Instructables

What should I use for crossbow limbs?

I'm thinking of making a small crossbow, but I'm not sure what to make to limbs out of. Right now I'm either thinking some sort of wood, not sure what type, or fibreglass. Any ideas?

kevinhannan3 years ago
My main worry here is to match the string with the bow material. Each can break under pressure and give you an unrecoverable injury. You would also need a jig to safely test the bow under pressure to make sure it does not snap under you.

However, don't let that put you off; it sounds like a great project but you should be aware that accidents don't usually ask if you mind losing a digit or two, or an eye. Just be careful.

That said, second-user crossbows can be had for pocket-money change. Examine it carefully and get the seller to fire off a few bolts themsleves first. If it is faulty, they may refuse for some reason and you should walk away.

However, you might try a bamboo and synthetic tennis string combo. I say bamboo, but not bamboo sticks. The bamboo where it is formed for pliability and strength and can be routed to shape and drilled. You can also use multiple lines of string.

A great project, let us know how you get on!
rouge.renard (author)  kevinhannan3 years ago
It would be unpleasant if something broke.

Having a jig to test the limbs on is a good idea. I should be able to make something.

I have thought of buying one, but I want to try making it.

I was thinking of getting a string made out of Dacron.

I’ll tell you how it goes.
It could be much more than unpleasant if the bow broke. Even a longbow snapping can be dangerous, which is why bows should be inspected for developing stress fractures periodically (and are always inspected before competitions). There's a lot of energy in a bow.

For what it's worth, the crossbow prods (proper term, might help you websearch) I've seen have mostly been steel.
rouge.renard (author)  orksecurity3 years ago

I have a slight tendency to understate things. I do a little archery and I know how dangerous a bow can be if it is not properly taken care of and I’m aware how high the forces can be.

Prod, limbs and lath are all acceptable terms. Prod and lath tend to be used more when talking about older crossbows, whereas limbs is more often use when talking about modern crossbows.

Thanks. I’ll think about that too.
Well, then, surely the deciding factor must be how much time and money you are prepared to spend on the project...

For example, you will be aware of increasingly expensive materials that can provide strength with flexibillity against the cost of machining such a part. Unless, of course, you want a dirt-cheap and effective solution - in which case your question would be slightly different?

Given your additional comments, what are your priorities in this project?

(Soz for the spelling, my disability is playing up a bit and I really can't be troubled for grammatical accuracy this late at night ;-)
rouge.renard (author)  kevinhannan3 years ago
I’m willing to spend a fair amount of time on this however, I would prefer to keep the cost down as much as possible without compromising quality.

I’m not sure I understand what you are asking.

Trying to get as much power as I can reasonably expect in a pistol crossbow.
Thanks for your patience. It's worth reminding folks, even if you're already clueful -- the next reader might not be.
rickharris3 years ago
rouge.renard (author)  rickharris3 years ago
Thanks, they look pretty helpful.
rickharris3 years ago
>>>>>look right>>>>>>>>>

lots of advice.

What properties do you want the bow to have -

What materials have those properties?

What build advice is available on the web.
+1. Already well documented here and elsewhere.

If you want SERIOUS advice on building and using a crossbow, get in touch with the Society for Creative Anachronism. They have folks who are experts in historical construction techniques and materials, and folks who are experts in turning a crossbow (and training a crossbowman) for extreme accuracy. There may well be a group in your area whom you could work with to learn both.
rouge.renard (author)  orksecurity3 years ago
I would have thought so but, I haven’t had any luck.

Thanks, I’ll check it out.
rouge.renard (author)  rickharris3 years ago
What properties do you want the bow to have?
I want the bow to be as small as possible, around the size of a pistol crossbow, so that I can pack it away easily. I’m thinking of having the limbs fold to the side when not in use, so each limb would be around a foot long. That being said I would like it to be able to have as much power as possible.

What materials have those properties?
I’m not sure.

What build advice is available on the web?
Although I’ve found a lot of advice on how to make bows, almost all of it is for making an English long bow or something similar.