How to Make a Repeating Crossbow

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How to Make a Repeating Crossbow by Jaycub on June 6, 2013

Table of Contents How to Make a Repeating Crossbow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Intro: How to Make a Repeating Crossbow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Step 1: Gather Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3

Step 2: Look at the Plans: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4

Step 3: Cut the Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4

Step 4: The Arrow Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6

Step 5: The Lever . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8

Step 6: The Stock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8

Step 7: The Bow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Step 8: The Ammo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Step 9: Finish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Related Instructables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Advertisements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

http://www.instructables.com/id/How-to-Make-a-Repeating-Crossbow/

Intro: How to Make a Repeating Crossbow This instructable will show you how to make a repeating crossbow, also called a "Zhuge nu" or "chu ko nu." This is a type of crossbow invented in China thousands of years ago that is like an ancient submachine gun. Just push the lever forward and back and it will fire a steady stream of arrows until the magazine is empty. It doesn't have that much power or accuracy compaired to a normal crossbow but it has a fast firing rate and is easy to use. I have included an instructional video and a step-by-step photo instructable. If you have any questions or any of these instructions are unclear to you please let me know and I will try to clearify. CONTESTS: I think this instructable meets the requirements of the Epilog challenge and the Launch it! contest so I am entering it in those.

http://www.instructables.com/id/How-to-Make-a-Repeating-Crossbow/

Image Notes 1. All of the completed main parts.

Step 1: Gather Materials You will need: -A 2x4 in any type of wood, prefer few defects of course (at least 27" long) -1/2" Sch 40 PVC pipe (at least 22" long) -Red oak 1x2 (53" or more, other hardwoods are OK) -A 1/2" x 5.5" x 48" poplar board -3/8" poplar dowels (recommend three 48" dowels) -5/16" dowel (at least 10") -Larger dowel, 3/4" to 1" diameter (at least 6" long) -Glue -white glue -epoxy -hot glue stick -String (I used 9/16" venetian blind chord, it is mixed polymers) -Two 1/4-20 bolts, 3" long, with nuts. -Wood screws (at least 6, ones that are 2"-3" long would be great) OPTIONAL: -Wood stain -Spray on clear coat -Brown spray paint -1.5" wide hinge -1.5" wide by 1/4" thick oak or poplar board (10")

All of that is available at a hardware store, mine was from Lowes mostly.

Image Notes 1. Douglas Fir 2x4 2. 1/2" Sch 40 PVC Pipe 3. Red Oak 1x2

http://www.instructables.com/id/How-to-Make-a-Repeating-Crossbow/

4. 3" long 1/4-20 bolts with nuts 5. String, 9/16" Venetian Blind Chord 6. 1/2" x 5.5" x 48" Poplar Board 7. 3/8" Dowels 8. 3/4" to 1" Dowel 9. Wood Screws

Step 2: Look at the Plans: These pictures show all the dimensions and materials for the parts that need to be cut out and drilled. Mark these shapes onto your materials. Details about which material each part should be made from, hole sizes, etc, are written on the plans. I don't think any more instruction is needed for this step unless the plans are unclear to you (they look fine to me but let me know if there is an issue).

Step 3: Cut the Parts Once you have all your cuts and drill places marked, cut everything out. A band saw and a power drill (prefer a drill press) would be very helpful for this. Also cut the 3/8" dowels into 8" pieces. Aside from the sanding this is most of the "work" of this project.

http://www.instructables.com/id/How-to-Make-a-Repeating-Crossbow/

Image Notes 1. Everything you need to cut and drill.

Image Notes 1. I recommend using a bandsaw if possible.

Image Notes 1. Magazine parts

Image Notes 1. Lever parts

Image Notes 1. PVC

Image Notes 1. Large diameter dowel 2. This also needs to be drilled, see plans

http://www.instructables.com/id/How-to-Make-a-Repeating-Crossbow/

Image Notes 1. Stock cut from 2x4

Image Notes 1. 3/8" dowel for "bolts" (arrows).

