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    1000 lb. plus crossbow...

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    olrono
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    1000 lb. plus crossbow...

    Post by olrono on Thu Oct 18, 2012 7:30 pm

    I don't want to make the same old stuff
    again that every one here has made before. So, what is it that none
    of you guy's has ever made or even seen? A 1000 lb. PLUS crossbow!

    I intend to have the spring made for me
    by a spring fabricator that makes and repairs heavy equipment. I
    am thinking the bow stave will be over all length 40” and 3”
    wide and ½ inch thick! The tiller will be made as a platform to
    accommodate this bow and not necessary pretty. I will use a


    4 x 6 Douglas fir with 1/4” steel
    plate on the sides from the 'bow notch' up to the lock. The 'roller
    lock' will be made from steel. I am thinking the socket will have to
    be made from a solid metal block with a hole in front of and behind
    the socket to be mounted between the side plates with bolts to hold
    this tremendous force. Even the axle for the tickler will have to go
    through these heavy side plates.

    The bow it self will be attached to the
    front of the tiller with the same size U-bolts that hold them on an
    axle of a semi trailer. A 2” pipe will go through the tiller and
    side plates about 10 inches from the bow notch and the 'round' part
    of the U-bolts will be held on the pipe there. A steel plate or
    saddle will hold the bow stave on front with four holes that the
    U-bolts pass through and can be 'torqued' to this arrangement and
    'checked' at anytime.

    The only area that I am not that sure
    of is the size of the roller and the tickler were the sear and
    release take place? Every thing else is very solid and I don't want
    this monster to explode in this weak area.

    I want this thing when it is fired to
    make a very loud bang and see a little 'smoke' come off it. If you
    know what I mean? Can't wait to read your comments on this one...
    Rolling Eyes

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    Re: 1000 lb. plus crossbow...

    Post by Rizzar on Fri Oct 19, 2012 12:16 am

    Don´t want to calm your enthusiasm down, but I would assume crossbows over 1000lbs were not that uncommon.
    Today they are quite rare because the use of them is very reduced.

    To your plans:

    Douglas Fir?? You want to build really heavy "artillery", you should use quality choice hardwood (e.g. Oak or good Ash).

    You should consider about getting a real crossbow prod forged for you by a specialist (could assume the costs of a spring made for you could be near the costs for a pro made crossbow prod). And the safety aspect would benefit from a proper made prod.

    Do not forget you will have to use a multi axle lock (4-5) to reduce the power to a workable amount in the trigger section.

    As for your roller nut dimension: if you make it from solid steel there should be no problem with a normal diameter size roller nut. I assume, if you make a roller nut much larger in diameter than normal, it would have negative effect on the forces in the nut axle (lever effect). The nut fingers should acommodate the string (hopefully from modern string material) safely.
    You should make it a bit wider than normal.

    Besides that the amount of force in the areas behind the nut is decreased significantly by every axle.

    I do not understand your bow placing mechanism that good, because of language/imagination difficulties, but I want to recon that you are not drilling a whole lot of holes through your tiller front?



    To point out one thing: crossbows with that amount of force are not often built because the builders can´t do the job. The are not because there is not much use for them.
    They are very uncomfortable and really dangerous to handle. Imagine a breaking +1000lbs prod or the string of it while you are close !?!
    Fragments can be deadly missiles.
    Every spanning process will take its time, since you need a (very good) cranequin or windlass.
    The amount of power transfered to the bolt would not raise very much compared to a (weaker) bow with longer acceleration distance (the stronger the bow the shorter the distance)
    You would only be able to shoot a bit heavier bolts which gives you more energy in the target, but to be honest what would you want to do with that. You could kill an animal with much less efford.

    But I wish you really good luck, I am very curious to see the evolving process.

    p.s.: just because it is powerful it doesn´t have to be ugly ;-)
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    Re: 1000 lb. plus crossbow...

    Post by Todd the archer on Fri Oct 19, 2012 2:15 am

    Something that heavy probably would work best on a tripod support. Also going to need larger stronger bolts maybe 1/2" diameter or larger.



