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    Prod bindings

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    mac
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    Prod bindings

    Post by mac on Wed Jan 04, 2012 9:31 am

    Over on this thread, http://thearbalistguild.forumotion.com/t525p15-leather-braiding-to-bind-on-stirrup#4593 there was a call for information on how prods are bound into the tiller.

    Here is my first series of instructional sketches. It shows what might be described as a "plain and simple" binding. There is nothing here that most of you don't know already; but it should serve as a sort of jumping of point for the discussion of more complicated bindings.

    Mac


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    Re: Prod bindings

    Post by stoneagebowyer on Wed Jan 04, 2012 10:11 am

    That makes perfect sense. Thank you!

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    Re: Prod bindings

    Post by Lightly on Wed Jan 04, 2012 10:39 am

    NICE! And thanks! Again...
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    Re: Prod bindings

    Post by Ivo on Thu Jan 05, 2012 10:16 am

    Hi guys,

    I have a quick question and I'm sure I'm not the first to ask this, since this method of tying in the prod has been *lightly* discussed already.

    - At the end of the loop-de-loop procedure Smile , the final step is to secure loose ends...what would be the recommended knot or other method of securing the ends?

    Thanks,

    Ivo




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    Re: Prod bindings

    Post by mac on Thu Jan 05, 2012 10:47 am

    Ivo,

    In the past, I have tucked the ends through the bundle of parallel cords between the figure 8s and the bow, but that's difficult, and never looks right. I have also brought the end back under the last turn of the figure8s, but I haven't seen anything like that in surviving bindings.

    I depicted the end simply tucked in between the bindings and the tiller, because I have not found evidence for anything fancier. The very end of the cord is not under any real tension, and the bindings are typically covered with some sort of glue.

    When bindings get loose, it is either because the linen has stretched, or the wood has collapsed. It is never a case of the figure 8s or the frappings slipping. All in all, I think it will stay just fine without any sort of knot.

    Mac
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    Re: Prod bindings

    Post by stoneagebowyer on Thu Jan 05, 2012 2:51 pm

    Mac, what do you most recommend for binding material? I have always loved linen, but if you think another type of material is both authentic and servicable, please give us your suggestions.

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    Re: Prod bindings

    Post by mac on Thu Jan 05, 2012 3:06 pm

    Here is the next installment.

    This is a reconstruction of the binding of the Gothic crossbow in Köln (inv.-Nr. W 1109). The current binding of this bow does not make correct use of the holes in the "nose" and "chin" of the tiller. I am using the binding of the wallarmbrust in the Schweizerischen Landesmuseum (Inv.-Nr. AG 2570 as a model.

    Images II through VII show the method of dealing with the holes in the "nose" and "chin" of the tiller. It is important to note how the loops from the nose and chin holes are pulled back by aditional loops from the main binding hole.

    Image VIII shows the addition of further loops of binding cord around the arms of the bow. Subsequent to this, the binding is frapped and "figure 8ed" like the plain and simple binding.

    Mac

    [img][/img]

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    Re: Prod bindings

    Post by mac on Thu Jan 05, 2012 3:26 pm

    stoneagebowyer wrote:Mac, what do you most recommend for binding material? I have always loved linen, but if you think another type of material is both authentic and servicable, please give us your suggestions.

    Dane

    Dane,

    Real bindings look like they are made of linen or hemp. I'm not at all sure I can tell the difference between them, but I am inclined to think I am seeing hemp. I have not been able to find any good hemp cord, to try it.

    I usually use cords that I have made by twisting together 6 or 8 linen shoemakers cords. I run the cord between two hooks in the shop; wet them down and twist them up. When it is dry, I take it down and use it to bind the bow.

    I've tried soaking the cord in wax to make it less susceptible to humidity changes, but that dosen't do it. The results are always the same, whether the cords are waxed or not....come winter, the bindings are loose. I count this as one of my nemeses.

