Build your own crossbow


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alemonkey
December 30, 2007, 11:27 PM
Anyone ever build their own crossbow? Not a modern one, but a medieval style armor-puncher. I've been eyeing site for a while, and one of these days I want to order some parts and go at it:
http://www.alcheminc.com/crossbow.html

I'm a sucker for anything historically accurate, and I've seen a couple of authentic reproductions. Neat stuff.

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mole
December 31, 2007, 06:04 PM
I have considered it in the past and may still make one. You should be able to make one yourself without having to order the metal parts. I perfer a simple wooden bow myself.

alemonkey
December 31, 2007, 07:27 PM
I've thought about building one with a wooden prod, too. It would be neat to make a laminate one.

Cannonball888
December 31, 2007, 08:17 PM
You want an armour-puncher? In one of the old Popular Mechanics books it shows how to make a crossbow out of an automobile leaf spring. Probably takes a winch to cock it.

RyanM
December 31, 2007, 09:02 PM
I've always wanted to make one of these.

http://www.koreanarchery.org/rcb/index.html

The first ever "assault weapon!" I've even heard that some were made with two magazine stacks, so it would fire two bolts simultaneously. I figure it wouldn't be too hard to make a toggle switch that can set it to fire from one or the other magazine, or both. With 12 bolts in each one, you'd have up to 24 shots on tap, with hip accuracy. May also be possible to monkey with the cocking system so that, optionally, the handle can remain cocked and an actual trigger squeezed.

Timthinker
December 31, 2007, 11:17 PM
If you wish to consult a book on crossbow history and construction, please read The Book of the Crossbow by Ralph Payne-Gallwey. This work is a century old, so you will learn techniques that may not be discussed by modern crossbow constructionists. Still, this work may provide some interesting information to consider.


Timthinker

denster
January 1, 2008, 12:48 AM
Actually just finished one today. Using Alchem's prod and parts. Very high quality parts at a very reasonable price. I used the claplock mechanism and bowirons to hold the prod to the tiller. Turned out very nice and throws a one ounce bolt with authority.

TAB
January 1, 2008, 12:49 AM
I built a bolista in HS for a project... ended up being way too powerful for the class...

230RN
January 1, 2008, 07:39 PM
I was going to start a new thread with these questions, but since this one's fairly recent, I figure you posters might know.

I recently picked up a hand crossbow. MTech DX-80.

Never had one before, and I know nothing about them. Just always wanted one, if only to hang on the wall.

But just for grins I'd like to play with it indoors at a range of about thirty feet. (Do not want the neighbors to spot it.)

(1) What kind of backstop might be effective? Seems to me a carton of newpapers might not stop a bolt with the regular target piles unless they are really tightly packed, which would make them hard to recover.

(2) I don't really think I need the 80 lb. draw weight. If I were to get a slightly longer string (say an inch or two) to reduce the weight, would there be any negative effects?

mole
January 1, 2008, 08:45 PM
I don't have a crossbow, so I can't comment about it's penetration. Even my 50# selfbow will penetrate a 2x4 using field points, so you better have too much of a backstop rather too little of one.

230RN
January 2, 2008, 12:33 AM
Even my 50# selfbow will penetrate a 2x4 using field points, so you better have too much of a backstop rather too little of one.

I kind of figured it would penetrate like mad. My son had a hand crossbow many years ago and he said if you hit a tree, you could not get the bolt out without destroying it.

But how much is too little? Are there other options besides a carton full of newspapers? These bolts weigh about 145 grains and I reckon going less than 300 f/s.

I used to be pretty good with recurves of aboout 50 lbs (this was before compound bows were invented) but what with arthritis and a shattered left collarbone, I doubt I could draw a 35 lb target bow any more.

Roswell 1847
January 2, 2008, 01:20 AM
Remember that if you use a Steel Prod its wise to cover the prod with a thick wrapping of leather or canvas.
If a Steel prod breaks on firing the splinters can kill you, also the broken end can swing back at you like a sword.

Some Swiss and German target crossbows used a bolt with grooves like negative rifling down the length of the bolt. The Steel prod had a ratchet shaped hole in the center. As the bolt went through the hole it spun like a rifle bullet.
Could be thats where the idea for rifling gun barrels came from.

Those target bolts had threaded heads and a spanner that fit the nock area.
When fired at a wooden target you couldn't pull it out so using the spanner you unscrewed the bolt from the wood.

230RN
January 2, 2008, 11:48 AM
Roswell 1847 remarked:

Remember that if you use a Steel Prod its wise to cover the prod with a thick wrapping of leather or canvas.
If a Steel prod breaks on firing the splinters can kill you, also the broken end can swing back at you like a sword.


Gee, maybe it would be a good idea to lengthen the string as I asked about above.

Still need to know about indoor backstops, though.

alemonkey
January 2, 2008, 08:07 PM
Actually just finished one today. Using Alchem's prod and parts. Very high quality parts at a very reasonable price. I used the claplock mechanism and bowirons to hold the prod to the tiller. Turned out very nice and throws a one ounce bolt with authority.

oooh....any pictures? What draw weight did you go with?

Remember that if you use a Steel Prod its wise to cover the prod with a thick wrapping of leather or canvas.
If a Steel prod breaks on firing the splinters can kill you, also the broken end can swing back at you like a sword.

The alchem prods say they come covered with rubber tubing, but leather would look a lot nicer.

