will give you some reference to work from.

[meanewood]

Don't panic, your only at brace height and there is plenty of time to get the bow bending in a more even way!

What normally happens is that by floor tillering or using a long string, you are able to check the bend before reaching brace height.
You can't always rely on the bow being worked down to what you think is a correct taper and then bringing it to brace.

I don't think the tiller shape you have at the moment is a problem as long as you don't have any crystaling.

Your next step is to mark the areas that need to start bending more and reduce them slowly in order to get the brace height tiller to be a bit more even. However, don't bend it beyond 7-8 inches in-order to achieve that.

The main lesson to learn here is tillering starts as soon as the stave is flexed!

[markc324]

wow, thanks for all the good inputs! i've actually absorbed and digested a good amount of it before continuing the work session this morning.

one thing i want to mention, though, it that I didn't actually "made" a bow first and then tiller it. the wood is actually very rough. I just rounded the belly and the edges of the back so it will start to bend, but it needs a lot more shaping here and there. as for the horn nock. I admit it really isn't the stage where they should be added, but they are only glued on (with Del's 6" mark on masking tape trick i learnt from youtube!) and more shaping is required. Sorry if I scared any pros out there and made you think i backtracked on this project!!

here is the image as of the end of the tillering (or more of a workout for me)...

currently it is at 70# @ 30". my target is 70# at 32" (i am 6'2"). I took it nice and slow; giving it 30-40 repetitions of pull before I move down to the next inch of draw, and then repeat the 30-40 rep exercise.
at current state, it is not showing any chryshal mark or cracks. Bow shows 1.5" of set/string follow but relaxes to 1.25". How does that look for a 74" NtN bow with such draw weight? Both limbs are bending very equally. I divided each limb to ⅓'s and measure the distant of belly to string and one side matches with the other dead on, no + or -!

To my inexperience eyes, i think it is a good outcome for the first bow, but I believe it is by no means perfect and I still have much to learn. I can see tiny gaps between the limb and the blue circle i drew. I will refine that as I finish it up in the next couple of days (definitely taking my time on this project).

please see the images and share your comments and suggestions of what to do from here. Much appreciated!

[willie]

nice smooth bend, I am watching with interest to see what advice you get from the pros about the last two inches.

Have you shot it much at 30"? I might be tempted to shoot it in some, before final tillering/sanding.

[markc324]

thanks, definitely happy with where it's headed!

if what I've leant on my own search on internet is true. the last 2" doesn't really bend, do they? I remember seeing videos about sanding through the sap wood growth ring of yew around that area for his own reason, and the bowyer mentioned there's practically no bend there; but he also mentioned that he knows what he's doing and should never go through growth rings anywhere else. Im anxious to see what the pros will comment on that, too.

I haven't shot it in yet; mainly because my arms are tired after a whole day of workout. I'll be training the bow to shoot either tomorrow or the day after.

[willie]

there is a lot I have to learn about warbows, let alone yew, so I can't comment on the "no bend" thing, but jatoba could be entirely different. My thought was to shoot it some and inspect closely for chrysals and tiller change for a while, perhaps have someone take a photo of the bow drawn in the hand to compare with your photo on the tree.

[markc324]

look what i just found out!

the previous image with the blue "circle" was and ellipse. I accidentally compressed it up-down direction without noticing and i just noticed it now. I changed it back to a circle and the last two inches mentioned by Willie all of the sudden appears to be pretty close to the arc!

[willie]

i see now that you are referring to the tips as the last 2", and yes, they really do not bend that much.

I was speaking to the fact that your tillering stands at 70#@ 30", leaving some small reductions undone to make weight at your design pull of 32".

[meanewood]

Willie makes a good point about shooting the bow in a bit before sanding and finishing.

I think Asham makes reference to shooting the bow in and then returning it to the Bowyer to 'Pike', which may mean putting on the horn nocks.

Anyway, your bow is looking great!