    Mac
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    Re: Prod bindings

    Post by Ivo on Thu Jan 05, 2012 7:45 pm

    mac wrote:
    In the past, I have tucked the ends through the bundle of parallel
    cords between the figure 8s and the bow, but that's difficult, and never
    looks right. I have also brought the end back under the last turn of
    the figure8s, but I haven't seen anything like that in surviving
    bindings.

    I depicted the end simply tucked in between the
    bindings and the tiller, because I have not found evidence for anything
    fancier. The very end of the cord is not under any real tension, and
    the bindings are typically covered with some sort of glue.

    When
    bindings get loose, it is either because the linen has stretched, or
    the wood has collapsed. It is never a case of the figure 8s or the
    frappings slipping. All in all, I think it will stay just fine without
    any sort of knot.

    Thanks for the explanation. I also think one should be able to tuck the loose ends under the wrap, and as you said it must be a tight fit, but that might be a good thing and exactly what I'm thinking of doing when I get to that step in this one build I'm planning.

    I've tried soaking the cord in wax to make it less susceptible to
    humidity changes, but that dosen't do it. The results are always the
    same, whether the cords are waxed or not....come winter, the bindings
    are loose. I count this as one of my nemeses.

    The few bindings that I've looked at don't seem to be soaked in wax, but rather oily from constant handling. And then again, the other few do seem to be waxed or impregnated with resin like concoction(the *really dirty looking ones* Razz)...still, the best solution I think would be a fresh tight binding...even Samurai got their katana tsuka-ito re-wrapped after a while.

    mac wrote:Here is the next installment.

    I think I've also seen this wicked bind...never so explored though. Thanks for another great addition, Mac. It's truly great having you here with us! Smile

    Ivo




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    Re: Prod bindings

    Post by stoneagebowyer on Fri Jan 06, 2012 9:18 am

    My experience with linen tells me it is not particularly stretchy, so is there anything that can be done to minimize loosening bindings when using that material?

    My thought here is that since part of building historic (or based on) medieval weapons, the inherent weaknesses of the orginal materials are a great teaching tool.

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    Re: Prod bindings

    Post by mac on Fri Jan 06, 2012 10:11 am

    Dane,

    I think that this is what is happening....

    When the humidity increases, the bindings get tighter. This is for two reasons. The first is that the wood of the tiller (and the prod) swells.

    The second is that the linen contracts. This is typical of linen threads. The fibers swell in diameter, and because the thread is (of necessity) twisted, it gets shorter.

    Something has to give; and it is either or both of these things....Either the wood suffers pertinent deformation in compression.... And, or, the fibers of the linen slip past one another in order of accommodate the tension. In either case, the system has yielded plastically, and has suffered a slight but permanent deformation. Thus, when the humidity drops again, the whole thing is slightly loose. If left to its own, it will be tight again under high humidity, but that dosen't help us shoot our bows in the winter.

    It seems to me that one possible solution is to incorporate something slightly elastic in the system. Nylon cords will work, but that is certainly not the authentic way. Some sort of elastic pad where the prod sits in the tiller might work. Another possibility is the use of horn reinforcements where the cords bare on the hole in the tiller. I have used bone here, but it is not very elastic. But, then again, such reinforcements are far from universal; so that can't really be the answer.

    Another possibility might be to exercise greater discretion when tightening up the bindings in the first place. I have always tightened them up as much as possible, but perhaps that is an error. Perhaps they must be "just tight enough", and by this means we might avoid over stressing the materials when the humidity rises.

    Just "thinking out loud"....
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    Re: Prod bindings

    Post by mac on Fri Jan 06, 2012 10:20 am

    Ivo wrote:

    The few bindings that I've looked at don't seem to be soaked in wax, but rather oily from constant handling. And then again, the other few do seem to be waxed or impregnated with resin like concoction(the *really dirty looking ones* Razz)...still, the best solution I think would be a fresh tight binding...even Samurai got their katana tsuka-ito re-wrapped after a while.

    Ivo,

    I know exactly the sort of dirty bindings you mean. What is your impression of the material that is coating them? Do you have any theories about what substance of substances the coating in made of?

