English longbow finished

[archangel]

Just finished my latest effort, a bamboo backed English longbow. Timber used: WA karri on the belly, hickory mid-layer and raw bamboo with buffalo horn nock tips. The bow is 72" from tip to tip and 1" across the handle. It draws smoothly for the first 18" then starts to pick up weight, around 50lb by guess. This bow originally was showing quite a bit of string follow (over 30 mm). Following Dennis' thread where he has been trying to correct faulty staves using cold reflex, I decided it was worth giving a go.

The original bow did not have bamboo backing - this was added at the same time as reflex was induced by hand-planing back the hickory lamination on the back. Once the wrapping came off the stave, it ended up 'straight as an arrow'. My first thought was disappointment, but after many shots there has been negligible loss of shape. The only concern is a number of small crystaline lines that are running diagonally across the mid-limb. These may have occurred during reflex but thankfully don't appear to have deteriorated since. A leather handle was stitched around the square handle to build up the grip. I'm delighted with the bow and will try to get some action shots at full draw soon.

[MaylandL]

Nice looking bow!

we should get together for a shoot when Hoddywell is next open for a shoot. Love to see how the new bow performs.

Have a safe and wonderful christmas and new year and all the best to you and family.

Happy shooting

[archangel]

MaylandL

That was quick mate! I have only just posted the pictures (takes me ages to get a thread done). Yep, love to have a shoot soon. My son is with us for a few months and would like to come out as well. I'll keep you up to date about some shire land that is right here in town that I am applying for use as a a traditional archery range. Merry Christmas to Anysia as well ... and your many prodigy! I still have that Ghenghis Khan DVD if you are interested.

[MaylandL]

...Yep, love to have a shoot soon. My son is with us for a few months and would like to come out as well. I'll keep you up to date about some shire land that is right here in town that I am applying for use as a a traditional archery range. Merry Christmas to Anysia as well ... and your many prodigy! I still have that Ghenghis Khan DVD if you are interested.

Sounds good to me. Lets us know and yeah, the GK vid would be good to look at.

I'll be in the process of making up a whole lot of arrows for myself and Anysia. ( http://www.ozbow.net/phpbb2/viewtopic.php?t=5967 )

Interesting thing is that the new FITA field rules require wood arrows for longbow shooters and I've ben approached as to whether I would be interested in making some arrows. If you're interested I'd like to refer some of those people to you as there may be more work that I would be able to handle.

See you in the new year

[Stickbow Hunter]

Archangel,

School is finished for the year and you now have some spare time.

Perhaps the Bamboo backing is overpowering the belly wood and causing the chrysalling?

Jeff

[archangel]

MaylandL,
I would be interested in making up some arrows. I have quite few flecthes but keep me advised especially if you are placing any orders for barred feathers etc.

Jeff,
I don't believe the bamboo backing is overpowering the belly. Karri has very high MoR/MoD (much higher than bamboo) and as far as I know it is unproven for an ELB. I believe Chris from Molinjor has played with it as a lamination in his longbows with some success. The grain is quite intricate and perhaps it does not take compression well? I have included the photo and although the lines look alarming they appear to be only on the surface.

[archangel]

School is finished for the year and you now have some spare time.

Forgot to respond to that one Jeff ... apart from bowmaking, the missus has a number of jobs around the property that I have started. My theory is to get in early and keep the little woman happy .. then I can get back to some serious bowbuilding! I want to also add the finishing touches to tiller my little horn/bamboo horsebow, then start a couple of new project bows.

[Stickbow Hunter]

My theory is to get in early and keep the little woman happy

Sounds like a wise move.

Jeff

[TomW]

Archangel

That is a beautifully elegant looking bow and I love your horn tips as well.
Small wonder you love it.

The only concern is a number of small crystaline lines that are running diagonally across the mid-limb.

Thanks for showing a picture of this. I have never seen this in a wood bow before. I still can't get my head around the idea that perhaps a stronger lamination on the back of the bow (in your case bamboo) can cause the wood on the belly of the bow some problems.

[Dennis La Varenne]

Archangel,
I directed myself to this thread after your post on my other one on cold reflexing.