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    Re: 1000 lb. plus crossbow...

    Post by Kale Schlegel on Fri Oct 19, 2012 11:10 am

    Sounds a wee bit ambitious, but I like that! Jam What will fire from it? trees? hah, damn siege machine !

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    Re: 1000 lb. plus crossbow...

    Post by chaz on Fri Oct 19, 2012 11:52 am

    Olrono,

    Might look good on a cannon type carriage and maybe a pully cable type cranquin mounted to the rear ................ once again pictures of your ideas would be helpful. Certainly an ambitious project to be approached with great planning, reasoning, and safety at the forfront. Wood and steel, cables, wheels, cranquin, cables, nuts and bolts , maybe compound with pullies to help with the spanning ............. GREAT !

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    Re: 1000 lb. plus crossbow...

    Post by ferdinand on Fri Oct 19, 2012 1:18 pm

    Medieval style heavy war crossbow that can take down a horse in armour!
    Me likie long time GI! Beaucoup power.

    Just be save.

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    Re: 1000 lb. plus crossbow...

    Post by olrono on Fri Oct 19, 2012 4:14 pm

    Been a truck driver over 30 years and know many guy's from the shop and the bow wont cost me a dime. As far as "4x6 Douglas fir", this only holds the 1/4" steel plates together on the sides of the stock from the front bow notch all the way back past the lock to 'hold' all the goodies in place. Essentially the "tiller" will be all steel as far as where the forces are concern.
    Being an "Old Guy", my grandson will post the pictures for me as I go along.
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    Re: 1000 lb. plus crossbow...

    Post by olrono on Fri Oct 19, 2012 6:11 pm

    [quote="Todd the archer"]Something that heavy probably would work best on a tripod support. Also going to need larger stronger bolts maybe 1/2" diameter or larger.

    Thanks for your comments Todd, I was thinking exactly that. As far as "bows existing in the past" as some here mentioned... I know they 'had them before', but has any one ever shot one? Or seen a modern one? I am aware in England "Todds Stuff" offers a "900 lb." crossbow made authentically medieval, but I wanted to utilize a leaf spring at a very high draw weight, so strong I wouldn't know even how to measure it.
    I know about "multiple axial locks", I don't have the knowledge to design one of those. I have heard they use those on lite weight stuff ? I have seen they even use a lock that is actuated from the 'top' and there is no 'tickler' on the bottom? The string re-lease has always been "the hard part". I have all ways seen "roller nuts" on these bigger bows. I would like to learn more about these "top release" devises.

    It's a good thing I don't design computers, I can't even post this right, sorry...
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    Re: 1000 lb. plus crossbow...

    Post by kenh on Fri Oct 19, 2012 7:44 pm

    I caught an episode of Rick Steve's European travel a couple weeks back. It was all about the mini-countries -- Vatican City, Lichtenstein and Monaco. At the castle in Lichtenstein they showed a couple guys in medieval costume shooting wall-mounted crossbows across the main courtyard at a target maybe a foot in diameter. They were massive, maybe 5 ft from prod to the end of the tiller. Equipped with built in cranequins, mounted on tilt & swivel axis mounts. They might be in your 1000 pound class of bow. Any of our Euro bretheran seen these in action?

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    Re: 1000 lb. plus crossbow...

    Post by chaz on Sat Oct 20, 2012 4:43 pm

    Olrono

    You might look up YouTube : Cupid's Manolescent Crossbow .......... Check it out !

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    Re: 1000 lb. plus crossbow...

    Post by Todd the archer on Sat Oct 20, 2012 5:14 pm

    This looks like what you are describing:



    Top release trigger:





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    Re: 1000 lb. plus crossbow...

    Post by Geezer on Sat Oct 20, 2012 9:18 pm

    Top release trigger: commonly used on catapults. String can't hop over the bolt, that's a plus. On the down-side, they tend to wear center-serving very fast. You have to take extra care. Once a single strand in the string breaks, it's doomed.
    Build it in hardwood, not Douglas Fir. If you've already bought the fir, use it for something else. Oak, Maple, Ash, Birch would all work.
    Be careful. Geezer
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    Re: 1000 lb. plus crossbow...

