Here's my preliminary sketch for the Chu-ko-nu. The magazine in the original is usually made out of a single piece of wood with the centre hollowed out but I've decided to go with separate pieces instead to make it easier to build. I've yet to decide on the scale so there are no dimension on the sketch but I'm thinking of making one with an overall length of only about 10".

I will be posting periodically here to post the progress of the construction from start to finish.

(Disclaimer: Making a real cross-bow is illegal in most countries. If you make a life-sized one based on my designs, you do so at your own risk. These designs are meant only for a small scaled model "toy". The author will not be held liable for the use for the plans above. Usage is at your own risk and discretion and have been provided only for academic purposes.)



Magazine & Trigger Elevation & Details


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Construction Begins!

26th April 2005 - Finally worked out the required dimensions and material to use. Got most of the wood I need, mainly Basswood.


29th April 2005 - I'm somewhat finished machining most of the main pieces. The most complicated was the trigger pin and slot which took about 2 hours of careful chipping, cutting, planing and scrapping.


30th April 2005 - Ahh... I've started assembling the pieces. The trigger and magazine are a little tricky as every piece has to fit perfectly and once glued together, it'll be very tough to correct mistakes. Just cutting and fitting the grooves and slots took me hours to do, adjusting one way then another.


1st May 2005 - Finally it's taking on a more recognisable form. The magazine, trigger and pull-handle and main body are done, but I've yet to find the right piece for the bow arms.


2nd May 2005 - Ok, only the bow arms and bow string left to make. This will take a little bit to tuning to get it just right as the magazine must be able to catch the string and still have sufficient draw to shoot the arrow.


9th May 2005 - Still doing minor retuning. I've gone through 2 bows now, both snapping when tensioning... or rather overtensioning. This is the magazine cover in detail.


10th May 2005 - Done! 3rd attempt at the bow arm. Made it longer this time. Here's the completed zhugenu.


Another view with insert showing the corking action (magazine raised)

Just a couple of questions, Jieming.

When you go about making the, were you mainly interested in replicating them the way they were designed/made in the past?

Or did you also think about given the level of technology at that time, how the design could have been further improved?

For one thing, I am curious to know whether it would have been more useful to mount these weapons on tripods.

The modern tripods allowed most weapons to be set up in various terrains, including uneven, sloping, etc, because their legs were adjustable. They not only provide a stable base, but also allowed for the weapons to be redirected easily.

Would such an implement be achievable in the past before the sophisticated engineering of extendible metal/alloy hollowed legs?

I tend to go for historical accuracy though I do make slight modifications for ease of construction since I don't have the time or sometimes the tools for really complicated work. :-)

I don't know if they used them on tripods since these were relatively light weapons and could be carried by soldiers. This is the site I'm basing the chu-ko-nu on and it is a write-up on an actual weapon. According to the author, it weighs only 3 lbs.

I'm sure tripod technology wasn't beyond the ancients, especially the Chinese since if making hollow tubes are a concern, they did have bamboo! As for extendable legs, well... probably not but foldable legs are definitely possible.

http://www.arco-iris.com/George/chu-ko-nu.htm

Greetings,

Also see here:

http://www.atarn.org/chinese/yn_xbow/zhugehtm.htm

for a discussion and some more diagrams.

Good luck!

Daniel Slone

Cool stuff. ... I wonder if your cross-bow can be done with a lego set. ...
... If you were to build a "real deal" crossbow, What type of materials will you use to assemble the crossbow?

Cool stuff. ... Thanks!

Any type of hardwood would do except for the bow arms themselves. I'm still working out the dimension and material for my model at the moment.

will you also make the "tiger killing poison" to go with it?

Have you ever thought of making these on commission? I know I would pay (a reasonable price) for replicas of Chinese siege weapons!

People have made auto-crossbows before, you can google up some for examples.

and any thoughts of projects after this? Howabout a hampster powered trebuchet?
Or a multi-shot siege bow!

Ah... I just got back from HK 2 hours ago. I saw this beautifully crafted ancient chinese siege ladder at a heritage store at the Star Ferry terminal on Kowloon side. I was going to make one of those as Yun suggested but after seeing that, I think I'll just buy one. It looks absolutely beautiful. I'm flying back to HK next week again so I'll be going to take a look at it again and to see whatelse they have.