It is nice to see such a success, although it is more of a Perry reflexing job than what I am doing. Notwithstanding, you have rescued a near failure to something which puts a smile on your dial. What else can one say.

With the chrysals, I have been Aschaming (my term only) them if they occur at the fret stage and this is a good preventer.

I worked it out after much laborious re-reading of Toxophilus. The technique was obviously quite well known in Ascham's day and consisted of using a pricker (needle) to put a parallel row of deep needle pricks into the wood (I do them 1-2 mm deep) on each side of the chrysal and around the end of chrysal line enclosing it in a shallow cartouche. (I notice in TBB Vol. 2, that Paul Comstock came to the same idea as well.)

This seems to relieve compression pressure on the chrysal itself and prevent worsening. I have 3 or 4 bows here suffering from this problem even though the tillering is quite good, the chrysals are not worsening, and the bows are not losing straightness (as yours appears not to be).

I surmise that this phenomenon possibly/probably arises from the highly localised compression effect of 'harder' wood on either side of softer wood along the stave which ruptures wood fibres. This is quite separate to issues of tillering.

Of course, bad tillering will also do it, but it sometimes happens when you tiller bow well, which leaves you at a bit of a loss.

You can see this hard wood/soft wood interaction when you are scraping bows and you get the corrugation effect on the belly surface of the bow. You can obviate this by using your scraper at a diagonal across the long axis of the bow or using a narrow file to ride over the humps and not into the hollows.

If you scrape along the long axis of the bow with your scraper at right angles to the long axis, you inevitably eat into the softer hollows to create the corrugations where the frets, then chrysals begin to appear.

Years ago, I did notice this chrysalling effect occurred almost every time when I was trying to get a couple of staves from a piece of Qld Spotted Gum floorboard. It was highly figured with a beautiful rippled/fiddleback grain effect. The lighter 'lines' of the ripples where the cut grain ends showed at the surface were quite hard, but the darker areas between them were much softer. It is inside these darker areas which took the frets where chrysals formed. To look at, your pictures remind me a lot of the cut surface of Spotted Gum in texture and colour, and it may a similar wavy grain.

This kind of chrysalling is possibly a natural compression self-relieving process in wood which has nothing to do with tillering. If there are some wood techs on the site, they will probably be able to explain better, but that is something I have observed with a small few kinds of wood now, and it may apply to other woods.

Anyway, try Aschaming your frets/chrysals. It will do no harm. Just fill them with wood finish to keep moisture out of course.

Dennis La Varenne

PS: May I offer one thing on ELBs?? Don't put rigid handles on them. At most, raise them from the tips to a highest point at mid-bow, but allow them to bend through the handle. It destresses them a lot without sacrificing cast, believe it or not.

I make mine with a parallel width centre section of around 1/4 of the full length of the bow and tapering in two stages to the horns. At 7/8 of the way from middle to horn, I make them 3/4 of the mid-bow width, then tapering to completely round to fit the horn. This keeps the tips light.

The thickness is a straight-line taper from the parallel centre section to the horns. This gives the bow good lateral stability.

I have attached a schematic of my design which seems to approximate the Mary Rose bows. The backs of this design are well-cambered and NOT flat so the back-belly ratio is reasonably balanced.

The 30mm cross section diagram can be linearly scaled for lighter or heavier bows and keep the same proportions. The amount of scaling will depend upon the density of the materials you are using. A 30mm wide Karri bow would be heroic indeed.

[archangel]

Dennis,

Your remarks about the cause of crystaline problems are both perceptive and accurate. All of the things you have described in this case appear to be definite contributors.

Years ago, I did notice this chrysalling effect occurred almost every time when I was trying to get a couple of staves from a piece of Qld Spotted Gum floorboard. It was highly figured with a beautiful rippled/fiddleback grain effect. The lighter 'lines' of the ripples where the cut grain ends showed at the surface were quite hard, but the darker areas between them were much softer. It is inside these darker areas which took the frets where chrysals formed. To look at, your pictures remind me a lot of the cut surface of Spotted Gum in texture and colour, and it may a similar wavy grain.

. The affected part of the stave has exactly this rippled grain effect that you mention. Although karri has stringy splinters running down the timber, every now and then intricate whirls are formed.