    Post by olrono on Sat Oct 20, 2012 9:54 pm

    Thanks guy's this picture shows what
    my crossbow will look like, but this one is for those games these
    medieval clubs play. I am sure they are having fun but the bow I am
    planning would tare this one up. The stock I am planning looks just
    like this but will have steel plates all along down the sides like a
    'sandwich' with the wood between the plates containing the lock
    mechanism. The bow stave will look just like this one only I/2 inch
    thick spring steel. I will have to use a bench press to affix the
    string, which by the way I am thinking will look as thick as a
    'medieval' string but will have to be made from Kevlar (fast-flight)
    to hold over a thousand pounds.


    So far I am working out my lock as a
    rolling nut two inches round and two inches across. With the sear
    going all the way across the whole roller, so the ticklers sear will
    touch the whole length. This of coarse means the tickler will be two
    inches across (beaver tail) and ½ inch thick and how ever long I
    will need to get a good leverage to release. It may not be the
    “smoothest” but it should work and hold two thousand pounds.
    Remember the socket blocks and nut are all held by the ¼ inch steel
    plates including the tickler lever axle, which will be a ½ inch
    grade eight bolt going through the tickler axle and stock plates.
    (just in case)


    I will use a “high lift jack” to
    span this bow. Which I will use to determine the spanning length. I
    will have to construct the bow first with out the lock, span the bow
    carefully little by little, listen for it to “creek”, then back
    off a notch. Ha! Then mark it there. Can't wait till tomorrow to
    get started...

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    Re: 1000 lb. plus crossbow...

    Post by 8fingers on Sat Oct 20, 2012 10:01 pm

    I have been in on the building of several ballistas like the one Todd posted pictures of. Plans are available on line.
    Thought about the U bolt mounting before I came upon the plans, and I think it is a good one.
    I tapered my prods and had a recurve rolled into them by the spring shop. Pin nocks or dove tail nocks are about equal with the recurve but suggest dovetails if you go without the recurve.
    I used a boat winch because my metal working skills are weak. Used a swivel mount on a double pedestal base. About as powerful as a 12 gauge shotgun at 350# pull. Helper springs boosted that some. Shot 1# bolts a little over 90 yards.
    Didn't need steel reinforcing plates on spruce stock. My friends machine is oak, with a great winch. Links to the video are posted in the 'I know its not a crossbow' thread. I will see if I can find the link to where I got the plans. They were $30, print or CD, bowstrings and a critical part were about the same each. Worth getting them.
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    Re: 1000 lb. plus crossbow...

    Post by olrono on Sat Oct 20, 2012 10:34 pm

    Thanks 8 fingers, those bows you spoke of sound great at that weight, but I am going all out with a heavy weight thousand pounder plus! I am interested in what you described as a re-curve? I plan on having the ends machined to hold the string but I don;t want it to fly off with the pins going strait out? I am a little unfamiliar with some of this terminology, but I know what I want when I see it. I want it to curve out a little but I don't want it to look as much as a re-curve bow as in regular archery. What do you call that?
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    Re: 1000 lb. plus crossbow...

    Post by olrono on Sat Oct 20, 2012 11:01 pm

    chaz wrote:Olrono

    You might look up YouTube : Cupid's Manolescent Crossbow .......... Check it out !

    Chaz

    Thanks Chaz, these guy's reminded me of Hank Williams "A Country Boy Can Survive". But I think they ruined a nice trailer making that crossbow.
    Sleep
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    Re: 1000 lb. plus crossbow...