Commission? Nah, taking money will only kill the fun for me building stuff. Besides, I'm too lazy.

What's next? I don't know. I have yet to finish the Chu-ko-nu since I wasn't around over the weekend, but I'm kinda leaning to building the multi-bow siege crossbow after all that discussion on the other thread! Anyway, that'll have to wait until I'm done with the Chu-Ko-Nu. I'm going to go buy the material sometime this week. I need to settle back into the rhythm of things and clear work first. It's amazing how much work can pile when you're away even for just one day!

Tiger Killing poison??? ... How about the cobra stuf that you can import from India? ...

One more thing, you do mean a hamster not a hampter?? ...

The trigger is proving a ***** to make, especially since it's a small part made even smaller by having to scale it down even further for my model. It's got to be perfectly fitted into the hole and grooves for it to function well but just loose enough to move up and down easily when the crossbow is in operation.

The grooves/hole need to be done almost perfectly with all the edges sharp and vertical too.

I thought of modifying it to make it simpler but then abandoned that idea for historical accuracy. I'll just have to keep at it then. :-) I've modified the magazine a little bit to allow the trigger to be made just a little easier. I should have everything ready to cut and carve by tonight. I hope to finish up this Zhugenu before Sunday night or it'll be delayed another few days while I'm in HK.

Ok, I cheated a little in making the trigger. The whole assembly is supposed to be made out of a single piece of wood, but because of the small scale of this model, I don't dare try such minute chipping and carving on the slender pieces. So instead, I used two separate pieces and cut the half holes separately before joining the pieces together. This trigger should work but I'll only know for sure only when the whole chukonu is fully assembled. If it doesn't work, it's going to be a pain in the *** to correct since there is no way to get at the trigger after that.

A impressive feat of work.

Cardinal, thanks.

It's almost done except for the most important component, the actual bow itself. I'm still trying to find suitable material/pieces for it so I fear I won't finish it this week. I will complete the whole assembly except for the bow arms which will have to wait till I get back end of next week.

I hope you guys are having as much fun watching this as I am making it. My fingers are sore from having to stay steady while gripping tight enough to carve properly.

This is one challenging piece! It looks deceptively simple until you try and make one then you realise the precision required. I'm even more in awe of the original inventors of this thing now. And to think it was first built 2000 years ago. Dang, they were superb engineers!

Quite frankly, compared to the Mangonel and Ballista I built earlier, this zhugenu is much, much harder to build.

It's been slow going because I've had to reshape the magazine-mainbody interface yet again. It wasn't quite the right shape for the trigger to work while still remaining well within the movement groove.

My pull arm alignment is still a little off as the two pin joints are not exactly parallel. I'm working on getting them parallel at the moment or when pushing forward, the magazine will run off the grooves.

I've also hit a roadblock with the bow arms. My first one cracked in two during pretensioning. I'm using bamboo this time and am forcing it to creep with some long term stressing before trying to pretension the bow again. It's been a pain shaping both bow arms to match. (Can't have one side bending more than the other!)

the bow would seem to be the hardest part, as it either takes specific parts of specific wood, or composites

and composites take like a year to put together/dry

Yeah, but the challenge of forming the bow was a given when I first started this. What I didn't anticipate was the precision required in the magazine, the trigger and the corking mechanisms!

The bolts too had to be refitted to be just right so that they were loose enough to not get stuck but yet stack well enough to fall into place and fire smoothly.

But what really gets me is the fact that it's really easy to just slap a whole zhugenu together and it'll still work, kind of... but if you wanted one that works smoothly without jamming everytime you fire, and was powerful (ie. the bowstring is drawn back far enough to fire a bolt far) the angles have to be just right!

Here's my latest attempt. It snapped when I tried to get more oomp power out of it. Looks like I'll have to get a new bow... again. That was number 2.

It's done! Yay!!!!

I've finally completed it. It shoots bolts clear across the room. I doubt I can get up to the 7 bolts in 15 sec fire rate but it comes pretty close. I used a longer bowarm this time and ground the support pieces to follow the curvature of the bow in it's final position so that lessened the moment stresses a little more.

This is a close-up of the trigger being engaged.


Go check out the completed pictures!

