The Armour Archive

A few years ago I made some pump action crossbows for SCA use. They don't really pump, they just have a curved metal bar like a "goatsfoot" that pivits through the stock body to allow easier draw, without letting your eyes leave the battlefield.

DUke Cuan of Atlantia asked me for the design and so here it is in rough sketch form. I will dig up one of the bows in a couple of days and take photos to make this drawing a little more comprehensible. If anyone knows Cuan I would appreciate it if you let him know this is here.

I've always wondered how that mechanism worked. Are yours the bows with the box magazines on top as well?

Johann ColdIron wrote:I've always wondered how that mechanism worked. Are yours the bows with the box magazines on top as well?

That one you are thinking of is a Chinese design. Very light draw weights in the originals, and I can't really imagine the box working well with SCA combat bolts...

I can't envision how Nissan's works from the diagram, but it doesn't fit with what I know of the Chinese design.

Kilkenny wrote:

Johann ColdIron wrote:I've always wondered how that mechanism worked. Are yours the bows with the box magazines on top as well?

That one you are thinking of is a Chinese design. Very light draw weights in the originals, and I can't really imagine the box working well with SCA combat bolts...

I can't envision how Nissan's works from the diagram, but it doesn't fit with what I know of the Chinese design.

Me neither.

I THINK it looks like some form of lever action.

By pushing the "lever" below the trigger down, it pulls the string back and cocks it into place. You then load a bolt and fire.

Johann ColdIron wrote:I've always wondered how that mechanism worked. Are yours the bows with the box magazines on top as well?

That's the Chinese Chu Ko Nu
http://www.arco-iris.com/George/chu-ko-nu.htm

For more inspiration take a look at this movie

http://www.ruestzeug-shop.de/repetierarmbrust-mk2-2.mov
(3,6mb works with QT and VLC)

It was build by a friend for Larp-Games.

some pictures

2.

3.

The photos clarify one thing greatly. What I read in the diagram as a single S curve lever is in fact one lever in two positions. That makes it much more understandable.

However, the photos leave me with a question, still. I don't see the string clearing the cocking lever - does it just slam the lever forward again on release ?

Put the lever back to position 1 prior to firing.

raito wrote:Put the lever back to position 1 prior to firing.

d'oh. too easy

thanks

So, you made one of these?

Did you work by ear, or did you have a plan that you used?

f

Are you talking to me?
Yes I have at this point made four of these things, two in rock maple and two in Padauk. If you get a big block of wood and nest them like yin yang you can get two stocks from one piece of wood. And I designed them so I don't know if that answers the qusetion of whether I had a plan.

Plan? I don't need no steenking plan.

Nissan Maxima wrote:Are you talking to me?
Yes I have at this point made four of these things, two in rock maple and two in Padauk. If you get a big block of wood and nest them like yin yang you can get two stocks from one piece of wood. And I designed them so I don't know if that answers the qusetion of whether I had a plan.

Plan? I don't need no steenking plan.

If I part out the job, would you correct it? I am thinking that this might not be above my skill level.

And where did you get your hardware? Is the cocking lever custom and the tickler fabbed, or are they stock items? Where did you get the prod?

What is the tubular bar in the pics (but not in the drawing) above the arrow slot for?

The drawing shows a ball on the base of the stock. This does not appear in the pictures (you just can't see the stock base). Is that added to balance weight? What did you use there? Is it steel, brass or wood?

Did you use a template to cut the routed sections?

Did you skip the routing entirely, and use a drill to do the inset sections?

Can this be made without a joiner or planer?

How did you attach the prod? It looks like you tied it on. Could the prod be bolted on? If not, what did you use to tie it on?

Is this based on a period design, or is it completely invented by you?

Is there some spring or cam to keep the lever out of the shooter's way when firing?

Did you include D rings for a sling?

How much strength does the lever take? Does it take a strong man? Could it be fired by a small woman? A ten year old child?

This is cool.

Thanks.

f

Q:If I part out the job, would you correct it? I am thinking that this might not be above my skill level.
A: I am not famialiar with your verb, but by context I take that to mean if you do part drawing will I tell you if you are right. Yes, of course.

Q: And where did you get your hardware? Is the cocking lever custom and the tickler fabbed, or are they stock items? Where did you get the prod?
A:The prod is from Alchem, all other parts from McMaster carr.

Q: What is the tubular bar in the pics (but not in the drawing) above the arrow slot for?
A: The tubular bar keeps the bolt in place when you are running around. It also allows you to fire the bow inverted. This is handy for standing under crenelations at the castle wall, lifting it upside down over your head and killing archers standing there.

Q: The drawing shows a ball on the base of the stock. This does not appear in the pictures (you just can't see the stock base). Is that added to balance weight? What did you use there? Is it steel, brass or wood?
A: I made a big bronze pommel for balance, and to smack people on the head with. (incidental contact)

Q: Did you use a template to cut the routed sections?
A: just a router table fence with a stop. I only used a router on the top channel.

Q:Did you skip the routing entirely, and use a drill to do the inset sections?
A: see above. but specifically, forstner bits and chisels.