Chipperman
January 3, 2008, 10:54 AM
I made one when I was about 12. I used a leaf spring from a trailor. The bow itself was about right the right tension. The problem I had was in the simple trigger mechanism I made. I was not able to fire it well b/c the tension from the bow prevented the sear from being pulled down.

I was still proud to have done as much as I did at 12 without any help or diagrams.

230RN
January 3, 2008, 03:10 PM
I also built one when I was a kid. Used a broomhandle as a frame and a sear that was a piece of wood stuck up through a hole in the broomstick connected to a trigger that ran parallel to the frame and connected to the sear by a hunk of string. Had about the same problem, but it was operable. Sorta.

I used a shaved-down hunk of maple from the tree out back for the bow. Broke several of them on cocking before I got one to work. Sorta.

On my modern one, the string is held by a step in the frame of the crossbow and the "sear" merely pushes the string out of the step.

I wish I'd'a thought of that when I was a kid.

Isn't anyone going to tell me what might a suitable backstop for indoor use of a hand-held crossbow of 80lb? (See post # 9.)

mole
January 3, 2008, 05:33 PM
Personally I think that shooting it inside is a bad idea. Once you get something strong enough to stop the bolt I assume that it'll be hard getting it out anyway. Sometimes I have to split the wood I'm using as a target to get my arrows out.

denster
January 3, 2008, 06:20 PM
Here is a picture of the one I built.

denster
January 3, 2008, 06:23 PM
Forgot to add. 155lb draw at 8inches. Shoots a 435gr bolt at 212fps. Takes a lot to stop them I use the dense foam targets designed for compound and crossbows.

alemonkey
January 3, 2008, 07:14 PM
Beautiful work, you did a really nice job on that.

mole
January 3, 2008, 08:29 PM
I too really like the looks of that. What kind of string is that? Do you mind telling how much it cost?

Oldnamvet
January 3, 2008, 09:17 PM
You jogged my distant memory so I had to check. I have some of the PM Do-It-Yourself Encyclopedia books (1955) and one of them has plans for a crossbow made with either a lemonwood bow or an automotive leaf spring.
They showed a cocking lever being used with the leaf spring bow since it had a greater than 100 lb. pull. The string used for that one was a 5/32" dia. steel cable.:what: Imagine what would happen if that broke.

denster
January 3, 2008, 09:50 PM
Thanks for the compliments. Cost wise the parts were about $130. I used the plans on alchem's website and bought the prod (bow) bow irons, wedge pack, stirrup, tickkler (trigger) and claplock mechanism from him. Really reasonable price for very high quality parts. The bubinga for the tiller (stock) I got from one of the dealers on eBay.

The string is B50 dacron got that from alchem also.

alemonkey
January 4, 2008, 12:09 PM
Is there an advantage to using the claplock vs. the roller nut for the string release?

230RN
January 4, 2008, 03:21 PM
mole said:
Personally I think that shooting it inside is a bad idea. Once you get something strong enough to stop the bolt I assume that it'll be hard getting it out anyway. Sometimes I have to split the wood I'm using as a target to get my arrows out.

I kind of figured that, but I thought maybe some folks with some experience in crossbows might have a whizbang idea about it.

Oh, well. I'll let it go.

What about lengthening the string 1" - 2" to reduce the draw weight? Are there any unforeseen problems in that?

denster
January 4, 2008, 05:29 PM
No real shooting advantage to the claplock over the roller lock. The claplock is considerably easier to inlet and is easier to get the correct sear engagement.

carpettbaggerr
January 16, 2008, 12:48 AM
I wouldn't shoot an 80 lb crossbow indoors, if you miss, it's gonna go through your walls, and maybe your neighbor's (or neighbors :uhoh:)as well.

For a target, I'd use one of these : http://www.cabelas.com/cabelas/en/templates/pod/standard-pod.jsp?_DARGS=/cabelas/en/common/catalog/pod-link.jsp_A&_DAV=&rid=&indexId=cat600346&navAction=push&masterpathid=&navCount=5&parentType=index&parentId=cat600346&id=0039350

madmike
May 29, 2009, 12:21 AM
Sorry for the thread resurrection. Sheesh, crossbows have suffered the same exaggeration as "assault weapons."

Crossbows have LESS range and penetration than high end longbows or recurves. The energy is a function of pressure (draw weight), distance, and limb length. 60# over 28" of recurve is a lot more than 150# over 8" of crossbow. Draw a real longbow in the 100# and up range and crossbows aren't the slightest bit competitive.

They are easier to aim, though, and really cool. I was searching for plans to turn a prod into one for my daughter for SCA use.

And no, prods will not shatter with enough power to kill you. Nor is wrapping required any more, nor was it done in period. Yes, I'm sure there's an exception or two, but it was never a big deal.

KenWP
May 29, 2009, 05:08 PM
The yards used jeep springs to great affect so it has to be possible to make a crossbow at home.

jakeiscrazy
November 14, 2009, 11:56 PM
I'm gonna be working on a crossbow from a truck leaf spring. I plan to use a 2x6 as a stock. Then Dremeling a wheel lock out some barstock metal. I have built a couple with pvc before but this will be a new league for me. Any solid advice would be a huge help. BTW I am going to taper the spring as to lessen the power. If I don't almost kill myself I'll post a picture. (-;

tomahawk74
November 16, 2009, 03:03 PM
never made a crossbow, but have made different kinds of spearguns.. do alot of snorkeling in the summer.

madmike
December 20, 2009, 02:39 AM
http://crossbowhunters.com/_sgt/m3_1.htm

If you want a commercial fiberglass prod to go with this design, I sell them.

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