ZhugeNu ca. 200 B.C. (1:2 scale) : Completed 10th May 2005.

'ZhugeNu ca. A.D. 11th century'

I thought you said this was built 2000 years ago?

Needham says that the Romans had big siege crossbows that could fire multiple bolts in quiet an engenious way, you might argue even more so than the chinese repeating crossbow and much earlier than 10cent too. Either way, China was still the first to use the crossbow and congradulations on your impressive model.

Well, yeah some historians believe the ZhugeNu was first invented in the Warring States period but I based my design on an 11th century model. I don't know if any images of a Zhugenu from the Warring States exists. It might look different from this 11th century model but the basic design was probably the same.

OK, I've changed it to ca. 200 B.C.

This is taken from Wikipedia on the Chu-ko-nu.

**********************************
History

Repeating crossbows have a long history, with the oldest accurate written knowledge dating to the Han dynasty (ca. 20-220 A.D.) in China. The Chinese repeating crossbow (诸葛弩, pinyin Zhū Gě nǔ, English transliteration: Chu-ko-nu or Zhuge-nu) is an extremely simple piece of equipment. It is claimed to have been invented by Chinese strategist Zhuge Liang (181-234 A.D.), which is arguable since the earliest drawings of the weapon have been found from the buried library of Chu, dating all the way back to 250 B.C. The Chinese repeating crossbow saw its last serious action in the China-Japan war of 1894-1895, where photographs show repeating crossbows as common weapons among Manchurian troops. The basic construction of this weapon has remained very much unchanged since its invention, making it one of the longest-lived mechanical weapons.

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My iron tipped bolts dipped in "tiger-killing poison".

Final picture (and the nicest one too I think :laughing: ) with 7 iron tipped bolts ready for loading into the magazine.

Question:

How long does it take for a complete newbie at woodworking to learn how to make crossbows and such? (Not Zhugenu, just normal crossbow)

Your weapons are really cool, and I am tempted to try them out, but I am quite busy myself and can't devote a lot of time to learning woodworking. (Though my dad can teach me a bit, I suppose)

Now I cannot make fun of Angry Boar in the RPG anymore because he'll just take out a machinegun crossbow and shoot me...
(heheheh)

Do you want to make any changes to the Lian Nu infantry I drew for Zhan Guo TW?

A crossbow might not be the best thing to start with since the bowarms are fairly difficult things to make. My zhugenu took 3 attempts to get right, the first 2 bows snapping when I tried to string them, and I wasn't even trying to make a recurve bow!

Try something simple. Woodworking is really simple. Just need patience to grind and plane and cut things until they fit.

I can help you with sketches I have and to help answer questions you might face when you're building your weapons. Try using soft woods first until you get the hang of woodwork. Soft woods are easy to cut and saw but they are obviously not as strong as harder woods. But since these are only models, they work fine with soft woods.

Get a good set of tools. The right tools make light work! A good "fine" saw, at least two sets of files in two different sizers, a simple carving tool kit with curved blades and straight blades, a nice sharp razor blade and lots of sandpaper! If you have one, a power drill does wonders too.

Let me know what you'd like to try building and I'll see if I can help.

Huh? You've been bullying Angry Boar?

*bang* *bang* *bang* *bang* *bang* *click click reload*
*bang* *bang* *bang* *piang!* "Oops, gun jammed!"
*knock* *knock* *tap* *tap* "Ah... ok."
*bang* *bang* *bang*


Ok I'll got take a look at them.

BTW, have you seen the warring states era siege crossbow I sketched for you? I don't think there is a picture of a warring states siege crossbow anywhere, at least I couldn't find any for you so I sketched one based on Joseph Needham's description in his book. It's very different from all those Song and Tang dynasty siege crossbows.

Jieming

Check out this cool picture of some Korean soldiers firing off repeater crossbows mounted on ships against the Japanese during the 1590s...

http://forums.swordforum.com/showthread.ph...&threadid=51592

Wow nice! They look very futuristic actually but they look a little too heavy for the archers to carry.

Where did those pictures come from? A recent painting? Or an old manuscript somewhere? The array of weapons depicted is impressive. Everythings from swords, zhugenus, spears, fire-spears to muskets!

