/diy/ - Do It Yourself

wont work, not going to bother telling you why because its fucking obvious

>>596953
Can you propose a way that will work?

>>596952
sorry for some typos I'm not sure where "box " came from but it's supposed to mean bow so yeah.

>>596955
no, because google exists, dumb fuck

My mother and her cousin made a crossbow with a leaf sring when they were young. No one's ever taken the umbrella branche of the tree in the back yard.

>>596953
>>596964
Dry your eyes sweetheart, your mascara is running.

>>596952
>what would be a good, cheap material for the bow part?
Leaf from a car suspension.

Probably too powerful for what you're doing but this recommendation is old school, from way before the Internet.

>>597190
>Leaf from a car suspension.
i know people usually suggest this, and I've never tried it,,,,, but I don't think it would work.

for example: at local farm stores they sell replacement leaf springs for small trailers. the SMALLEST ones are rated for 1000 lbs,,, and a car weighs much more than that.
now,,,,,,, the mini-trailer packs are 3 leaves. you could take the pack apart and just use the largest leaf (the one with the eyes in the ends) but I still think it would be about a 500-lb pull bow.

what I would suggest as something easy to make, is not to use a spring-bow at all. use a rigid bow (a piece of 2 x 4 wood with a big hook in each end) and use surgical tubing as part of the "string" instead. (pic related) All the parts are at the local hardware store and don't cost much, and you can use as many loops of surgical tubing as you want--to make the bow weight as high or as low as you want.

>>597221
>but I don't think it would work.
It must work, I've seen pics of the finished article. I'll try and find a printed reference if you're interested, either one of my survival books or The Crossbow has plans and instructions.

It makes a very powerful crossbow, and you do need a cranequin or something similar to span it.

>>597190
>>597221
>>597377
interesting, I think my frame could handle the pressure from the car suspension leaf. if I were to use that, what medium would the string have to be? nylon?

>>596952
Well, if there is any available to you i would go with either bamboo or river cane. check this out for info, just got to mod things a bit I guess.

http://sensiblesurvival.org/2012/03/24/build-a-bamboo-survival-bow-in-30-minutes/

>>597496
Leaf springs necessitate a ratchet and mechanical advantage/gears to use. They are usually used to launch gliders.

I hate to be a buyfag, but ...
http://www.amazon.com/Performance-Crossbow-Metal-Replacement-Prod/dp/B009XXGA18
$5.50 + shipping

Sometimes they go on sale. I almost bought an 80lb prod for $1, and then regretted missing that deal.

Unfortunately there isn't a DIY alternative that's as cheap and functional as just buying one.

>>597496
I don't know enough to give you concrete advice but I'm pretty sure nylon is slightly too elastic. The Crowwbow book I'm sure will list a natural fibre because of its age but this may actually be the best type of thing for the job regardless. One of the survivalist books I have gives instructions on how to make it up yourself from linen thread, but you'd need the full instructions and pics to be able to follow through, since you need to form the loops at either end it's not exactly simple.

Anyway, Google should provide answers. Probably should have been your first port of call anyway.

>>597221
Further to my reply above, seeing it in print might convince you:
http://www.vintageprojects.com/archery/crossbow-leaf-spring.pdf

Cutting down the profile, so there's less steel there, may be the key factor.

>>596952
A bow string can be made out of a taunt spool of sewing thread. Basically a thread that has no give so it doesn't stretch when you string it. Look up how to make a bow string jig and then just use thread instead of dracon string. Though dracon string is faily cheap so you might as well buy some. If you have some bees wax chap stick you can use that for your string. As for making a crossbow I don't know much but if you want a bow make a wooden riser and then heat pvc and taper it for the limbs. It's fairly cheap and you only need a rasp and sand paper.

>Pic related it my wooden riser

Make it out of pvc.
http://lmgtfy.com/?q=PVC+crossbow

>>596952
Just make it out of Oak

Stop sign pole is not spring steel, when you cock it back, its going to bend and stay bent.

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

Watch backyard boyer's channel. Seems like a good crossbow he makes out of pvc.

>>596952
NO WEAPONS.

>>599855
It's obvious the op will be tying a rope to the bow, thus creating a grappling gun.

>>596952
I suggest you buyfag the crossbow prod (bow) because it's very easy to hurt yourself with homemade steel prod if you do not have a basic understanding of metals, heat treating, and engineering.

>have some sort of smaller coaster inside that to hold the bolt and push it forward
Why not just have the string push the bolt? The coaster is unnecessary mass that decreases the energy efficiency of the crossbow.

>the chord would be parachord
You generally want the prod to do the stretching / bending, not the string. If the string is stretching, it is decreasing energy efficiency.

>also trigger/cocking mechanism thoughts would be graciously accepted.
Attached is a picture of the crossbow I am working on. It's a 16th century design. Requires some kind of metal shop to build though. This website helps a lot:
http://crossbow.wikia.com/wiki/Crossbow_Building_Wiki

>>597221
>just use the largest leaf (the one with the eyes in the ends) but I still think it would be about a 500-lb pull bow.
You can decrease the pull by making the prod's height shorter. However, you don't want the height to be the same as the thickness otherwise the twist itself instead of bending.

>>599855
You are reading challenged anon. READ THE REST OF THE SENTENCE FFS!

>>597190
>>597221
>>597496
>>597377
Yo fuckards.

>>596952
PVC.