Instructables

How to Build a Crossbow

Picture of How to Build a Crossbow

The crossbow is one of those inventions that changed history. Prior to its invention, an archer might train for years before developed the strength and proficiency to be an effective warrior. With the crossbow a modicum of training could turn even the meanest peasant into a soldier.  Additionally, through the use of mechanical cocking mechanisms, brute strength was no longer a limiting factor.

All that aside, here's my attempt to design and build a crossbow.

Please note, this should not be attempted by anyone, it can kill you, your dog, your ... etc. etc.


 
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Step 1: The prod, or bow.

Picture of The prod, or bow.
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Fortuitously, I need not replicate this instructable. All you need are the dimensions.

The overall length is 50" with a width of 2 1/2" tapering to 1/2" at either end.  The thickness is 7/16"s.

The nocks, are like the nocks I used previously, how ever instead of tying them on, I used hardwood pins.

Please note, one edge of the bow is kept straight.

I did back the bow, with denim. I simply layed down a coat of Titebond  and then a piece of denim which I rolled into the glue with a dowel, similarly to using a rolling pin.



Step 2: The Stock

Picture of The Stock
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The Stock was whipped up in ProE, it's really just two rectangles, one 3x20 and one 5.5x14.5 offset and joined with a spline to make it "pretty".

So grab the dimensions off the picture and cut out two from3/4 inch ply (it was what was handy)

Once the two pieces are cut, they are screwed together with wood screws, since they will need to be disassembled several times.

Now's as good a time as any to use your jointer to even out the top edges of the two stock pieces, if you don't have a jointer (I don't). screw the stock to a board and just use your tablesaw.  But those top edges must be flat and level.




woodstuffs5 months ago

What kind of wood did you use for the prod?

starseeker12 months ago
How can someone make one of these without all the power tools you used and the knowledge to use those tools? Seems like this is a project to show off skills rather than help someone get ready for a disaster. Geez
Well, if you have no skills or knowledge, you can't. Simple as that.
could this be resized with a pistol grip to make a hand crossbow? What other alterations would be needed?
SirBobert1 year ago
What type of arrows did you use? And does the crossbow end up having the 50lb load that the Pyramid Bow had since its the same design? Thanks.
M3G1 year ago
Awesome design!
travw2 years ago
First off, great job. I was having trouble with trigger ideas.

Secondly, what bolts are you using? The bamboo arrows? Have you considered modifying it for use with ball bearings? I think it would be quite doable, and most likely could be undone as well.
zelback1 travw1 year ago
The trouble with the ball bearing idea is that it would have to be weighted directly in proportion to the strength of the crossbow. I am an archery hunter, and I can often be seen at the practice range trying to put six arrows within an inch wide circle from thirty yards. The relevance of this is as follows. By far, the worst injury I have ever seen in a range accident occurred when a guy about three stalls down shattered the crossbow he was using, injuring him, and mortally wounding his spotter. The ambulance came and I watched him get wheeled out on a stretcher with a half-inch thick peice of fiberglass sticking out of his kidney. The reason his crossbow exploded was that he had tried to shoot a bolt that was way too light for the strength of his bow. The result was that all the force that built up upon pulling the trigger rebounded and destroyed the structural integrety of the limbs, which still left so much pent up force that the bow, well, basically exploded. If you were to shoot a ball bearing out of a crossbow and either misjudged the needed weight, or, as seems quite likely due to the nature of the projectile, the ball bearing slipped, you could wind up in a hospital bed, or worse. I would advise you to put some serious thought into this. I later learned that the man who had been spotting for the crossbow-man had bled out on the way to the hospital. I would absolutely hate to think of that happening to somebody else.
MTChar2 years ago
Hey can you please tell us what type of wood you would use for the prod?
Awsome instructable though!
chromestone2 years ago
so we r not suppose to attempt this, it seems you are giving us the instructions to attempt this but at the same time a little unclear the instructions maybe a video of the crossbow in action?
In other words he posted this simply for the sake of knowledge. That and if it kills someone it isn't his fault.
well i wanna build one
mutual wants bro..
FairQueen12 years ago
Crossbows are a great alternative weapon. They certainly have a long history of efficiency as a weapon. This is a great guide to building one.