    Ivo wrote:
    I think I've also seen this wicked bind...never so explored though. Thanks for another great addition, Mac. It's truly great having you here with us! Smile

    Ivo

    Thank you!

    I have been worried about those holes for a while, and I have finally gotten the pictures I need to begin to understand them.

    Mac
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    Re: Prod bindings

    Post by stoneagebowyer on Fri Jan 06, 2012 11:25 am

    I guess Mac that ideally, you would want to bind your prod in during the times of less humidity, like around this time of year, but that is not practical. Best would be to live in a dry climate, such as the Great Basin, or perhaps the Mojave region of California. Most of us can't do that, of course. A totally synthetic crossbow would solve the issues, but who wants that in a medieval style? I wonder if one could slip a kind of shim between the tiller nose behind the binding and the binding cordage? Maybe made of horn? Or maybe there is a way you could bind it on and then be able to tighten things up in winter, and loosen them a bit in summer? Dane
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    Re: Prod bindings

    Post by mac on Fri Jan 06, 2012 1:41 pm

    A horn shim or pad under the prod is an interesting idea. In order to work, the horn would have to be able to compress elastically under pressures which do not compress the wood plastically, or cause permanent stretching of the bindings. To know if this is true, we need some numbers....

    Is there a material scientist in the House!?!

    this all got me thinking of something I saw a few months ago in a picture that someone showed me. The pic was of the socket of a tiller in Berlin. The bow was long gone, and you could see that the surface the bow was to bear on was sort of hollowed. This worried me. It seemed like supporting the bow on the resulting thin edges of wood was a recipe for trouble....but if we presume that the hollow is a place for a pad, it begins to make sense.

    Here is my sketch of what the prod socket of this bow looks like. I wonder if this is at all typical.

    Does anyone have any other pictures of empty prod sockets which show the shape of the bearing surface?

    Mac

    [img][/img]
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    Re: Prod bindings

    Post by stoneagebowyer on Fri Jan 06, 2012 4:18 pm

    Hmmmm...interesting. I think generally, people put a strip of leather between the prod socket and the belly of the prod. I do. I wonder if this is something like that, but with a more sophisticated purpose.

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    Re: Prod bindings

    Post by Ivo on Fri Jan 06, 2012 11:10 pm

    Damn it...lost my post! Mad Happens here sometimes...for those who missed this topic, go check it out and save yourself some trouble. >>> "No More Lost Text"

    So yeh...back to the beginning...

    mac wrote:
    Ivo wrote:

    The few bindings that I've looked at
    don't seem to be soaked in wax, but rather oily from constant handling.
    And then again, the other few do seem to be waxed or impregnated with
    resin like concoction(the *really dirty looking ones* Razz)...still,
    the best solution I think would be a fresh tight binding...even Samurai
    got their katana tsuka-ito re-wrapped after a while.

    Ivo,

    I
    know exactly the sort of dirty bindings you mean. What is your
    impression of the material that is coating them? Do you have any
    theories about what substance of substances the coating in made of?


    To be honest with you *have mercy* Laughing...I was planning on getting some exterior paint, diluting it with some spirits, heating and rubbing it into the cordage for my future attempt at one of these bows. I stumbled upon this craziness when looking up resin glue recipes when hanging out at a traditional bowmaking forum. The site mainly dealt with hammock making and I quickly skimmed through the waterproofing section where the man said

    "The main problem of using cotton cordage is it soaks up a lot of water
    when wet. To waterproof the cordage, natural materials could be used,
    however, for simplicity I used green external gloss paint, which seems
    to have done the job ok (time will tell)"


    But then he comes back to resin glue preparation, but doesn't seem to relate it to waterproofing...still it leaves me wondering. (Personally) I think that if pine resin was mixed with wax (say...paraffin) we can probably get a combination of paraffin's plasticizing effect and the improved water repellent properties of the pine resin...or something of the sort. scratch

    I looked a bit more and found this Chemistry book that talks about "improvised waterproofing of military garments". [Edit]The mix of Paris green/paraffin/rosin/diatamacious earth is one fo the waterproofing solutions that confirms the possibility of the above being a practical solution...possibly even for the *period*. Smile



    [Note: Scrolling feature sucks, just use the mouse to grab the page and drag it up to read further.]