Q:Can this be made without a joiner or planer?
A:Yes

Q:How did you attach the prod? It looks like you tied it on. Could the prod be bolted on? If not, what did you use to tie it on?
A: I cut a hole in the side of the stock and a prod shaped negative on the front. Then I ran about three yards of cheap plastic cord around in an attractive pattern. I took an iron and pressed it into the front to melt the shit out of it.

Q:Is this based on a period design, or is it completely invented by you?
A: it is my invention. I just wanted something that looked like a weapon, out of respect for the people I would be killing with it.

Q Is there some spring or cam to keep the lever out of the shooter's way when firing?
A: there was a simple coil spring at the pivot that returned it to the correct position but it got knocked off. It works without it but it is easy to make.

Q:Did you include D rings for a sling?
A: Due to the stupid rules for combat archery you have to remove it from the field before drawing a stick, so I didn't see the use in a sling.

Q:How much strength does the lever take? Does it take a strong man? Could it be fired by a small woman? A ten year old child?
A: The lever provides significant mechanical advantage. In my kingdom crossbows are 600 inch pounds at 12 inch draw. Unless he is a pussy a ten year old should be able to cock it.

Could the release pin spring be replaced with a metal bushing and a gravity recock?

I mean, could we do without that spring?

f

It could be, but why?
If the pin stays up you are holding a lever attached to 600 foot pounds of force with nowhere good to put it.

If you can have a bushing, putting in a 25 cent bushing sized spring greatly improves the ease of use. The spring also allows some niceties of tension between squeeeezing the trigger and jerking the trigger. I made one of these with rifle sights which was pretty accurate, till the rear sight got smashed to flinders.

Nissan Maxima wrote:It could be, but why?
If the pin stays up you are holding a lever attached to 600 foot pounds of force with nowhere good to put it.

If you can have a bushing, putting in a 25 cent bushing sized spring greatly improves the ease of use. The spring also allows some niceties of tension between squeeeezing the trigger and jerking the trigger. I made one of these with rifle sights which was pretty accurate, till the rear sight got smashed to flinders.

Well, mostly because I have never set a return spring, and I am not sure how to do it.

So, I will need a little help on that part.

f

This is tougher than I had anticipated.

And, I am pretty much guaranteed to look stupid in front of folks the know what they are doing.

I will have it finished tonight. Sorry for the delay.

I am not doing drawings. I am just doing a list of tools needed, a list of materials, and the steps in construction. If I can't do that, I can't do a job at all, but if you have the list of steps handy, you can measure how long it takes to do each step. This helps me a lot.

I know that I am getting part of it wrong. I have looked at making a crossbow before, but this is the first time I have actually really considered doing it.

f

I will take the firing mechanism on mine apart tonight and take pictures of all the parts for you. That should make it easier.

The only real critical part of this thing is the same for any crossbow and that is the wooden lip shape that holds the string in place at fulldraw rest. Every other thing can be pretty sloppy.

These are not complicated machines.

OK, here it is.

I know that to people who know what they are doing, this will look stupid.

There are some important things missing.

I don't know what the OD of thin walled 1/4" ID copper line is, for instance.

f

**********************************

Job worksheet, The Equalizer Crossbow, Dreadlord Nissan’s munitions grade, single shot, cho ko nu.
freiman the minstrel

Thursday, August 21, 2008

Materials list.
2 Pieces wood 1X4. Twenty four inch long
One Crossbow prod, available from Alchem
One Tubular bolt holder thingy, available from McMaster Carr
One Crossbow cocking lever, available from McMaster Carr
One Tickler, available from McMaster Carr
Six inches of ¼â€

I make the stocks in one piece so that pretty grain patterns are not inturupted by a glue line. (I am clearly not right in the head) I cut the inlets for the trigger mechanism with long drills and chisels. Your way will be waaaay easier.

Is there any hope of a good, precise isometric drawing of the void?

It would be a lot easier to make if could make a custom jig, and just keep the router up against the fence.

Also, I still have no clue of how you did your firing pin spring. I can think of a couple of ways to do it, but it would be nice to have a method that has already been tested.

Also, am I screwing up by the numbers on the steps in construction? I am pretty sure that I am making a mistake or two that people on the archive have already made.

f

The void

trigger mechanism

the firing pin is held to the trigger bar by a screw going though the trigger (sloppy clearance hole) into a drilled and tapped hole in the firing pin. 8/32 or 10/24 or something like that.

Place pin and spring into the appopriate holes and the put the trigger into the void and then put in the pivot pin that goes through the stock. Then screw the firing pin into the trigger from underneath. Loctite the fuck out of it.

Dreadlord Nissan,

Please check this.

The firing pin hole is a drilled in two sessions.

First, the firing pin hole (1/4") is drilled all the way through the stock. Then a slightly larger hole is drilled with the same center. The second hole stops short of going all the way through the wood. This leaves a lip of wood to hold the firing pin spring in place.