Recently I've also gotten into air rifles. Not as ancient but much safer than regular guns. There are competitions around the world.
http://www.airarmsairrifles.com
"Recently I've also gotten into air rifles. Not as ancient but much safer than regular guns. "
I've been into air rifles and pistols for over 40 ears, and "much safer" is not too accurate, depending. I've got an air rifle in 9mm and in .45 caliber that would not really be considered "safer" than a firearm. They're used for medium to even large game hunting where firearm ownership is not practical, or illegal for one reason or another.
l8nite2 years ago
I acquired a well abused crossbow recently and of course it needed a new bow. I searched for hours online to ind a crossbow bow with no luck but I did find out that when it was made my crossbow was rather good. I also found out by searching in the parts list that a bow is actually called a limber (who knew?) and is readily available for a nominal fee. Your crossbow is gorgeous, have you been able to use it since you wrote the "ible"?
red-king3 years ago
Great stuff. too bad crossbows are illegal in the place I live in...
Ahhh come on they can't find out who fired it :P
lol
morris102902 years ago
Wow very nice x-bow i actually tried to build my own pellet gun similar to the one here http://ak74airsoft.com/TAPCO-AK47-WOODEN-STOCK-SET-BRWN-LAM-TINTIM06000BRWN.htm but you could barely feel the pellet hit you even from close range... and that's saying a lot considering most ak47 airsoft guns hit HARD. Now if only I could build a penny shooter -.-
nieks3 years ago
Very nice instructable, Allthough I think for my first real crossbow build I wouldn't go for the rolling nut design, because if has a reasonable margin of error. I would choose the notch lock design. It is a bit less pretty, and isn't as smooth as a rolling nut can be, but it almost fool-proof (quite usfull if you are an inexperienced woodworker like me :p )
christpher3 years ago
what do i us to billd the front pes
skimmo3 years ago
this is a great explanation of the nut tigger
Anonbonbon3 years ago
I'm suprised no one has asked this, and maybe it is due to the fact that they can find it, but I can't seem to see where you say what kind of wood the prod is.

May I "prod" at you to reveal what wood it is?

...wow, that was a horrible pun. =_=
Tool Using Animal (author)  Anonbonbon3 years ago
It's red oak, just check out my longbow instructable for details.
Colonel883 years ago
Was the trigger design possibly influenced by...

http://www.pyramydair.com/blog/images/10_11_07_crossbow_trigger.jpg

Also, eventually the sear will wear off, as the trigger holder thing will break it off.
Tool Using Animal (author)  Colonel883 years ago
They cribbed that from here, my original source.  And yes, they'll wear, but are simple to reproduce.

It's the standard design, been in use for a thousand years

seolfor3 years ago
You can also make one using a leaf spring from an automobile. Use the shortest length, and cut it to the same dimensions for your prod. Cut steel rod for the rolling nut, and cut plate steel for the trigger. Braided/twisted steel cable is then us used for the string. Yes, you have to do a lot of hammering to get the leaf flat. However, that was how my dad taught me to make my first one. It had a little over 100 lbs of pull. We used a scrap piece of steel strip to make the bolt holder. Just passing along the info.
seolfor3 years ago
Very nice. I haven't made one of these in almost 2 decades. Thank you very much for sharing. I may have to see what I have available in my scrap pile. :)
yztay3 years ago
I liked your trigger design ;)
Kaiven3 years ago
I saw this and was immediately happy. A sear system crossbow... finally the perfect doable trigger design!
rimar20003 years ago
Very good work, I want to do one like this!!
tfultsucf3 years ago
Well done sir, well done. I'm not going to lie, this really makes me want to make my own = successful instructable.