Primitive Archer

Main Discussion Area => English Warbow => Topic started by: Haary84 on November 14, 2017, 12:09:06 pm

Title: Help on warbow/longbow tiller - first post! / now with pics...
Post by: Haary84 on November 14, 2017, 12:09:06 pm
Hello,

My first post!

I’m Julian and a novice bowyer from Germany. I already gathered a lot of information’s from this forum but now I need some professional advice from the pro (long)-bowyers.
I already built some flatbows from hazel and hickory with 28” DL and between 30…50# DW. But I don’t like their style... and since my childhood I fell in love with the English longbow. So I focused myself toward this design.

I recently finished another ELB, 74” NtN, 29” draw, 65#. Buffalo horn sidenocks…Hickory backed Ipe, glued with 2K epoxy. Straight glued. Flat back, slightly D rounded belly. I tried to accomplish a full compass tiller. Now I’m a bit concerned that my tiller ended up being a bit too circular…it took about 1 ½“ set that is evenly distributed over the whole length of the limbs after the first real shooting sessions.

Here shown at about 26” draw:

(https://i.imgur.com/AlpxreX.jpg)

The second one is a Hickory/Ipe/Hickory heartwood trilam, 73”NtN, 30” draw, 70#, Buffalo horn sidenocks. 2K epoxy straight glued like the other one…(my trashwoodbow…backing has a black stain/run (don’t know how it is called in English) along it, the core had some small pins and I didn’t want to use it as a belly and the belly is hickory heartwood, which shouldn’t be used as a bow wood according to some folks here and in other forums) and right as I shot it the first time it popped out of my hands and hit the floor. I could repair the damaged wood, but the prior carefully shaped buffalo horn nock broke…so the lower nock is looking a bit clumsy…you break as you make-or you break it because you are stupid… :o full compass tiller here too. Couldn’t actually shoot it until now. Only some test shots up to 30”. About 1” of set until now.

Here shown at 28” draw, the picture looks a bit strange and it tricks the eye because of the shadow at the left limb (at least I think so)…

(https://i.imgur.com/3lSbj4n.jpg)

My target is to build a warbow with over 100#, so this is why I build these bows full compass. It should be something like a training for the bows to come.  I know that they are maybe a bit overbuilt and that there are better designs. But atm this doesn’t bother me that much. Next step will be the same design (HbI) with ~80#. The trilam was only a try- maybe I will change my mind after the first real shooting sessions. Until now it shoots very well.

I need some advice if the tiller is o.k. (the warbow thing kept in mind :D) or if I should change something, before I start the next one.

Thanks for your help!




 

Title: Re: Help on warbow/longbow tiller - first post! / now with pics...
Post by: Badger on November 14, 2017, 06:33:43 pm
 The second one not too bad, maybe a little more bend in the mid and outer. The top one has some spots that are stiff and some spots that are bending a little too much but not bad.
Title: Re: Help on warbow/longbow tiller - first post! / now with pics...
Post by: Pat B on November 14, 2017, 10:28:27 pm
I agree with Badger, a little more bending mid to outer limb, top and bottom. She looks good, though.   :OK
Title: Re: Help on warbow/longbow tiller - first post! / now with pics...
Post by: Haary84 on November 15, 2017, 02:06:03 am
Thank you fellows for your reply!

Could you please give me a hint where these stiff and too much bending areas are? My tillering eye isn't that skilled yet  ::)
What do you say about the set- Is 1 1/2" ok or is it too much?
Is the circular tiller ok or should I go for a flattened elliptical tiller?

Title: Re: Help on warbow/longbow tiller - first post! / now with pics...
Post by: Del the cat on November 15, 2017, 04:31:41 am
Hi, Your tiller is near perfect  :) Your perception of it is wrong!
It is certainly not "too circular", one could argue that it should be a little more circular!
See the pic, it's a rather flat ellipse. If you bring the outers round more it will become more circular.
Del
PS. Regarding set. I place a bow on a flat floor belly down assuming the tips touch the floor, if you can get one finger between floor and grip, that's good, two fingers is ok, three is getting rather bad.
But you can probably get the set out of a self bow by strapping it flat and heat treating the belly (making sure you protect the back from heat)
Del
Title: Re: Help on warbow/longbow tiller - first post! / now with pics...
Post by: Badger on November 15, 2017, 06:31:52 am
  The top bow looks a lot better this morning than it did last night. I think it was my eyes. I still prefer a little more elliptical tiller,
Title: Re: Help on warbow/longbow tiller - first post! / now with pics...
Post by: Del the cat on November 15, 2017, 07:26:50 am
IMO the problem with the term "elliptical" is it doesn't say what shape ellipse or how far round the elliptical curve.
See pic, two ellipses and two different arcs marked (red lines and blue lines)... pretty meaningless.
To further illustrate the point. If we take the original pic of the bow, everyone seems to think the tips should come round more, well this can be illustrated with a circle or a much smaller ellipse either of which give a very similar result!
My real point is a circle is always circular whereas an ellipse has a totally unspecified shape....
Del
Title: Re: Help on warbow/longbow tiller - first post! / now with pics...
Post by: Badger on November 15, 2017, 09:39:45 am
   I have always felt the same way about the word elliptical being ambiguous. If I were to describe my preferred tiller I would say I like the middle 8 or 10" slightly stiffer and I like the last 10" of the limb barely flexing. I find if I get too circular the bows tend to feel more shocky.
Title: Re: Help on warbow/longbow tiller - first post! / now with pics...
Post by: Haary84 on November 15, 2017, 01:09:14 pm
Thank you for your replies! Nice to hear that I didn't mess it up. ;D