    There is also a word on using "Green of Paris" as a part of the mix. As I understand it's a sort of natural dye? If so, the nit might explain the bright green bindings seen on those sweet little German bows on Halvslak's forum. I'm tempted to go take another dive in there.

    Ivo




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    Re: Prod bindings

    Post by stoneagebowyer on Sat Jan 07, 2012 3:43 am

    A few words regarding waterproofing cordage.

    Sailing ships back to antiquity used pitch to waterproof or protect ropes and cordage

    A quick glance at a medieval arrow discussion on another board came up with an Arabic bowstring recipe for silk bowstrings that was 5 parts beeswax, 10 parts resin, and 20 parts fish glue.

    My own experience with pine pitch is for stone age equipment. I heat up pine pitch and mix in some charcol. The charcol seems to make the pitch less brittle. It is tricky to control and hardens pretty fast, and if you get it on bare skin, it feels not so good.

    I also saw a reference to a thing called cordwainers coode. The guy writiing about it said we dont have the exact recipe, but it probably had pitch, resin, oil or beeswax in it, and was used for crossbow strings.

    Could the green you mentioned by veridian, as used in the fletching of medieval arrows?

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    Re: Prod bindings

    Post by Ivo on Mon Jan 09, 2012 12:17 am

    I hope you guys were reading up on the subject outside the forum Cool ....anyways, I did. Laughing

    Paris Green....quite a history on that one. Smile

    Turns out it's a Coppper/Arsenic compound that was mostly used as a rodenticide/insecticide due to it's wonderful toxicity ("...once was used in Parisian sewers to kill rats, hence the common name..."), but despite that, it was also used as a pigment in paints and inks for it's vibrant blush green tint.
    Now I can somewhat understand why it was mentioned in the fabric/cordage treatment solution (and not necessarily as a pigment or a waterproofing agent). As the book said, it was used in very small amounts and was basically there to prevent the clothing from being infested with insects (I'm guessing lice, fleas, and other parasites...as well as to prevent the clothing from being chewed up by rats - perhaps while in storage). Not sure if it was a good fungicide/preservative (as that would be a good property in the waterproofing solution). - Here's the "Wiki"

    Viridian is a bit different, though also green, it's actually a Chromium compound and is primarily used as a pigment. - "Wiki"

    Also it's interesting that you mentioned Sailing ships, because that really rang a bell - Vikings!!!

    There is a whole article on the reconstruction of their longboats that had wool sails. And there is much said about fabrication and preparation, a good part of whic is...you guessed it - waterproofing and tensile strenth.
    "PDF Link" ...pretty cool stuff actually.

    Here is a quick cutout...

    ...

    Air permeability and smo¨rring (dressing)


