/diy/ - Do It Yourself

you cant use raw wood

it needs to be dried. unless the most you hope from it is to be able to launch rubber bands

>>625289
vintageprojects dot com have great plans for repeating crossbow

for the tools, I'd recommend just basic tools, nothing specific

>>625290
It is dried. I meant raw as in still just a branch.

>>625337
You generally don't make stuff like this from just "a branch". While the wood may have been taken from a tree limb it's usually quite a bit larger than the finished piece and you cut it back a lot to get to the finished dimensions.

Also if you're just hoping to use a random branch you don't know until you get into it whether it is useable, how the grain runs, whether are there are any flaws or cracks that would preclude it being suitable for your project etc.

There's a hell of a lot of force exerted on the main member of a crowwbow during spanning and when it's holding tension before firing, you don't want that to catastrophically fail on you!

Also tools will depend on exactly how much work you're comfortable doing by hand. A minimal list for some woodworkers for making a crossbow would include a bandsaw ($$$), although you can do it entirely by hand tools of course.

I guess a minimal tool list would be:
>tenon saw
>chisels or carving chisels
>steel rule or other measuring device
>pencil
>lots of abrasive paper

For a general idea look into bowmaking. The same rules apply for the bow of your crossbow. You put very much strain into a pretty short piece of wood, so you will not get away with many things that would not be a problem with a normal bow.

semi-related: in other threads people have talked about using part of a car leaf spring to make a crossbow.
I haven't seen one made, but most car springs I've seen were pretty big-- maybe ~3" wide and 1/4" thick--and I'd think it would end up being a 500-lb-pull bow.
Even the smaller leaf springs used on cheaper trailers are still pretty big. They're like 2" wide and 3/16" thick.

.....however....

OLD volkswagen beetles used really thin & small front torsion springs on their front axles. (pic related, CIP1 sells VW parts) the torsion spring is actually a spring *pack*, of a few thin strips that can be separated (or combined). The outer diameter of the whole spring pack is only about 1.25 inches, and they are about 48 inches wide. If you wanted to make a bow and wanted to use spring steel leafs, this would be one possible source. They are already pretty thin and narrow to begin with.

CIP1 sells new torsion spring packs for $60 each, but there is also lots of beetles sitting in salvage yards all over much of the world.

>>625289
Not a bow/crossbow expert here. But you'll need to split the bow limbs rather than cutting them to shape. Cutting wood, even approximately along the grain still leaves some grain stopping midway. Which is where the crack will start.

>>625864
>semi-related: in other threads people have talked about using part of a car leaf spring to make a crossbow.
>I haven't seen one made, but most car springs I've seen were pretty big-- maybe ~3" wide and 1/4" thick--and I'd think it would end up being a 500-lb-pull bow.
>Even the smaller leaf springs used on cheaper trailers are still pretty big. They're like 2" wide and 3/16" thick.
More than one guide I've read has specifically called for a truck leaf spring FYI.

Anyway, the way this is workable is the one thing people never seem to think of: you're not using the full width of the leaf. They're cut down, and tapered towards each end, which significantly lowers their strength.

>>625961
>>625864
Yo

>>625864
Leaf springs from larger cars are frakking HEAVY. Try a small riceburner type car.

>>625843
>The same rules apply for the bow of your crossbow. You put very much strain into a pretty short piece of wood, so you will not get away with many things that would not be a problem with a normal bow.
on the contrary, short limbs that do not have to travel very far can hold a tremendous amount of energy.

>>625429
I would like to correct you sorta on these tool requirements.. more of thing's that will help if at all.

coping saw. for find detail and curves.

some form of drill.

Tenon Saw.

a sharp knife. [actually ALL your tools should be beyond shaving sharp. including your chisels and any hand planes.]

Hand plane.

also, maybe a hack saw if you're gonna make anything with metal.

also a dremel for smoothing and cutting small metal bits [triggers and shit]

ALSO! go on a popular knife forum, look up some people/vendors that sell knife stock, look for spring steel, ask them if they could temper and shit for you.. explain what you're doing..

another alternative. is to buy fiberglass matting online, and make your own fiberglass limbs..

Speaking of that also. Tightbond III [3] and wood veneer glued together would be equal to fiberglass pretty much..

that's all I got at the moment OP.

>>625994

>on the contrary, short limbs that do not have to travel very far can hold a tremendous amount of energy.

Exactly. They hold a lot of energy. And there is a lot of strain in them.

For example (an existing crossbow that I measured): The bow is 32" long, it is pulled 20 inches.

That is a lot of power in not much material, assuming we are talking "real" draw weights here. A bow that is 70" long and pulled 28" will put the strain into a much longer bow, don't you agree?

