Sbravati Homemade Crossbows and Rope Cocking Aid

[mintwithahole]

Im going to copy this design for my 150lb crossbow. Thanks for posting.

[pwnage696969]

hey

VERRRYYYYYYYYY NICELY DONE, can you please make a video on how to attatch the stings?

Thank you

[vinosd773]

where did you salvage the hooks from?? DO NOT USE BUNGIE CORD HOOKS YOUVE BEEN WARNED!!

[bsbravati]

@vinosd773 ddude, they are regular pulleys, probably to be used in constructions sites or in a roof clothesline. Of course nobody would use bungie cord hooks, afterall you need a pulley!

[ZehWallace]

very nicely built crossbows! i am thinking about building one myself, but i am not sure wich kind of pulleys to use. you have any recommendations? thanks in advance =).

btw, i am from brazil too =P. im only writing in english coz of possible other viewers wondering about the pulleys too.

[shervin814]

how much did this all cost you?

[bsbravati]

@shervin814 dude, I had to pay only for the fiberglass, the string and some screws, which sum less than 30 dollars... the other parts come from scrap material from the workshop where I was working in the crossbow

[lockpick92]

moving to the fibre glass bow has meant you dont have a tapering bow which means you dont have a nice arc like you did on ur last bow but thats just a small criticism and also I dont understand why you moved to exocentric pulleys, I under stand their use on compound bows, ie the string becomes much lighter at the end of the draw so that it is comfortable to hold but why use them on a crossbow???

[bsbravati]

@lockpick92 in bows the excentric pulleys also increase a lot of the strenght in the way to the full draw, having a massive drop by the end, right?

in crossbows, as the trigger holds the string, obviusly, I projected the pulley so as it cocked just before that drop, hence, I have more strenght derivered to the bolt during the shot, thus increasing it's aceleration, so as to have a higher final speed...

about the bow, fiberglass has a higher response and lower density, so it's better than steel.

[zprify]

Where did u get the plans for building it. What books should I look for to create one?

[bsbravati]

@zprify no plans, no blueprints man, did it all by myself, improved it from the mistakes I did in the first one

[bsbravati]

@borat6363 If well calculatated, eccentric pulleys will increase the string acceleration during the shot! Cams work similar to that, but they are pretty expensive...

[borat6363]

Great crossbow. Why did you move from centric to eccentric pulleys?

[bsbravati]

@borat6363 eccentric pulleys will increase the string acceleration during the shot! Cams work similar to that, but they are pretty expensive... Pulleys can be easily turned

[Dracoaliamin]

What did you make the black bendy part of the bow from?

[bsbravati]

@Dracoaliamin the piece that attaches the bow to the body?

it is common steel, maybe 1020

the bow itself is a kombi van leaf spring, steel proper for bending

[renrifle]

How were you able to get the steel leaf spring of a car? i've been trying for ages to find one here in the philippines. Did you order it of some auto parts store or did you jus find in a junk shop or scrap metal shop

[bsbravati]

@renrifle man, i found them in a scrap metal shop, these leaf springs are pretty common here in brazil... If you don't find kombi's, you can look for the beetle's, jeep, fiat 147, and so on...

good luck! =)

[mrkiky]

do you have a link to a good readup on compound mechanics?

[bsbravati]

@mrkiky dude, I don't have! And if you find, tell me... figured out the eccentric pulley, the angles and measures by myself

[renanpires92]

puta bom demais cara ! parabens meesmo ;D

tenho algumas duvidas : D

que corda da pra usar ae cara ? e qual tipo de metal usado ae ?

responde as perguntas pra mim ae ! to afim de fazer um ;D

vlws bro ! : D

[bsbravati]

@renanpires92 cara usei poliester encerado e trançado flemish, nao é metal nao, é umas varetas e fibra de vidro, use 4 de 350x11 mm vai da massa =)

boa sorte!

[magic3658]

best ever seen

[preyingforburglars]

might make a big self cocking one to turn onto a repeater c my vid

[preyingforburglars]

did u makk those stocks

[bsbravati]

yeah! both stocks...

jigsaw, saw, rasp, drill, a looot of sandpaper and sweat

[serby21]

Hey, are there any devices which allow you to cock crossbows without the use of your foot? I would like to know so I don't have to stand up when firing a crossbow prone.

[erez0ack]

hey man!

great vid. ans realy good crossbows. i realy liked it.

i'm planing on building a fiberglass compound one, like yours. i can get those sticks, thats not a problem, but i wanted 2 know what's the diameter of your fiberglass sticks? and another question- how fragile are those sticks? did you broke your bow or something?

i realy hope you'll answer. thanks.

[bsbravati]

I'd tell you to use sth around 8 - 11 mm diameter sticks, not even a mm more! Not saying that you won't pull, but they'll brake... I used 14mm and they've kinda broken in the axis of the fibers, a real shame, I should change them but have no time...

They're far more fragile than steel springs, but it's possible to use them, with more caution of course...

Hope I did answer ur question...

ask here if u need sth else ;)

good luck!

[erez0ack]

great. thanks.

which material you think is better- the spring steel or two (thin of course) sticks of fiberglass? i know the classic material for bows is fiberglass, but i am a bit worried about its fragility. any way, thank you for you answer.

[bsbravati]

honestly?

steel!

ahahahahha fiberglass cannot be heated, it's a little worrying if it falls down and hits a hard floor, plus that those sticks are not proper for that, they're the same material of fishing rods, but massive... That is, the chance of screwing it all is a lot bigger =P

even more if it's your 1st crossbow, or 2nd, like this one and I screwed it =(

so work with steel, cheaper and more resistant!

good luck, and as soon as you have it built and a video posted, do tell me... =D

[erez0ack]

ok. sounds reasonable. i guess i can get a car's spring steel. thanks for ur answers and honesty of course. (;

erez.

[arturbazz]

hey guy! i'm brazilian! I liked it and want to make one. but i need more details to make! you have? photos, drawings, links? Excellent work! Thanks

[bsbravati]

eaee rapaz, sou brasileiro também!

tens orkut?

procura la a comunidade, Crossbow - Besta - Balestra, tem muita coisa pra te ajudar... =D

[mixiplik]

hello

i´m martin from argentina, and i make a medieval model of crossbow a time ago. I want make a compound crossbow, but, i´m not sure how can design. i´m interesting in the correct measures, also in the design of trigger, Gun-sight and the pulleys. maybe later i load a video of my crossbow.

tank you

( my english isn´t the best, sorry)

[rinzegewoon]

hey i wanna make a crossbow to, but i wan't it to be powerfull which mean getting a steel or fibreglas spring and i have seen your inpressive videos of your crossbows and i was wandering were did you get the springbit for your crossbow ? is the metal one an section off a car leaf spring (i thing thats to strong to excually use but i have no clue what so ever). sorry for my bad english, hope you understand :)

[bsbravati]

hello man...

so, in the steel prod crossbow, it's a kombi van (from volkswagen, very old car) spring steel... i used one and a half spring, the wider measuring 63cm and the smaller 30 cm...

in this one shown on the video I used fiberglass sticks, which showed themselves really strong, thou far more fragile... =D

[vinnay]

whats the wings of the bolt made of.

[bsbravati]

you can make the fletching with PET, EVA, bicicle tire...

[vinnay]

what string do u use ?

[bsbravati]

in the cocking aid, regular string, sold by the pound... in the crossbow Polyester flemish strings that I made

[vinnay]

u should make turoil plz