I already read this thing with circles and ellipses on another thread. Does it make a big difference if one uses the back and not the belly as a guide for the graphic analysis? As I did this with coreldraw I used the back and it appeared to be more a circle than an ellipse. But maybe I wasn't accurate enough ::) Is there a reason why you choose the belly for the analysis?

I got some more questions.

This is the strain/run/whatever- I don't know how its called in english. Have you ever seen something like this? It isn't a crack, but the wood appears to be different than the rest. At least it doesn't accept the boiled linseed oil as well as the rest of the wood. You know what this is and how its called? Should I avoid something like this next time?

(https://i.imgur.com/KYT3Itb.jpg)

Is boiled linseed oil a good surface treatment or is there something better out there?

Another thing- the ends of my limbs ended up beeing pretty square and not round. Is there a way to achieve a better transition between nock and limb? The conical hole is round for shure. And the limb is almost square- I couldn't manage it to combine those two shapes...Maybe I already messed the thing up at the start. First I drilled a pilot hole into the horn, then drilled with the conical shaped spade drill bit, made a fitting dowel and ground the nock as I liked on the belt sander. Then fitted the limbs to the conical shaped holes of the nocks.
I don't like the epoxy on the shoulder of the nock. But I had to use it- otherwise there would have been a big gap around the nock. Any ideas how I can improve that on my next build? I already read that buffalo horn isn't the best bet for nocks. Is it worth to use cow horn? Is antler an alternative?

(https://i.imgur.com/d6QcQI4.jpg)

Thank you very much in advance. I really appreciate your help!
Title: Re: Help on warbow/longbow tiller - first post! / now with pics...
Post by: DC on November 15, 2017, 03:53:44 pm
Make the end of the bow round and use a smaller nock?
Title: Re: Help on warbow/longbow tiller - first post! / now with pics...
Post by: Haary84 on November 16, 2017, 06:51:18 am
So it shouldn't be a problem for the backing if I round it that much? I can make the hole thing just round? But there should be a transition area between the almost square cross section and the round section, right?

Did someone already use an arrowplate (lets say 1mm thick bone or buffalo horn, not too large) on such a bend in the handle bow? Does it work or does it weaken the bow too much? Go or no go?

Title: Re: Help on warbow/longbow tiller - first post! / now with pics...
Post by: Del the cat on November 16, 2017, 07:20:51 am
I've put arrow plates on several warbows with no problem (they all flex slightly in the grip, even if you can't really see it)
Del
Title: Re: Help on warbow/longbow tiller - first post! / now with pics...
Post by: willie on November 16, 2017, 01:56:06 pm
Looking quite nice Julian, hope to see some more pics when done.

Quote
IMO the problem with the term "elliptical" is it doesn't say what shape ellipse or how far round the elliptical curve.

yes "elliptical" is a bit ambigious. I have found that if I fix the long axis of the ellipse proportional to the overall length of the bow, I can make the short axis flatter or fatter as the draw length changes. Its not perfect, but I can flatten the ellipse to match the curve at brace height,  and even the limbs quite well before even beginning to draw it further. and it is not far off at full draw.

I think that I used 1.2  times  the bow length for the last bow I tillered this way, but of course everyone likes a different curve.
I also tend to ignore fitting the curve to the last few inches by the tips
Title: Re: Help on warbow/longbow tiller - first post! / now with pics...
Post by: Del the cat on November 16, 2017, 02:53:44 pm
Make the end of the bow round and use a smaller nock?
+1
tips can almost always be smaller and the blend from rectangular to round can happen over the last 5" or so of the limb, nice and gradual.
Del
Title: Re: Help on warbow/longbow tiller - first post! / now with pics...
Post by: joachimM on November 24, 2017, 02:03:16 pm
   I have always felt the same way about the word elliptical being ambiguous. If I were to describe my preferred tiller I would say I like the middle 8 or 10" slightly stiffer and I like the last 10" of the limb barely flexing. I find if I get too circular the bows tend to feel more shocky.