Step 4: The Arrow Box Get all the magazine parts (on the plans they are labeled magazine walls, magazine spacers, and arrow trough. For this step you will also need white glue, clamps (or weights), and idealy a dremmel tool or similar rotary sanding tool (but a round file, knife, or even coarse sand paper can work). Sand the bottom edge of the front magazine spacer ("L" shaped one) so it is rounded concave. Then line up the magazine walls and spacers and glue them together (see pictures for position if it is not obvious to you). Clamp these together or stack weights on them while the glue dries. Once it is dry, sand it so all the layers line up smoothly without rough or uneven edges. Then mark the lines shown in picture 6 on the arrow trough. There is one line going crossways on the board 12" back from the front (the end without the 1/4" hole is the front), and a line down the center from the front all the way back to the 12" line. Carve grooves along those lines with a dremmel sanding wheel. The front-to-back line is the trough the arrows ride in, and the side to side line is a notch that catches the bow string. Glue the arrow trough on to the bottom of the magazine walls. Cut or sand a 5/16 or 3/8" dowel in half lengthwise, so it is flat on one side. Cut about 10" of it and glue that 10" piece to the bottom of the arrow trough. Position it so it starts at the front edge of the arrow trough, is running lengthwise centered side to side.

Image Notes 1. These are the magazine walls and spacers

http://www.instructables.com/id/How-to-Make-a-Repeating-Crossbow/

Image Notes 1. Sand or file a rounded shape into the bottom of the front "L" shaped spacer

Image Notes 1. Glue the layers together, make sure it's lined up well

Image Notes 1. Cut a slot for the string into the bottom of the magazine. Dimensions shown on the plans.

Image Notes 1. This is the oak 1x2 labeled "arrow trough" on the plans. 2. 12" back from the front, mark a side to side line 3. Mark a line down the center from the front all the way to the 12" line

Image Notes 1. Carve a groove down the lengthwise line. The arrow will ride in this.

Image Notes 1. Cut a notch at the 12" back line

http://www.instructables.com/id/How-to-Make-a-Repeating-Crossbow/

Image Notes 1. Glue the arrow trough onto the magazine

Step 5: The Lever This is very simple just glue and screw the lever handle on to the lever arms. White glue or epoxy are both good for this. I chose to round the other end of the lever arms for asthetics.

Image Notes 1. This is very simple. Just line the lever parts up like this, glue and screw them together 2. Round off this end if you think that looks better (I did).

Image Notes 1. Lever parts

Step 6: The Stock Once you have cut it out as shown on the plan, all you need to do to this part is grind a 14" long groove into the top like on the arrow trough. The dowel on the bottom of the magazine will ride in this groove that you grind into the stock. Then screw and epoxy the 6" long piece of 7/8" dowel on to the back of the stock.

http://www.instructables.com/id/How-to-Make-a-Repeating-Crossbow/

Image Notes 1. Stock cut from 2x4

Image Notes 1. Mark a line down the center of the stock from the front back to 14"

Image Notes 1. Carve a groove down that line the same way you did on the arrow trough

Image Notes 1. Mark the notch for the bow 3" back and 1" deep/wide as shown on th plans

Image Notes 1. Cut out the notch

Image Notes 1. The finished stock, sanded smooth and corners rounded.

http://www.instructables.com/id/How-to-Make-a-Repeating-Crossbow/

Image Notes 1. This screws on to the back of the stock

Step 7: The Bow Now you need the 22" long piece of 1/2" sch 40 pvc pipe with the markings on it as shown on the plans. We are going to heat it until it gets soft** then press it between two 2x4 boards. 5/8" thick wood spacers should be placed between the 2x4s alongside the pvc pipe to control the final thickness of the pressed pipe. Use clamps to push the 2x4s firmly together. Once you have done that squirt some hot glue into both ends of the pipe, this will be a filler. Heat the 3" long sections on both ends of the pipe (one at a time) and press them as shown in picture 6. The end of the pipe should be completely closed after this pressing. Be sure that when you press it the pipe is rotated so that the part that was wider from being pressed between the 2x4s is the part that becomes flat. Heat the center 1.5" wide section of the pipe and bend the bow limbs (each half of the pipe) slightly back and upward. Then cut / sand the now flattened limb tips into a roughly parabolic shape and smooth out the edges with sand paper. File a notch into the limb tips for the string to catch on (called knocks). Drill holes and screw the bow into the notch in the stock. For the string, just tie a loop in each end and make it so it looks just on the long side of the right length. Tie knots in the string to shorten it one at a time. Keep putting it on the bow to check if it's tight.