    During sail fabric testing at UMIST in an attempt
    to understand the functioning of wool sails the
    decision was made to test air permeability. The
    Shirley Air Permeability Tester was used on the
    Skuldelev 1 replica fabric and on other similar test
    fabrics. Initial tests showed that the fabrics had
    such high permeability that the standard pressure
    drop of 10 mm water pressure could not be
    achieved at the highest flow rate. The test was
    modified to 2 mm water pressure before readings
    could be taken that were typically between 100–
    150 cc/sec flow rate. Fabrics with such high permeability
    would not function as sails because air
    would flow through the sail and eliminate the
    pressure difference between the front and rear that
    creates the draw. It had been suggested that half
    Figure 3. Schematic diagram of the Otar square sail. (Drawing:
    Viking Ship Museum)
    NAUTICAL ARCHAEOLOGY, 31.2
    208
    fulling the fabrics would reduce the permeability
    but tests on loom-state and fulled fabrics showed
    that air permeability was typically only reduced
    by 30–35% by fulling, which was not enough to
    resolve the problem.
    A fragment of the Nordmore sail was then
    tested under the same conditions and was found
    to have much lower air permeability, 10–20 cc/sec.
    The Nordmore sail had been impregnated with a
    resin like finish and this tied-in with comments in
    the literature about smo¨ rring (Andersen, 1995).
    Smo¨ rring involves a two-stage process of, firstly,
    brushing into the fabric an emulsion of water,
    horse fat, (from beneath the mane) and ochre.
    This is allowed to dry and then hot liquid beef
    tallow is rubbed and smoothed into the sail
    .
    This
    process was used twice to improve the light
    stretchy sail of the Roar Ege and was also applied
    to the Sif Ege sail (Andersen, pers. comm.). To
    establish the effect of smo¨ rring, the Skuldelev 1
    fabric and the other test webs were tested before
    and after treatment and as part of this experiment
    the extension of a 5 cm strip at 100 N loading was
    also measured before and after. The air permeability
    tests show that smo¨ rring dramatically
    reduces the airflow. The sample SK1/4,
    (Skuldulev 1 oppsett 4) shows that a high air
    permeability of 111 cm/sec can be ‘tuned’ down to
    4 cm/sec by the two stage process of horse fat and
    ochre followed by beef tallow. The results for
    Skuldelev 1 oppset 2 and Skuldelev 1 oppset 5,
    both show the effect of each of the two stages. The
    first application lowered the air flow from 68–
    85 cc/sec down to 18 cc/sec, and the beef tallow
    application reduced it further, to close to zero if
    required, dependant on the quantity of beef tallow
    applied. The other interesting result is that the
    three warp-weighted loom fabrics included in this
    test, AN1, AN2 and BF all give air flow values in
    the region of 30 cc/sec prior to smo¨ rring and this
    suggests that it is easier for a woman of average
    strength to produce a very tight fabric on a
    warp-weighted loom as compared with the horizontal
    loom fabrics which all have initial air flow
    values above 62 cc/sec, (62–111).
    Finally the 5 cm strip testing demonstrated that
    smo¨ rring reduced the low load (100 N/5 cm) extension
    by approximately 30–40%, thus increasing
    the tensile modulus accordingly. Smo¨ rring can
    therefore be seen as an important aid in the
    successful use of coarse woollen sails. It enables
    the air permeability to be reduced to a level at
    which the sail will develop a good draw and it also
    has the effect of trimming the elasticity of the sail.
    The inclusion of ochre in the mix is also of
    significance. It undoubtedly acts as a good filler
    inhibiting air flow by filling the voids in the fabric,
    but it also has anti-bacterial properties which help
    to prevent the wet sail from rotting.


    Conclusions

    The experimental archaeology associated with the
    reconstruction of woollen sails for the reconstructed
    Skuldelev ships has radically altered the
    understanding of the functioning and efficiency of
    such sails. In 1975 Svend Larsen concluded his
    book, Vikingsernes hav, by stating that beating to
    windward cannot be done with woollen sails
    because they are ‘fleecy, nappy, yielding and
    leaky’ (Larsen, 1975). It is now known that high
    cover factor woollen square-sails could beat at 66
    into the wind and most likely out-perform linen
    and hemp sails. Furthermore it has been proved
    conclusively that the process of smo¨ rring enables
    the properties of the wool sail to be improved and
    ‘trimmed’ during use.
    In a small way the research carried out at
    UMIST as part of the Raphael ‘Seafaring’ project
    has added to the understanding derived from
    experimental archaeology by providing comparative
    quantitative data within a framework of the
    fibre physics and fabric mechanics essential for
    the evaluation of the results. It is to be hoped that
    this work will help to provide the foundation for a
    better understanding of the design and performance
    of woollen square-sails together with a
    clearer appreciation of the high level of technical
    skills and knowledge developed empirically by our
    forebears.

    And last - one of my favorites since I've dealt with it quite a bit when trying to make some homebrew metal casting investment - Diatomite (Diatomaceous earth) mentioned in a few recipes...