Well, it's easy to define how elliptical the desired shape should be. Essentially, a circle is an ellipse with two identical (horizontal and vertical) radii. A flattened ellips has the horizontal radius longer than the vertical one.
Show us your ideal tiller profiles for ELBs, and we can easily deduce the proportions of the vertical and horizontal radius of the ellips. Say it is 1 to 1.2, we can henceforth define the ideal elliptical shape as 1/1.2, and we can also look at a tillering pic and see how much it deviates from circular, and how much from the ideal ELB (or whatever bow type that should have elliptical tiller, like holmegaards and mollegabets).

Title: Re: Help on warbow/longbow tiller - first post! / now with pics...
Post by: Del the cat on November 25, 2017, 05:44:13 am
   I have always felt the same way about the word elliptical being ambiguous. If I were to describe my preferred tiller I would say I like the middle 8 or 10" slightly stiffer and I like the last 10" of the limb barely flexing. I find if I get too circular the bows tend to feel more shocky.

Well, it's easy to define how elliptical the desired shape should be. Essentially, a circle is an ellipse with two identical (horizontal and vertical) radii. A flattened ellips has the horizontal radius longer than the vertical one.
Show us your ideal tiller profiles for ELBs, and we can easily deduce the proportions of the vertical and horizontal radius of the ellips. Say it is 1 to 1.2, we can henceforth define the ideal elliptical shape as 1/1.2, and we can also look at a tillering pic and see how much it deviates from circular, and how much from the ideal ELB (or whatever bow type that should have elliptical tiller, like holmegaards and mollegabets).
Yes it's easy to define an ellipse... BUT
That doesn't answer the question of how far round the ellipse the curve should go!  >:(
You can take your ellipse and use a section from the centre which will look almost like an arc of a circle. Or if you take a full half of the ellipse it would be ridiculously whip tillered.
(refer to the pics in my earlier post).
Del
Title: Re: Help on warbow/longbow tiller - first post! / now with pics...
Post by: joachimM on November 25, 2017, 12:07:33 pm
Granted Del.
You also need the angle of the arc each limb should cover at full draw, or the ratio of the arc covered by the bow to the circumference of the ellips.


Title: Re: Help on warbow/longbow tiller - first post! / now with pics...
Post by: willie on November 25, 2017, 07:52:20 pm
Quote
That doesn't answer the question of how far round the ellipse the curve should go
if your long axis is fixed at a given ratio to your bow length, the how far around question becomes irrelevant.
just adjust the minor axis to match the curve, no matter how far you have drawn the bow.
Title: Re: Help on warbow/longbow tiller - first post! / now with pics...
Post by: penderbender on November 25, 2017, 10:09:40 pm
I do this a lot while checking tillering pics on my phone. I just use my coffee cup and tilt it til I see what I want. Cheers- Brendan
Title: Re: Help on warbow/longbow tiller - first post! / now with pics...
Post by: Del the cat on November 26, 2017, 02:51:28 am
Quote
That doesn't answer the question of how far round the ellipse the curve should go
if your long axis is fixed at a given ratio to your bow length, the how far around question becomes irrelevant.
just adjust the minor axis to match the curve, no matter how far you have drawn the bow.
Yup, that would do it....
Just give us the numbers...
Del
Title: Re: Help on warbow/longbow tiller - first post! / now with pics...
Post by: FilipT on November 26, 2017, 03:22:50 am
For that hazel bow I am currently making I liked to use AutoCAD to trace lines and see where it bends more and less. Then I compared what the software showed to what bowyers said and it's basically the same.
Of course, con of this is that you have to have this software, but since I am studying mechanical engineering it was logically for me to use this, instead Paint for example.
Title: Re: Help on warbow/longbow tiller - first post! / now with pics...
Post by: willie on November 26, 2017, 02:06:23 pm
the number for the last bow I tillered this way was   1.2
BTW, Joachim mentioned the same number as an example when comparing the ratio of the long axis to the short axis, but for the sake of clarity, I am using this ratio to proportion the long axis of the ellipse to the bows overall length.

for instance, in the case of a 70" bow, the long axis of the ellipses I drew on my backboard were all 84", and if I want to keep the tips somewhat stiffer (for say the last six inches),  I just make the bow fit the ellipse only for the inner 58"

the 1.2 factor was chosen for a slightly stiff handled bow that can be seen here

 http://www.primitivearcher.com/smf/index.php/topic,59758.msg830731.html#msg830731

of course for a fuller compass type tiller, the ratio should be increased to get further away from the rapidly changing radius at the ends of the ellipse.

fitting a bow to an ellipse and fitting an ellipse to an already tillered bow is two different things, and I agree with Del that if you are selecting ellipses to overlay a pic of a drawn bow, there are a multiplicity of ellipses that have a chord that will match.