If you scrape along the long axis of the bow with your scraper at right angles to the long axis, you inevitably eat into the softer hollows to create the corrugations where the frets, then chrysals begin to appear.

. I did use a cabinet scraper and can see how this could attribute to the problem.
However I think you have hit on the problem when you suggested

May I offer one thing on ELBs?? Don't put rigid handles on them. At most, raise them from the tips to a highest point at mid-bow, but allow them to bend through the handle. It de-stresses them a lot without sacrificing cast, believe it or not.

. The stave originally started out 30mm square as I planned to make a self-bow. However it was so powerful I would have needed a windlass to draw it back. I decided to plane it right down to pretty well match the 25mm dimensions you have described. I think it was Jeff who noticed that the mid-limbs were bending too much at the end of the handle section and this are the very spots where crystalling has occurred.

Regarding your recommended dimensions, I checked all the other areas and apart from the fairly rigid mid-section, measurements are virtually indentical. When I was adding the bamboo backing, the circular ends of the stave to receive buffalo nocks were 1/2" diameter. The diagrams you have provided will help greatly when I build my next ELB - thanks again, your expertise has encouraged me to persist with karri laminations as it seems be a promising timber.

[Lochmoy]

Great job. Wished you lived in Victoria.

[TomW]

For Dennis
The diagram showing the cross sections of the ELB is really interesting.

Are you able to relate how this particular cross section came about, because it is hardly intuitive?

I'm really curious as to how the early bowyers decided on a curved back and such a deep belly.

[Dennis La Varenne]

Tom,

My schematic is really my own reading of the shape of the Mary Rose bows (on average) from pictures I have seen of them. There is a certain amount of interpretation in the actual width profile, but in reality, I would not be in the least surprised if nearly every contractor in Tudor times (and earlier) had a slightly different take on the basic design. About one quarter of the Mary Rose bows were deep rectangular with rounded corners. The backs were as they came from the log, so there would have been a great variation in camber.

So far as I can ascertain from Hardy (Longbow, 1992), the sapwood was not interfered with apart from well rounding of the sides of the sap and blending into the belly - the so-called 'Mary Rose sharp edge' as Roy King's notes in Hardy's book (pp.220 -221, 1992 edition) indicate.

Roy King was warranted to build a Mary Rose replica from a good stave supplied by Don Adams of Oregon. His notes in 'Longbow' say -

. . . 'Sides worked down dead square to back, to what should be finished width, leaving just a little extra at the tips . . . Slightly convex taper . . . '

'Back generously radiused over full width, dropping a little extra at the edges. Then there appears as if by magic the Mary Rose sharp edge . . . '

Going back to page 214 of the same edition, there are some cross sections of two very different bows, the one is nearly circular with the slightest flattening of the back out to about mid limb, and the other is clearly a bow which maintains much of its original rectangular cross section, radiused as above and in my diagram but with very flat sidewalls.

Both these bows have a very deep stack, in the case of the 'round' bow at something very nearly 95% of width, and the 'rectangular' one at 85%.

As it turns out also, my design is very similar to Pip Bickerstaffe's bows, except that he got his design ideas from the 'horse's mouth'. Mine were just extrapolating dimensions from available drawings.

When you think about it, the slightly convex width taper is a considerable aid to lateral stability in an essentially skinny bow. You keep it as wide as you can for as long as you can consistent with intended draw weight. The stack comes from how much wood you need to leave to get the draw weight you want because that is all you have to work with, and the length destresses the wood without sacrificing cast. The overall design allows you to get the greatest number of bows from a given log, so the design is a bit more practically intuitive than might at first seem.

All of the problems of making stable skinny bows would have been well known for centuries or even millennia. The English Longbow is the very same design as that of the Iceman from 5000 years BPE.

Like most things in nature, a similar problem usually results in a similar solution. I fixed on an 80+% stack because that was consistent with known examples of the design, and the width taper also consistent with the design. I broke up the length into an 'easily digestible' set of proportions rather than defined lengths so that a bow of any length could be made to proportion. The cross section figure I drew enables a linear scale up or down to be done consistent with an intended draw weight. My concession to Roy King's slightly convex taper' is the 3/4 base width at 1/8 from the tip.