**To heat the pipe I am using a propane heater but you can use a torch, a heat gun, an electric or gas stovetop, camp fire, bbq, etc. Try to move the pipe around a lot in the heat to keep from scorching it. It will become soft and flexible.

Image Notes 1. This is the 22" section of PVC pipe with marks on it as shown on the plans 2. The pipe and 5/8" think boards are resting on a piece of 2x4 3. These two boards on either side of the pipe are 5/8 inch thick and will act as spacer to control the thickness of the pipe when we press it 4. This picture shows a basic mold that we will use to press the PVC pipe. It is two large boards (2x4s) that the pipe is sandwiched in between, with 5/8" thick strips of wood a spacers. When the PVC is heated in will become pliable and will accept the change in thickness. 5. This picture shows a basic mold that we will use to press the PVC pipe. It is two large boards (2x4s) that the pipe is sandwiched in between, with 5/8" thick

http://www.instructables.com/id/How-to-Make-a-Repeating-Crossbow/

Image Notes 1. Propane heater 2. The pipe 3. Heating the PVC pipe. Move it around a lot in the heat and try not to scorch it. It will become soft.

strips of wood as spacers. When the PVC is heated in will become pliable and will accept the change in thickness.

Image Notes 1. Clamp it betwen two boards with the 5/8" spacers as in the first picture. Make sure it is straight!

Image Notes 1. Thake it out of the mold. It will now be partly flattened.

Image Notes 1. Put some hot glue into both ends 2. Hot glue stick

Image Notes 1. Heat the 3" sections at either end of the pipe and clamp them like this

http://www.instructables.com/id/How-to-Make-a-Repeating-Crossbow/

Image Notes 1. Heat the center 1.5" section. It will turn back to it's round shape when softened. Then bend the bow back a little (called adding "deflex"). 2. The flattened limb tips

Image Notes 1. You want the bend in the center of the bow to be slightly upward as well as back. You can see about how much in this picture.

Image Notes 1. Cut / sand / grind the limb tips to a roughly parabolic shape. And round off the edges.

Image Notes 1. File a notch into the limb tips for the string to hook on

Image Notes 1. Drill holes and screw the completed bow in to the stock in the notch

Image Notes 1. For the string, just tie a loop in each end and make it so it looks just on the long side of the right length. Tie knots iin the string to shorten it one at a time. Keep putting it on the bow to check if it's tight. 2. For the string, just tie a loop in each end and make it so it looks just on the long side of the right length. Tie knots iin the string to shorten it one at a time. Keep putting it on the bow to check if it's tight.

Step 8: The Ammo Get your 8" long pieces of 3/8' dowel, they will be made into the bolts (arrows). Sand or file a + shaped notch into one end of each dowel. This will help the string catch it. Then drill a hole in the other end of each one (drill press is much nicer for this than a hand drill). The exact size of the hole will depend on your arrow points. The arrow point is suppose to glue in to this hole. I used a 13/64" bit for mine. After you have the holes drilled epoxy in the arrow points. You may want to sand the area where dowel and point meet after gluing depending on how well the sizes match up.

http://www.instructables.com/id/How-to-Make-a-Repeating-Crossbow/

Image Notes 1. Get the 8" long 3/8" dowels. They fit in the magazine.

Image Notes 1. Sand a shaped notch into one end of each dowel

Image Notes 1. This is what the notch should look like. It helps catch the string.

Image Notes 1. Drill a hole into the other end. Make it large enought to fit an arrow point in.