The firing pin is made from a round steel pin, about an inch and a half long, and about half an inch in diameter. The base has been drilled and tapped (probably about a quarter inch) and threaded with a tap set. Then a hole (bigger than 1/4 inch) is drilled at the perfect spot on the tickler. The stock is placed upside down, with the firing pin hole stopped somehow (ducktape?). The firing pin is placed in the firing pin hole. The firing pin spring is placed in it's own hole (around the firing pin). The tickler is put in place, but not fastened down. Then, the screw is set through the tickler and into the firing pin, holding everything in place. Locktite the fuck out of it. Then the tickler is riveted into it's final spot.

Have you ever had a problem with any of the holes (most especially the goatsfoot lever hole) "wallering out"? If you haven't, then I could do without sleeving those holes. That would cut the process time down a lot. I am thinking about Oak for this project. I also think you were right about the strap. That cuts the expense considerably

Do you have a cheaper source on Prods than fifty five dollars a shot that you could share?

Is there a cheaper or easier way to do the brass ball than a Hames topper? Could a regular shoulder stock be used there, if the (essentially) pistol grip shape was retained? This would cut ten bucks (at least) from the construction costs.

Also, you said you used rifle sights on yours. Is this difficult to install?

How much are strings? Where do you get them?

And are these parts from McMaster-Carr standard parts for some item, or do they need a little assembly/tweaking?

f

The firing pin hole is a drilled in two sessions, but it doesn't matter which you do first.

The firing pin is made from a round steel pin about a quarter of an inch in diameter. The length is depandant on stock design. Make it long and shorten it to fit. The base has been drilled and tapped (probably about a quarter inch) and threaded with a tap set. Then a hole (smaller than the screw head but bigger than the screw shaft) is drilled at the perfect spot on the tickler. The stock is placed upside down, with the firing pin hole stopped somehow (ducktape?). The firing pin is placed in the firing pin hole. The firing pin spring is placed in it's own hole (around the firing pin). The tickler is put in place, but not fastened down. Then, the screw is set through the tickler and into the firing pin, holding everything in place. Locktite the fuck out of it. Then the tickler is attached into it's final spot with a nut and bolt long enough to go through the stock side to side. countersinks accept the bolt head and nut

Use of hardwood should prevent holes from wallering out.

I do not have a cheaper source on Prods. But I have also not looked.

A regular shoulder stock could be used instead of a pommel.

I made a hinges brass plate with a slot and a brass ball on a stick kind of sight. I will draw a picture , but although useful this proved fragile in serious scraps.


Strings come with prods, buy extras.

The hardware is springs and rod for firing pins, triggers. tube for bolt retention and goatsfoot. taps screws bolts for pivots. (three, one for rigger, one for goatsfoot through stock and one for goatsfoot handle. This last is about 4 inches long and rests inside a tube that acts as a handle.)The rod for triggers and the tubes for bolt retention and goatsfeet need bending.

Joscha wrote:For more inspiration take a look at this movie

http://www.ruestzeug-shop.de/repetierarmbrust-mk2-2.mov
(3,6mb works with QT and VLC)

It was build by a friend for Larp-Games.

Trouble is this design doesn't appear to be accurate at all. There doesn't seem to be a way to hold the bolt in the locked position long enough to stop and aim the thing.

Of course that probably isn't what it was designed for to begin with. For high volume of fire into a tight formation where you are almost guaranteed to hit SOMEBODY, this would be the cats ass.

Joscha wrote:For more inspiration take a look at this movie

http://www.ruestzeug-shop.de/repetierarmbrust-mk2-2.mov
(3,6mb works with QT and VLC)

It was build by a friend for Larp-Games.

Joscha,

Thank you for this excellent video. The Cho Ko Nu in the video is really cool.

I would love to see that weapon and handle it. I think that I might be able to make one.

Is that man in Deutshland?

Ich Woehne in Deutschland.

f

Mac Thamhais wrote:Trouble is this design doesn't appear to be accurate at all. There doesn't seem to be a way to hold the bolt in the locked position long enough to stop and aim the thing.

Of course that probably isn't what it was designed for to begin with. For high volume of fire into a tight formation where you are almost guaranteed to hit SOMEBODY, this would be the cats ass.

Although it's certainly not as nice looking as some of the ones I have seen, the design is essentially correct from my understanding.

These crossbows were more like the machine guns of their time than the sniper rifle. Drop a lot of fire towards the enemy, but not very accurately.

Give 100 of your guys clips of 10 or so bolts and see how fast they can fire their 1000 bolts into the enemy formation. Accuracy ceases to be the necessity here.

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

Ogedei.

Dreadlord Nissan,

Thanks, I will try to have streamlined job worksheet by Tuesday morning your time.

Robyn said today that she is pretty certain that she can find prods from a job shop in The East cheaper than fifty five per prod.

For now, thanks.

Wanna do a web tutorial?

f

Ogedei wrote:SNIP
Give 100 of your guys clips of 10 or so bolts and see how fast they can fire their 1000 bolts into the enemy formation. Accuracy ceases to be the necessity here.
SNIP

Valid point.

Attached is a more detailed plan of the front including the recess for the prod and the arrow channel.


Isn't this a web tutorial?