    Post by Geezer on Sat Oct 20, 2012 11:22 pm

    Olrono: Remember that the number 1000 (as in pounds of draw) is just a number. 1000 lb. of draw at 10 inches is a lot more than 1000 lb. at 5 or 6 inches. There were lots of Medieval sporting bows made in the 1000 lb. range, but most of those were short, steel prods with very limited power-stroke (say 5-6 inches of stroke from 4 inches of brace) There's all the difference between those and siege-bows which might not draw much more, but have a foot of power-stroke. The greater the draw, the greater the stress on lock, including socket, nut, tickler, tickler-pin, etc. Greater length of draw also produces a better cast with heavier projectiles, but whatever you do, you won't get much over 200 fps with a steel bow.... okay, maybe 250, but that seems to be the limit for recovery speed for a steel bow. So a super-heavy bow won't shoot any faster, but it CAN shoot a much heavier bolt to the same speed. And if your bolt isn't heavy enough, you lose power and increase stress and recoil for the whole system.
    So you're gonna have to shoot this baby on a rifle-range, or at least out in the country, NOT your back yard. You'll need a very stout target to stop the bolts, and if your target is hard, you're gonna break a lot of bolts, even if they're made of the best available materials. And in the end, you won't really have a very powerful weapon, compared to modern firearms. Otherwise, why do you suppose armies gave up crossbows for arquebuses. Even the old matchlocks got much more power into the projectile/target.
    I scratch my head in bemusement. Why would anybody want to put so much effort into something that'll come out ugly and cobbled together, when with a little more work, you could make something beautiful, whether modern or ancient in design?
    Ahh well, have fun stormin' da castle... and wear a helmet when you test it. Geezer

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    Re: 1000 lb. plus crossbow...

    Post by chaz on Sun Oct 21, 2012 3:03 am

    Olrono,

    Sometimes you need to look at the "JUST FOR FUN" aspect .

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    Re: 1000 lb. plus crossbow...

    Post by Geezer on Sun Oct 21, 2012 9:10 am

    WHATTT? Just for fun? Next thing you know, I'll be hearing about 8- hour workdays or weekends off! Where's your dutiful work-ethic? I wanna see you working your fingertips raw! Just ask my apprentice if you don't believe me!
    Well okay, you can have a leeetle bit of fun, but don't make a habit of it!
    That's what I get for turning my hobby into a business. Geezer
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    Re: 1000 lb. plus crossbow...

    Post by olrono on Sun Oct 21, 2012 9:26 am

    Geezer wrote:Olrono: Remember that the number 1000 (as in pounds of draw) is just a number. 1000 lb. of draw at 10 inches is a lot more than 1000 lb. at 5 or 6 inches. There were lots of Medieval sporting bows made in the 1000 lb. range, but most of those were short, steel prods with very limited power-stroke (say 5-6 inches of stroke from 4 inches of brace) There's all the difference between those and siege-bows which might not draw much more, but have a foot of power-stroke. The greater the draw, the greater the stress on lock, including socket, nut, tickler, tickler-pin, etc. Greater length of draw also produces a better cast with heavier projectiles, but whatever you do, you won't get much over 200 fps with a steel bow.... okay, maybe 250, but that seems to be the limit for recovery speed for a steel bow. So a super-heavy bow won't shoot any faster, but it CAN shoot a much heavier bolt to the same speed. And if your bolt isn't heavy enough, you lose power and increase stress and recoil for the whole system.
    So you're gonna have to shoot this baby on a rifle-range, or at least out in the country, NOT your back yard. You'll need a very stout target to stop the bolts, and if your target is hard, you're gonna break a lot of bolts, even if they're made of the best available materials. And in the end, you won't really have a very powerful weapon, compared to modern firearms. Otherwise, why do you suppose armies gave up crossbows for arquebuses. Even the old matchlocks got much more power into the projectile/target.
    I scratch my head in bemusement. Why would anybody want to put so much effort into something that'll come out ugly and cobbled together, when with a little more work, you could make something beautiful, whether modern or ancient in design?
    Ahh well, have fun stormin' da castle... and wear a helmet when you test it. Geezer