Image Notes 1. Glue a steel arrow point in the hole. 2. I got these arrow points on ebay. They are 75 grain, 11/32 inch diameter. Heavier ones like 100-125 grain may be better.

http://www.instructables.com/id/How-to-Make-a-Repeating-Crossbow/

Step 9: Finish Assemble the completed parts and test it: Set the magazine on the stock, slip the lever over that and line up the holes, and put the bolts through (you don't need to put on the nuts right now). Then string the bow and push the lever forward until it catches in the notch in the arrow trough. Pull the lever back. You will immediately notice that it does NOT fire. Don't worry I haven't mislead you. Let the lever forward and push the string out of the notch with your thumbs. Now all you need to do to finish the mechanism is to sand the front edges of the notch (the one the string catches in) to smooth and round it off. Keep doing the test with the lever until you get it sanded smooth enough to where it does fire. Now it's done! At this point I chose to stain and clearcoat the wood parts and paint the bow brown. Obviously you can decorate yours however you want. After you have done whatever surface treatments you are going to do, it is a good idea to put vegitable oil on the center of the bow string to help it slide easier and not wear through as fast.

Image Notes 1. All of the completed main parts.

Image Notes 1. Screw on the bow for the final time. You may want to epoxy it too.

Image Notes 1. Set on the magazine

Image Notes 1. Screw in the nuts as far as possible. 2. Slip the lever on and line up the holes. Put the 3" bolts through. Screw in the nuts as far as possible, it will be tight.

http://www.instructables.com/id/How-to-Make-a-Repeating-Crossbow/

Image Notes 1. Put on the string

http://www.instructables.com/id/How-to-Make-a-Repeating-Crossbow/

Image Notes 1. This is the optional magazine lid. No instructions for this are realy needed. It's just a piece of wood with a hinge glued to it.

Related Instructables

first knex chinese repeater crossbow (chuko-nu) EVER! (Photos) by necropolian

Knex Chu-ko-nu or repeating crossbow (Photos) by bryoda

K'nex Chu-konu/Repeating Crossbow by bryoda

Knex Chu Ko Nu (Photos) by Oceanous

how to choose the right pistol crossbow by uniFREAK134

Twin Crossbow Introduction by sphsengineering

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Comments 35 comments Add Comment

jsmit3 says:

Jul 2, 2013. 11:23 AM REPLY

I would suggest making the bow out of wood it may be harder but its more powerful

Jason the marksman says:

Mar 26, 2014. 1:55 AM REPLY

it's more powerful if you use metal bar so it will be "repeating arbalest" instead of "repeating crossbow"

Jaycub says:

Jul 2, 2013. 11:49 AM REPLY I used to use wood bows when i sold these as kits but it is easier to make it out of PVC and the statement that "its more powerful" is incorrect. This PVC bow is more powerful and smaller that the wood bows that were on the kits.

Jason the marksman says:

Mar 16, 2014. 7:01 AM REPLY

Hard to make.but it's worth of it

Jaycub says:

Mar 17, 2014. 9:59 PM REPLY

Did you make it?

ubicity says:

Dec 5, 2013. 2:26 PM REPLY

great stuff

paracordperson550 says:

Nov 10, 2013. 12:58 PM REPLY

awesome

jhowie103 says:

Oct 15, 2013. 5:42 PM REPLY

Very impressed

Ridach says:

Sep 16, 2013. 6:42 PM REPLY

there is no measurements for the handle, or did I just miss it

Jaycub says:

Sep 16, 2013. 11:31 PM REPLY It is there, in one of the lower pictures. You have to click on the images of the plans to enlarge them and you will find it in the image that shows "oak 1x2s."

jsmit3 says:

Jul 3, 2013. 7:08 PM REPLY

Also in the instruction it doesnt tell how to release the string

Jaycub says:

Jul 4, 2013. 8:46 AM REPLY If you are talking about the thing that puches the string out of the notch, then you are saying things where you don't know what you are talking about again. If you read the last step I describe how sanding the front edge of the notch will make the string slip off at the right time. I have made several of these things and the string-pushing block is realy not needed.

http://www.instructables.com/id/How-to-Make-a-Repeating-Crossbow/

jsmit3 says:

Jul 2, 2013. 11:26 AM REPLY

The bow part rather than pvc

Derpthetroll says:

Jun 22, 2013. 4:59 PM REPLY

OMG!!! I saw a repeating crossbow in jack the giant slayer but it had two barrels and left me very confused

antibobthebuilder says:

Jun 18, 2013. 7:54 PM REPLY

COOL

Kid Ninja says:

Jun 13, 2013. 2:01 PM REPLY

Just a note, the magazine walls are 18 inches long, not 15. Just a typo. :)

Kid Ninja says:

Jun 13, 2013. 2:30 PM REPLY

Also, for the top half of the magazine walls, mine's not coming out to 14.5 inches. Is there an error?