    The Wiki pretty much covers all the good stuff, so here is a "Link"

    Diatomaceous earth ( /ˌd.ətəˌmʃəs ˈɜrθ/) also known as diatomite or kieselgur/kieselguhr, is a naturally occurring, soft, siliceous sedimentary rock that is easily crumbled into a fine white to off-white powder. It has a particle size ranging from less than 1 micrometre to more than 1 millimetre, but typically 10 to 200 micrometres.[1] This powder has an abrasive feel, similar to pumice powder, and is very light, due to its high porosity. The typical chemical composition of oven dried diatomaceous earth is 80 to 90% silica, with 2 to 4% alumina (attributed mostly to clay minerals) and 0.5 to 2% iron oxide.[1]

    Diatomaceous earth consists of fossilized remains of diatoms, a type of hard-shelled algae. It is used as a filtration aid, mild abrasive, mechanical insecticide,[2] absorbent
    for liquids, matting agent for coatings, reinforcing filler in plastics
    and rubber, anti-block in plastic films, porous support for chemical
    catalysts, cat litter, activator in blood clotting studies, and a stabilizing component of dynamite. As it is also heat-resistant, it can be used as a thermal insulator.
    Very interesting properties that make up a really cool picture when the other ingredients are brought into play. drunken
    As I remember, diatomite...aka kieselgur...aka diatomacious earth...was a major component in the fabrication of cloth/cordage due to it's mild abrasive properties that helped soften and cleanse the raw material of impurities like oils and foreign/large particles like dirt and bark(which was normally done by physically beating the material or literally stomping it by the workers feet)....as well as it's absorbing properties that allow it to retain whatever compound it is mixed with.

    Ok, I'm off to go do stuff, but this topic has me rolling. Laughing

    Ivo




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    mac
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    Re: Prod bindings

    Post by mac on Mon Jan 09, 2012 8:43 am

    This all goes to show that our ancestors did some wild and ingenious stuff. How do people think of these things? They have my greatest admiration.

    Smorring clearly shares etymological roots with Smørrebrød, which is the Danish word for "buttered bread". The Swedish equivalent, "smörgås" gives us the ever-popular "smorgasbord"; a meal of open sandwiches on buttered bread.If you use your viking ship's sail as a shelter for your smorgasbord, you had better not smoke after dinner, though: that thing could go up like a candle!

    I have been thinking on the subject of bindings and humidity changes, and talking it over with a friend who is a mechanical engineer. We came to a couple of conclusions, and thought of a few experiments to perform.

    Our first conclusion was that horn would probably not be a good choice for providing an elastic buffer against humidity induced dimensional changes in the wood-linen system. Horn is just plain harder than wood, and if you squeeze the two together, the wood will dent before the horn compresses. The fact that you can dent most woods with your fingernail is sufficient to demonstrate this.

    Our next conclusion was that it was probably not possible to seal the linen tightly enough against water that seasonal humidity changes would not effect it. It's a lot like the question of sealing wood. You can slow down the rate in which the material gains and looses water, but you can not really stop it. The historical coatings on the bindings were probably there to guard against occasional rain.

    We devised a series of experiments to determine whether the culprit was the linen, the wood, or both. These experiments will involve binding metal with linen, and binding wood with metal etc., and subjecting them to cycles of humidity changes. I will try to do these sometime this winter.

    The other experiment we thought of is to test the idea that I have been binding my bows too damn tightly in the first place. The presumption is this. If the bindings are too tight, one or more of the system might already be near to their yield points and, that dimensional changes wrought by seasonal humidity swings may be sufficient to cause permanent deformation. By contrast, if the bindings were "just tight enough" to do the job, it might be possible that the system has enough elastic "give" to survive these changes without ever inducing plastic deformation. To investigate this idea, I plan to bind up a model under low humidity conditions and then subject it to one or more cycles of high humidity to see if the bindings will remain tight enough to do its job.

    Mac









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    Re: Prod bindings

    Post by stoneagebowyer on Thu Jan 12, 2012 4:13 am

    Good thing the ancient Norse hadn't invented cigs. Better to die in battle like honest and healthy Vikings.