Liang Jieming, just one question, how do you machine all the parts you need for the crossbows? Do you have a workshop (some simple machines and tools) or you find some other workshop and pay them to machine for you?

Huh? No all the parts are handmade. Just using simple tools... saw, file, blade, carving blade, plane, sandpaper, powerdrill!

Yeah, I'll probably start with something simple, like cabinet-making. Then I'll move on to cooler stuff like making weapons...

I'll probably have the space for such a project after we move into our bigger house in June. Approx how much will a decent set of tools cost?

Oh and how dangerous is this? My uncle lost 2` fingertips... and I'm scared I might too!

Where did those pictures come from? A recent painting? Or an old manuscript somewhere? The array of weapons depicted is impressive. Everythings from swords, zhugenus, spears, fire-spears to muskets!

[/quote]

The link does not work for me takes me to an error report. can someone help me.

the craftsmanship looks impressive so far

Hehehehe. Frankly, making a cabinet isn't easy... assuming you want to make one with perfect right angles and rigid enough to actually use.

The reason why I find making these weapons fairly simple is because I'm not held to rigid specifications! I could err a little in height or err in width and it'll still be ok since these ancient siege weapons weren't made that exactly anyway. If I tried making a model of a modern Lexus RX300 for example, a slight error in length would be very obvious to everyone here simply because every real Lexus RX300 is made to exacting proportions. So.... so long as I keep to roughly the right proportions as the pictures/sketches I'm ok!

A complete set of the basic tools shouldn't cost you more than a $20-30 except for the power drill. But get a good solid set. Don't go for the cheapest tools. Those blunt/break/loosen easily.

Dangerous? Of course. Anything to do with a blade or saw or power drill is dangerous. Just need to remember the golden rule... "Never cut/saw/drill towards yourself!" ie. keep in mind where the blade/drillbit might go after slicing through (or not slicing through if you miss) the wood.

Ah yes, I once brought a circular powerblade for a physics project, and the thing won't cut any wood. There goes the project .

RE: The link does not work for me takes me to an error report. can someone help me.

Link:
http://forums.swordforum.com/showthread.ph...&threadid=51591

around the time of Imjin war, Europeans were very much fond of the crossboat.

Crossboat, what is that?

Hey, the thought just struck me. I do believe this is the only working ZhugeNu (abeit an abreviated model) in Singapore!

Come to think of it, the XuanFeng sitting on my cabinet at home is probably the only working model of a Chinese XuanFeng in the world too! (assuming no museums in China have one! I sincerely doubt any western medieval enthusiast who's probably made lots of Roman ballistas and trebuchets has built anything from the far east too! )

Hey, LJM... Thomas Chen and I recently came across a pic of Zhuge Nu manufacture and use in the Ming dynasty Tiangong Kaiwu 《天工开物》 by Song Yingxing 宋应星:

Hey Yun, thanks. The ZhugeNu in the picture looks fairly similar to my model, but it seems to have a slightly elongated magazine/stock with the rounded cloud design on the underside of the stock. I would assume this is a heavier military version from the length of the magazine/stock. The increased length would mean longer bolts, longer draw and straighter trajectory though that's kinda pointless since you can't aim a zhugenu effectively anyway.

Another interesting thing is the fletched bolts. I wonder how they get fletched bolts into the magazine?

Yes, that's the same design I used. Yun's Ming design is more like this.

WOW! so talented.

Hmm, LiangJieming, if its not too much, you should create a Help Thread so that you can help the ones who are interested. wink wink.

my zhu-ge-nu is 1:1 scale. full size only the bolts are pencil thick, not sharpie thick.
i've started a production run of four more chukonus and the bows are still proving
to be the hardest part. i haven't found a good source for rawhide laces yet either.

the bolts will fire through a cardboard box at close range and the best range so far
has been 40 feet. the bow length is crucial. it needs to be right at the edge between
too big and broken. i want to try bolts with metal tips in the near future, too.

You've made one! Good! Please do post pictures here. Let's compare notes.

What's the scale of your zhugenu or did you build a lifesized replica?

I didn't know they even had machine crossbows.

Wow, thanks for the avi file! That looks impressive but I couldn't quite make out the bolts being fired. How well do they fire? Go range and penetration? What's the capacity of your magazine? What is your bow length? I couldn't tell from the avi.