>>625988
>Leaf springs from larger cars are frakking HEAVY. Try a small riceburner type car.

you mean the type of car that's used coil springs for only the last 25 years or so?

good luck with that one...

just use an old car leaf spring for the bow.

http://www.vintageprojects.com/archery/cross-bow-leaf-spring.html

>>626295
32" wood bow pulled to 20" is pushing it, to put it mildly.
One reason is that in a crossbow design you are dealing with a bow meant to be held at full draw for a relatively long period of time. This will induce a huge set in the limbs, making them inefficent when compared to a longbow. BUT it takes a huge strain of of the limbs.
A full sized wooden bow should have as little possible set, if possible it should even have a backset.
backing up a little, set is the degree a bow stays bent after being unstrung
A short bow that is designed to have a set near to what it is fully strung is relieved greatly under full draw strain compared to a strait bow or reflexed bow.
This is also how some people like the Mojave indians made functional bows out of shitty woods. They deflexed the bows to reduce strain.
there is lot of factors how much strain a bow can withstand aside from length/draw distance.
Limb width
unstrung profile ( what I was just trying to explain )
wood type, moisture content
proper tiller
string material
backing
front limb profile
and more that I cannot think of right now.
Bowyery is witchery and science, both.

>>626735

Using deflexed arms surely limits stress. But it also reduces draw weight and power of the bow!

If you want to have a crossbow with serious draw weights, you put vast stress on the very short bow, there is no way around that!
If you deflex this bow, you will have to draw it farther to get to the desired power. Deflexing it is no magic way to limit stress while having power.

Having set and a deflex design are different things. Set means overstrained (and potentially damaged) limbs. Deflex design means the wood did have a deflex growth or that you heat bended it in.

Proper tiller and "dry wood" are a given anyway.

I kepp to my opinion in this matter:

High draw weight and short bow limbs means high stress on the bow. Which in turn means high requirements to worksmanship and material.

Most pickup trucks still have leaf spring rear suspensions. And most utility trailers too.
You would need to use a hand-saw to cut them down tho, because if you used any kind of power saw (I would guess that) the heat from power cutting could ruin the spring's temper.

Farm stores also sell small leaf springs for trailers (pic related). They already come in *almost* the perfect shape you'd want, but you'd have to drill some holes and run some bolts through the leaf ends (the green arrows) to keep the thing together, since you would be bending it the opposite direction of normal (pic related). And drilling those holes would be a battle if you had no drill press,,,, but anyway.

The reason I know about the Beetle front-end springs is because I'm fixing up an old Beetle, and had to replace the whole front end due to axle beam rust. I was just going to offer the old axle for free on craigslist but maybe if I get bored I will pull the spring packs out to see what they look like.

A cutting disk in an angle grinder or circular saw will slice through a leaf spring.
Let it float and cut freely. The thin discs intended for 6" angle grinders work best because they have the narrowest therefor fastest cut.

>>626888
deflexing does not reduce draw weight, it reduces cast.
>Deflexing it is no magic way to limit stress while having power
Of course not, it is a way to make a wood bow functional when using extremely short, skinny, or high draw weight design or inferior materials.
>Set means overstrained (and potentially damaged) limbs
you should say excessive set, because every single piece of wood that is bent will take some degree of set. A well designed wood bow will take a couple inches normaly. If it takes a negligible set then most likely it is over built and inefficent.
but anyway me origional point was that you can make a super high weight short bow simply by limiting the draw distance.

>>627252


>deflexing does not reduce draw weight, it reduces cast.

Don't know what cast exactly means.

But let me be more precise: If you deflex a bow, it will have less draw weight in contrast to a straight or reflex limb if you pull it the same distance, and we both can agree that neither the crossbow length nor the arms of the bow user are unlimited.

>Of course not, it is a way to make a wood bow functional when using extremely short, skinny, or high draw weight design or inferior materials.

I still do not understand how you want to pull of a crossbow in the 100lbs plus (!) range with this technique and additionally get away with bad material and/or tiller...

>you should say excessive set, because every single piece of wood that is bent will take some degree of set. A well designed wood bow will take a couple inches normaly.

I agree completely. Of course there will be slight set - I thought of something different than the one or two inches that are normal.

>>625289
Why not just get a recurve bow? Safer for obvious reasons.

>>625289
You'd likely need to reinforce the wood arms with fiberglass or something for stability, but there are a lot of good guides out there. I'd make it out of a plank or two, and you'd probably need at the least a drill, a saw, and something to shape it, but if you want to streamline the process and make it pretty, you'd want some sandpaper, rasps, files, planers, a drill press, clamps, etc.

>>625291
hey man, I checked this website out. all manner of thing he>>625291
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chhers mate

>>625986
Yo