My rule of thumb advice in working out a draw weight is to buy a board and weight it. Make a bow of a specific dimension from it and draw-weigh it when finished. That bow becomes your 'standard' bow from your 'standard board'. Providing the length remains the same, a proportionally lighter bow can be made with a cross section proportionally smaller as a percentage of your 'standard' bow.

If you buy a board which is heavier or lighter than your standard board, then bows made from it will scale up or down in cross section by a similar proportion.

However, changing lengths will require an additional set of sums on piking.

Clearly, this is not a 100% thing, but it should get you into a ball park range for quick and high production levels if you ever decide to get into that. It will also let you make a more pre-planned bow with a more guaranteed end result in terms of draw weight.

Just one final thing on tillering this kind of bow, I would still use an in-line tiller placed dead centre of the stave. These bows don't have handles and the tiller should be ZERO - both limbs having mirror bends.

They are shot by holding them where it balances on the hand at draw and nocking the arrow on top of the hand at 90 degrees (by eyeball) to the bowstring. The offset tiller is only necessary with bows having a predetermined and constant grip position.

The Mary Rose bows had arrow pass nicks in the sides. There were often several of different kinds. It is tempting to speculate that in military use, the archer took the standard issue bow he was given from the supply waggon, braced it to his liking and found a his own 'sweet spot' which he marked. Military bows were made to a recipe by necessity and the archers had to adapt to that recipe. A zero tiller would fit all.

Dennis La Varenne

[TomW]

Dennis

Thank you very much for that information. When I get around to trying to make my first self ELB I will use it.

I've always had this feeling that making a self bow was far more complicated than making a laminated bow and you have confirmed that for me. It truly is an art.

You clearly have a very wide and deep knowledge of the subject and I tip my lid to you for your expertise and for taking the time and trouble to explain it to someone (me) who is, for all intents and purposes, an empty vessel in terms of knowledge and expertise.

Many thanks again. I really appreciate it

Regards

Tom

[Dennis La Varenne]

Archangel,

Here are pics of 'my' Aschaming technique. These are quite bad 'pinches' as Ascham called them. They are on a little Holmegaard I made a while ago before I had the unique tillering methods required by this design worked out. It is made from Victorian Red Ironbark of the tricarpa sub-species. Interestingly, this little 64 inch bow has stayed dead straight, and the pinches don't seem to be worsening.

It might give you a better idea of the technique than a written explanation.

Tom,

Returning to your post on the 25th above with regard to a backing material overpowering the belly material of a bow, you can perhaps grasp the idea the following way.

Take a lamination of wood - 2m long x 3mm thick x 40mm wide. The lengths of the upper surface and the lower surfaces are both 2m long. If you bend this lamination in a circle so each end abuts the other, you have a circle. However, the outer surface of this circle is longer than the inner surface in view of one being the inside of the circle.

To achieve this, the outer surface of the lamination had to stretch and the inner surface had to compress, each by equal amounts. That is what happens with any wood.

However, if one were to adhere a strip of utterly stretch resistant material to the outer surface of the lamination and then try to abut the ends, the inner surface would need to compress considerably more in order to achieve this.

How much the inner surface needs to compress will depend on the stretch resistance of the outer surface (backing) material.

Normally the wood in self bows is relatively in balance between stretch resistance on the outside curve and compression resistance on the inside curve. However, if one adheres a stretch resistant material (such as a band of steel) which is far greater than the original wood, then the amount of compressing needed to be achieved by the original wood may be so great that it exceeds the natural elastic limits of that wood to the point that it stays permanently bent and even to the point of fracturing (rupturing).

When this kind of permanent bend results in a bow, it is said to have taken a set or to have "x" amount of string follow.

If we intend to back a bow with a 'foreign' material, we need to take cognizance of the stretch resistance of the backing material to make sure that it is not significantly more stretch resistant than the material which we intend to 'back' or 'reinforce'.

If it is much stronger, then it is almost inevitable that the bow will take a set. And so we say that the backing material has overpowered the belly material.

I will stick my neck out at this stage and say that I consider that it is mechanically unsound to back a bow with an excessively strong material even when building a reflexed bow.