Kid Ninja says:

Jun 13, 2013. 5:00 PM REPLY Okay, as far as I can tell, the 9.5 inch measurement should actually be 12.5 inches, and the 14.5 inch measurement should be 17.5 inches. That allows the bottom and top edges to be the same size, and allows for the same angle on the spacer and the magazine walls.

Jaycub says:

Jun 13, 2013. 5:22 PM REPLY I don't know how you are coming up with that. The angle is the same on the back spacer and on the back of the walls if you follow the plans. On the spacer and on the walss, the slant at the back goes down 3.5" and over to the right 5." I did just find one error which might be the one throwing you off, the 12" for the part cut into the bottom of the magazine should be 9." Hope that helps. I will upload the corrected image.

Kid Ninja says:

Jun 13, 2013. 5:28 PM REPLY Yep, that was it. The 12 inch measurement threw me off, and changed the angle of the wall. Thanks! Sorry to bother you.

Jaycub says:

Jun 13, 2013. 11:58 PM REPLY

OK cool sorry about that!

Jaycub says:

Jun 13, 2013. 5:17 PM REPLY

What do you mean? The will come out however you draw them. I don't think there is any error on the plans.

Jaycub says:

Jun 13, 2013. 5:15 PM REPLY

No, they realy are 15."

resistanceisfutileiflessthan1ohm says:

Jun 12, 2013. 11:10 AM REPLY very very cool. i saw one of these in museum once and tried to build one myself years ago. this is excellent work, i would however advise creating a quick diagram showing how it works so others can copy the mechanism with slightly differently sized or shaped parts. i am voting for it.

Jaycub says:

Jun 12, 2013. 2:30 PM REPLY Thanks! That is a good idea to show the mechanism. Right now I'm thinking that it simple enough that they will understand just by looking at the pictures of the completed thing. But maybe I'll draw a diagram.

bensmiller02 says:

Jun 12, 2013. 11:51 AM REPLY really this type of design could be applied to modren crossbows im sure or even just modified with a different lever design to allow you to pull a stronger bow back im sure its all been done before but we have sense lost or forgotten the technology for more "advanced" technology. but whats more advanced than being able to make your ammo in the field with a sharp knife or rock even lol

onemoroni1 says:

Jun 11, 2013. 8:27 AM REPLY Outstanding! I voted too. It gets my brain working on a more powerful design with a spring loaded clip that feeds from under the crossbow.

http://www.instructables.com/id/How-to-Make-a-Repeating-Crossbow/

Jaycub says:

Jun 11, 2013. 10:07 AM REPLY Cool I would love to see pictures of that if you do it! Of course, if you are looking for a more powerful weapon my brain goes toward entirely different technologies...

troopersmachine says:

Jun 10, 2013. 8:55 PM REPLY

Very Cool, you have my votes.

Jaycub says:

Jun 10, 2013. 11:00 PM REPLY

Yay! thanks!

ewijaya5 says:

Jun 10, 2013. 9:01 PM REPLY

AWESOME!!!!!! that was very good

beefeny12347 says:

Jun 10, 2013. 6:12 PM REPLY

awesome

rimar2000 says:

Jun 10, 2013. 3:18 PM REPLY

Impressive work! Thanks for the subtitles in the video.

Jaycub says:

Jun 10, 2013. 5:36 PM REPLY

Thank you, and thanks for that patch! Yes the video wouldn't have been too helpful without the subtitles.

Ranie-K says: Great photos!

http://www.instructables.com/id/How-to-Make-a-Repeating-Crossbow/

Jun 10, 2013. 12:13 PM REPLY