    I agree on your assessment of horn. Horn in composite bows of course is exceptionally suitable for tension, but not compression.

    I am very much looking forward to the experiments and what they yield. And I agree with you about "waterproof:" coatings being used to protect things against light weather conditions. Ancient armies I imagine didn't fight in pouring rain for that reason alone.
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    Re: Prod bindings

    Post by basileus on Thu Jan 12, 2012 9:46 am

    mac wrote:Over on this thread, http://thearbalistguild.forumotion.com/t525p15-leather-braiding-to-bind-on-stirrup#4593 there was a call for information on how prods are bound into the tiller.

    Here is my first series of instructional sketches. It shows what might be described as a "plain and simple" binding. There is nothing here that most of you don't know already; but it should serve as a sort of jumping of point for the discussion of more complicated bindings.

    Mac

    Wiki police here Smile. Why not put these images as a tutorial into our Wiki? Much nicer place to look for information than a forum, where the stuff is "all over the place". You don't even have to create a user account if you don't want, WIkia allows anonymous contributions.
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    Re: Prod bindings

    Post by mac on Thu Jan 12, 2012 10:47 am

    Basileus,

    You may feel free to put my diagrams in your Wiki if you wish.

    Mac
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    Re: Prod bindings

    Post by Basilisk120 on Mon Jan 16, 2012 3:48 pm

    mac wrote:I have been thinking on the subject of bindings and humidity changes, and talking it over with a friend who is a mechanical engineer. We came to a couple of conclusions, and thought of a few experiments to perform.

    Our first conclusion was that horn would probably not be a good choice for providing an elastic buffer against humidity induced dimensional changes in the wood-linen system. Horn is just plain harder than wood, and if you squeeze the two together, the wood will dent before the horn compresses. The fact that you can dent most woods with your fingernail is sufficient to demonstrate this.

    Our next conclusion was that it was probably not possible to seal the linen tightly enough against water that seasonal humidity changes would not effect it. It's a lot like the question of sealing wood. You can slow down the rate in which the material gains and looses water, but you can not really stop it. The historical coatings on the bindings were probably there to guard against occasional rain.

    We devised a series of experiments to determine whether the culprit was the linen, the wood, or both. These experiments will involve binding metal with linen, and binding wood with metal etc., and subjecting them to cycles of humidity changes. I will try to do these sometime this winter.

    The other experiment we thought of is to test the idea that I have been binding my bows too damn tightly in the first place. The presumption is this. If the bindings are too tight, one or more of the system might already be near to their yield points and, that dimensional changes wrought by seasonal humidity swings may be sufficient to cause permanent deformation. By contrast, if the bindings were "just tight enough" to do the job, it might be possible that the system has enough elastic "give" to survive these changes without ever inducing plastic deformation. To investigate this idea, I plan to bind up a model under low humidity conditions and then subject it to one or more cycles of high humidity to see if the bindings will remain tight enough to do its job.

    Mac

    I am interested in your conclusions when you reach them. Living in the desert I see this first hand quite a bit. In the rainy season things fit togather nicely for a couple of days but soon the humidy drops and things loosen up, being that most of what I have was made in areas with humidity.

    I think your concluctions on elastic buffers sounds good. So what might work? I was going to suggest leather as a buffer material but I think that would make things worse, since its swells when wet and shrinks when its drys out.

    The best suggestion might simply be that the prod is tied on "just so".



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    Re: Prod bindings

    Post by Armbrustier on Mon Jan 23, 2012 9:09 am

    Hi Mac!

    Some nice drawings you have made! Just one question; what do you do with the endings? I don't think I have seen any loose ending on any crossbow.

    /Micke Dahlström,

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    Re: Prod bindings

    Post by Armbrustier on Mon Jan 23, 2012 9:24 am

    One idea for a tighter binding could be to make it during the winter time when it's a lot drier in the air, and both the tiller and the binding material would be as dry as they get.

    I don’t think anyone, today, knows how often they needed re-binding in the past, if they had a way to do it tighter than we do, or if they re-did it once a year?

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