With the single exception of sinew backing, no other material physically pulls a bow back into reflex after shooting including bamboo. Sinew is very different in behaviour to other materials in that it is NOT very tension resistant, but highly elastic. In other words, it stretches easily, and so it puts less compression load on the belly wood, but also returns better to its original shape. All the other backing materials we use are often highly tension resistant (they don't stretch easily), but not very elastic (they don't return to their original shape well once stretched).

Trapezoiding a bow to the back (making the back narrower than the belly) or thinning it when using bamboo is another way of demonstrating that bamboo is still too strong for the belly wood because the amount being used must be reduced in surface area and/or thickness in order to bring the stretching and compression forces on the back and belly surfaces of a bow into balance.

If I were to use bamboo as a backing, I would mate it with a wood whose natural stretch (tension) resistance was similar to that of bamboo.

Otherwise, I cannot see any particular benefit in not using a self-backing such as Spotted Gum on Spotted Gum, Hickory on Hickory, Red Ironbark on Red Ironbark, etc. when making a reflexed bow, or in combination with another wood with similar mechanical properties such as Hickory on Spotted Gum or Red Ironbark or the reverse.


Dennis La Varenne

[Len]

Dennis, I'm sure a lot of beginner bowyers are very glad you're willing to share you're knowlage of bow making, thankyou.
On you're comment on bows bending through the handle and how it won't rob cast, evidence seems to suggest with heavy arrows it actually adds to the bows performance. Mind you I'm talking historical evidence not personal as I havn't yet had a chance to test it out.

[Dennis La Varenne]

Len,
I am not prepared to go so far as to state categorically that a flexible handle bow has better cast, but from my personal experience of making both rigid and flexible handle ELBs, the only differences I could find could just as easily be attributable to better quality wood in one bow than the other or even what side of bed I got out of that day.

Pip Bickerstaffe seems to think that flexible handle bows have slightly more cast (but more handshock) than rigid handle bows. He has specialised in these bows for many years and I would not readily gainsay him.

However, I have not found them to have any noticeable handshock. My belief that keeping that outer 1/8 of the limb as fine as practicable is a significant factor. They just feel a bit odd to draw when you have been using rigid handle bows. When you feel that bit of flex, it can be a little offputting at the start until you get used to it.

Dennis La Varenne

[Len]

Dennis, just about all of my bows bend througth the handle as they are medieval style bows not victorian butt bows and I guess I don't know shooting any different . On my last bow which I've made over the break, I've made it a little stiffer through the centre as its been made just for target work and it does seem to be a bit easier to shoot accurately though it could also be because its only 50lb or maybe mind over matter
Talking to the guys who shoot the heavy warbows, they seem to think that a bow that 'comes round full compass' pushes a heavy arrow better as the whole bow is working and transmitts more power to the arrow.

[Dennis La Varenne]

Len,

We will have to be a bit circumspect here because we are hijacking Archangel's thread away from his newly finished bow a bit.

Again, I am a bit bemused (not amused) about claims that 'bend-in-the-handle' bows cast heavier arrows better than rigid handle bows, and I would want to see some good evidence that this is true. The only claim I would make for flexible handle bows is that the bending loads on the limbs are reduced by spreading it over a longer limb length.

Hypothetically, if mass x acceleration = energy, then more moving mass in the form of more bending limb yielding more energy should overcome the inertia of a heavy arrow better, but I doubt if it is definitive. It would take a lot of testing of a lot of bows and good accurate observers to measure the differences.

With your new rigid handle bow of 50lbs, I would be more inclined to attribute your improved accuracy to ease of shooting rather than the rigid handle. Make a 'full compass' bow of 50 lbs and see if you can shoot it as well. You have been shooting your 80lber at 28" for a while. A 50lber would be a kids' bow by comparison and I would be very surprised if you couldn't shoot it better.

Dennis La Varenne

[Dennis La Varenne]

Tom (through Archangel's chairmanship of course),

Here is my take on bending theory as it applies to bows and follows on my post earlier today. I hope this expands what I have been saying and relates to the how and why of material failure on the backs and bellies of bows which happened to Archangel's bow - the subject of this thread.

Dennis La Varenne