Ash "holmegård" (pics)

[Kviljo]

That's true, adb. But you really want the inner limbs to distribute the stress as evenly as possible. If not, you'll end up with a bow thats overbuilt in some places, while it is underbuilt in other places. A slow bow that will break too easily. Not something to go hunting with in the mesolithic

So yep, deerhunter, a holmegård should have normally tillered inner limbs, while the outer limbs should be a little stiffer than the wider inner part of the limbs. How much difference there should be, depens on how much difference there is in width. In theory the whole bow should be equally stressed to get the most speed and durability from the wood, like any other bow type.

[adb]

Kviljo,
NO, NO, NO.... the answer to deerhunters question is: yes. The inner limbs have normal tiller, and the outer limbs DO NOT BEND! If the outer limbs bend, their effect as levers is reduced. The whole bow is NOT equally stressed... only the inner limbs.
Sorry, but it's also a Neolithic artifact.

[Kviljo]

My litterature says they date to between 8000 bc to 5000 bc, the neolithic period in Denmark begins at 4200 bc. Which finds date from the neolithic? That said, they probably were used in the neolithic too, but I don't know of any holmegård-like finds from the neolithic.

But okay, then we agree in principle, the inner limbs should be normally tillered, while the outer limbs should at least bend less than the inner parts. But that doesn't presuppose that the outer part of the limbs should be any less stressed. If they do not bend at all, they will be overly heavy and reduce cast significantly compared to a bow with lighter tips. That's the theory.

Again, do you understand this:

Theoretically, do you agree that a bow which has even thickness along it's whole lenght, should bend like a circle, to be evenly stressed?
The answer is yes, and the reason is that the thickness decides how much the wood can bend before it breaks. More thickness and you won't be able to bend it as far before it breaks. Less thickness and you can bend it further without damaging the wood. If the thickness is the same along the whole bow, then it should also bend just the same along it's whole lenght. Like a perfect circle. That way the stress will be evenly distributed.

If you follow me on this, then you should follow me on the next point too:

To make an even-thickness bow bend like a circle, you have to taper it in width.

If not, what is the problem? Maybe I could refrase something, if it is unclear.


It's hard to say wether the original bows were made that way, or with overly heavy outer limbs. After all they're not bendable anymore, and we're left to make qualified guesses about it. But I'd credit them with the knowledge and experience to be able to make good fast durable bows.

[adb]

No, the outer limbs should not bend AT ALL. Not even a little bit. That is why they are thicker, but reduced in width, to a pin nock. It keeps them from being overly heavy. That is the whole point to a Holmegaard tiller. You could keep the outer limbs full width and thickness, but then they would be unnecessarily massive, slowing cast. When I tiller a Holmegaard, I only look at the inner limbs. They are the only ones bending. Tiller is NOT circular over the bows entire length. The rest of what you are saying about how a board bends is a red herring. It doesn't apply to this type of tiller.

Anyway, I'm not going to change your mind, so, I give up. I enjoy building these bows, and I will continue with good success. Thanks for the discussion. I guess my only other point is: be careful what you're willing to call something when you post it, you might not be accurate. Just because it looks like something you claim, doesn't necessarily make it so. No offense intended.

[CHUCKER]

What a worthwhile discussion! I am far from being a bow master, but I think you are both correct as far as your thoughs of original design intent. Last night I did some searches and viewed photos of the original bow. I would think that it must have bent, to some extent throughout the whole limb.
     That said I feel that ADB3112 design is a step forward from the original design. While it is more complex to build correctly it should produce a light Fast bow.
     Thank you both for a very informative discussion!

[deerhunter97370]

Thanks for the discusion guys I learned a lot. When I read about this bow design in TBB2 it became my favorite one. So it will be my first usable bow made from Yew. Thanks again. Joel

[Gordon]

adb,

Looking closely at the full-draw pic the bow appears to bend significantly more near the fades than the rest of the inner limb. Is the bow deflexed near the handle?

[Loki]

Good discussion chaps,i dont know which one of you is correct but i like them both!

[OldBow]

Hey, Oldbow

Full draw pic is posted.

Hmmm, sorry to be so obtuse but on what page? I see yours but not Kviljo's

[adb]

Hey, Oldbow

I posted a full draw pic on page 2 of this thread. Thanks,

adb3112

[Pat B]

The article that Hillary Greenland(sp) wrote a few years ago in PA suggests that the outter limbs do bend a bit. I guess to alleviate the stresses on the inner limb.
   It is funny, to me, how a primitive bow like the Holmgaard bows seem so complicated to us modern bowyers. I'm sure the Holmgaard people didn't think about how difficult it would be to build one...they just did it!     Pat

[Kviljo]

Nice to hear that the two monologues  () was worth the effort.

adb, check out this video:

http://kviljo.no/bue/flight.wmv

Those two "holmegårds" I shoot in the video have outer limbs that do bend. But not much. Just enough to make sure they are as light as possible.

But how on earth can it be a red herring, when you suggest that you could use two small boards (that is uniform thickness and witdth, like a board) as inner limbs and still get a good tiller. That is nonsense. It is not possible. If one understand the board-bending-thing, then you indirectly should understand that there needs to be a taper in either thickness or width, or both. If you want to distribute the stress evenly.

I have never written that this overly conventionalized ash bow of mine is even close to the holmegård artifacts. It really isn't, but the style is what we would like to call holmegård, even if it is a bit extreme. That's why it sais "holmegård", not a replication of an artifact


Oldbow, I haven't posted a full draw image yet. Hoping to post a picture of it when I have heat treated and finished it.

[Justin Snyder]

I think kviljo is right in that the amount of bending depends on the width of the outer limb.  I like the fact that his bows bend a little.  There is another significant difference in the bows you guys posted.  It appears that kviljo's bow has quite a bit of narrowed outer limb.  abd3112's bow has very little narrowed limb by comparisons. It was educational for sure.  Justin

[Kviljo]

I would say that there is only an indirect relation between width and amount of bend.
How much a section of limb should bend, depends directly on how thick it is. How much it actually is bending, depends on how thick and wide it is compared to the rest of the bow.

...which actually means that when evaluating the tiller of a bow, you only need to know the thickness. Thickness + tiller = width. In other words, if you know the tiller, and the thickness, it should be possible to calculate the width. However, it is a bit hard to do since very small variations in thickness do a lot to how much the bow should bend.

[jwillis]

Interesting discussion.  I noticed that the antiquity bow photo has the entire limb tapered in width, more like a flatbow, without a narrower outboard section.  On the other hand, the illustration below it has the inner, working limb portion tapered and narrowed outboard section.

I have to agree with kviljo on the need for tapering to make it evenly stressed for durability and performance.  Also, it seems that narrowing and thinning the outboard lever section until it (just) starts bending will allow it to be optimally lightened.  When it just starts to bend is the signal that it is as light as possible but still rigid.  If the outer levers are allowed to bend then why have them? 

Jim