    Thanks Geez, I am up to speed on all
    issues you raised. I am disappointed with this “speed of
    steel”thing, that is why I planed this new project with a 40”
    long prod giving me what I hoped a 14” draw. With my knowledge of
    these springs, they don't bend all that far. This does have me
    concerned as well as there slow, and I don't want a “lack luster”
    project as Chaz's video with the 'good o' boy's' having fun. I just
    bought a little trailer that size and I wouldn't want to cut it up
    just to shoot a 4” ABS pipe at a scarecrow. I want to say I always
    like your comments here Chaz I am with you on the 'fun' angle!
    That's kinda why I want a BIG powerful crossbow to shoot a 1 inch 20
    inch long bolt a thousand yards... But if 'steel' can't get me
    there, maybe I'll go back to brain storming on the prod material.
    Fiberglass is the closest thing to those “bone and fish glue”
    composite prods these big babies really used. I am going to go that
    way, I know my 'fiberglass' bows always were my hottest crossbows as
    far as 'speed' is concern. Thinking... “Where can I find a really
    big fiberglass prod?” Oh yeah Geezer, I don't want to create
    another thing of beauty, the bow you made for me will never come off
    it's pedestal!
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    Re: 1000 lb. plus crossbow...

    Post by Geezer on Sun Oct 21, 2012 10:43 am

    Olrono: I hate to rain on your parade. Fact is, if you wanna shoot a one-inch steel pipe 1000 yards, go to gunpowder. The most efficient arrow-shooters I know are torsion-ballistas. Based on medieval/Roman practice, even they are limited to @ 500 yards.
    Beyond a certain point, bow-technology begins to run into problems of scale. So a 500 lb. bow shoots further (with a heavy bolt) than a 250 lb. bow, but not much. A 1000 lb. bow shoots a leetle better, but a heavier bolt, but as you go up the scale, you run into more structural problems for less improvement.
    Changing to modern materials, like carbon-fiber or fiberglass, will give you somewhat higher velocities, but consider if you will that outfits like Excalibur and Horton spend plenty of research money on special materials and mechanicals, and as far as I can see, even the best commercial bows don't get much over 400 fps. If you want more, you have to go to expanding gas in a closed pipe... Bammm!
    So build what you want, and enjoy... safely, but understand there really are limits to what bow-technology will do!
    But DO have fun. DRW/Geezer

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    Re: 1000 lb. plus crossbow...

    Post by chaz on Sun Oct 21, 2012 12:00 pm

    Now Geezer,

    Obviously if you enjoy what you are doing........ you are not working.......... you are really living !

    Far better than just existing.

    Chaz
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    Re: 1000 lb. plus crossbow...

    Post by Kale Schlegel on Sun Oct 21, 2012 4:39 pm

    I'm going to frequent this post a lot , I cant friggin wait to see the progression pics!

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    Re: 1000 lb. plus crossbow...

    Post by 8fingers on Sun Oct 21, 2012 8:54 pm

    First a recurve is a recurve, like being a little bit pregnant. Means the tip bends forward enough the string touches the bow limb somewhere before it touches the nock. Bending just a little bit of the end for the nock would work but a more sophisticated recurve changes the energy storage curve, sometimes dramaticly. I cut my nocks by clamping a straight edge along my cut and used a 4 1/2 in angle grinder with the thinnest cutting wheels I can find. heating to a forging heat and running through a swedging die would work too. The swedging rigs I'm thinking of are used to crimp fittings onto cables and hydraulic lines.
    The plans I mentioned can be used as an R&D platform by adding helper or backer springs until you work up to target weight.
    Roller nut releases are historic but some of the releases shown on the "Crossbowman's Den" website could be scaled up to give you a reliable trigger with faster reloads and more reliable resets. Might be worth making a test sled for your trigger releases so blow ups don't take more of your engine with it.
    By my reading it appears 1200# bows with 6" draws were in use in siege situations and were still man packable but rested on a parapet or breastworks. Some of our Swedish counterparts seem to be building crossbows of nearly the weight you desire. Learning from their failures could be as instructive as their successes.
    ballistaplans.com is where I got my plans from.
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    Re: 1000 lb. plus crossbow...

    Post by olrono on Sun Oct 21, 2012 10:22 pm

    Kale Schlegel wrote:I'm going to frequent this post a lot , I cant friggin wait to see the progression pics!

    Yeah man I can't wait to post them, isn't life great!!!

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    Re: 1000 lb. plus crossbow...

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      Current date/time is Tue Aug 22, 2017 6:48 pm