Crossbows - Everything about Building, Modding, and Using your Crossbow Gear

Latest topics

» Nut from a pool que ball?
by drawknife Sun Jun 17, 2018 5:29 am

» my composite crossbow lath project
by stuckinthemud1 Fri Jun 15, 2018 6:07 am

» Trouble with my Gafa
by drawknife Fri Jun 15, 2018 2:56 am

» Do all triggers Have claws - what types and claw or no claw
by globalmark Thu Jun 14, 2018 12:19 am

» For Sale: Masai Crossbow
by TonyU Mon Jun 11, 2018 1:15 pm

» Medieval composite bows
by juanjo Fri Jun 08, 2018 5:10 am

» yew and sinew prod help needed
by stuckinthemud1 Thu Jun 07, 2018 1:34 am

» Small gothic crossbow (with wooden lever)
by OrienM Fri Jun 01, 2018 10:35 am

» Binding on the stirrup
by Geezer Sat May 26, 2018 7:26 am

» horn inlay and veneer
by OrienM Thu May 24, 2018 8:44 pm

» Presentation
by c sitas Wed May 23, 2018 4:31 pm

» My latest crossbow
by drawknife Tue May 22, 2018 3:13 pm

» The Arbalist Guild - Around the World
by stuckinthemud1 Sun May 20, 2018 5:32 am

» angles and rivets
by Geezer Fri May 18, 2018 1:16 pm

» morticed nut blocks
by Dark Factor Wed May 16, 2018 12:02 pm

» Crossbow triggers
by Croftage Mon May 14, 2018 1:41 pm

» Cocking lever
by c sitas Fri May 11, 2018 8:09 am

» Late roman crossbow
by Dark Factor Wed May 09, 2018 10:27 am

» Powermaster Madness
by Archer46176 Sun May 06, 2018 8:08 pm

» Fast loading crossbow
by septua Mon Apr 23, 2018 9:22 am

» lashing a glass prod in raw hide?
by kenh Sun Apr 22, 2018 7:00 am

» Balestra Veloce / Leonardo DaVinci
by msalazar2310 Fri Apr 20, 2018 10:37 am

» Goats Foot Lever
by Geezer Wed Apr 18, 2018 12:42 pm

» Hickory and Ipe 180lb flatbow
by actionbow Mon Apr 16, 2018 1:56 pm

» goat foot questions.
by Geezer Sat Apr 14, 2018 10:26 am


    Crossbow string question

    Share

    mazawakhan
    Fresh Blood

    Doesn't mean
    I'm new to crossbows


    Fresh Blood Doesn't meanI'm new to crossbows

    Posts : 14
    Join date : 2015-11-23

    Crossbow string question

    Post by mazawakhan on Wed Jan 27, 2016 10:54 am

    Im about to make a string for my new crossbow. I am going to make it out of hemp twine to keep it somewhat historically accurate. The twine has a 20 lb rating. What is the rule of thumb for making the string as far as strength goes? I think I remember it being 4x the pull weight of the bow. So that is this correct?
    avatar
    twedzel
    Fresh Blood

    Doesn't mean
    I'm new to crossbows


    Fresh Blood Doesn't meanI'm new to crossbows

    Posts : 47
    Join date : 2014-01-08
    Age : 45
    Location : Vancouver Island BC

    Re: Crossbow string question

    Post by twedzel on Wed Jan 27, 2016 1:26 pm

    Before you start, don't assume the packaging is correct. Do a few break tests to get the actual strength of some single strands. Hemp twine is usually made of shorter fibers (poorer quality) than what was historically used. This can leave it prone to weak points. So you want to make sure you are on the conservative side for number of strands per draw weight. Standard recurves tend to go 4-5x draw weight and crossbows higher as they are subject to more forces as well as abrasion. A lot of guys are using 28-36 strands of Dacron (which is rated to about 50lbs) on their Excalibur bows. So you can see a large margin of safety is probably a good idea given the forces involved and the potential damage to the bow if it breaks. Also heavy strings on crossbows is less of a detriment to performance than it is on recurves.
    avatar
    kenh
    Crossbow Junkie

    I live here!


    Crossbow JunkieI live here!

    Posts : 766
    Join date : 2012-08-03
    Age : 70
    Location : Living Aboard a Sailboat in Fort Myers, FL

    Re: Crossbow string question

    Post by kenh on Wed Jan 27, 2016 2:35 pm

    Hemp twine is not going to work very well.  Too short of fibers, and far too many of your 20# strands to make a safe thickness string for any reasonable poundage bow. 

    Long strand flax (not linen) cord would be much more historically accurate, not very expensive online, and much stronger.

    mazawakhan
    Fresh Blood

    Doesn't mean
    I'm new to crossbows


    Fresh Blood Doesn't meanI'm new to crossbows

    Posts : 14
    Join date : 2015-11-23

    Re: Crossbow string question

    Post by mazawakhan on Wed Jan 27, 2016 5:31 pm

    kenh wrote:Hemp twine is not going to work very well.  Too short of fibers, and far too many of your 20# strands to make a safe thickness string for any reasonable poundage bow. 

    Long strand flax (not linen) cord would be much more historically accurate, not very expensive online, and much stronger.
    Thanks for the input! Can you point me to a place that sells this stuff?
    avatar
    kenh
    Crossbow Junkie

    I live here!


    Crossbow JunkieI live here!

    Posts : 766
    Join date : 2012-08-03
    Age : 70
    Location : Living Aboard a Sailboat in Fort Myers, FL

    Re: Crossbow string question

    Post by kenh on Wed Jan 27, 2016 8:57 pm

    Craft Shops - sewing & needle work type crafts.  Some hobby shops.  Ebay -- search on flax cord or flax string.  Or just google "flax cord" and see how many thousands of places sell it...
    avatar
    OrienM
    Workshop Savvy

    Did you see my tool collection?


    Workshop SavvyDid you see my tool collection?

    Posts : 155
    Join date : 2014-08-01
    Age : 42
    Location : New Mexico, USA

    Re: Crossbow string question

    Post by OrienM on Thu Jan 28, 2016 7:07 am

    I made my string from hemp (cheap cord from walmart)...I'd agree it's weaker than some other natural fibers, but  it can be done if the string is made thick enough. Mine is fully 3/8" thick, with heavily reinforced loops...I quickly broke several lesser strings before I got this one to work.

    So, it can work, but using good quality flax will give you a better chance of success. Given the time it takes to make up a decent string (for me, about four hours...), it makes a lot of sense to use the best materials for the job.
    avatar
    Xamllew
    Tinkerer

    If there is a will, there is a way.


    TinkererIf there is a will, there  is a way.

    Posts : 72
    Join date : 2015-06-13
    Age : 26
    Location : Florida

    Re: Crossbow string question

    Post by Xamllew on Fri Jan 29, 2016 12:23 am

    Hemp gets pretty fuzzy but it certainly will work for bows under about 200lb draws. I've been using a fairly thick 3/8" flemish twist hemp string served with dacron for several months of regular use, the added thickness might rob a tiny bit of performance but I prefer the natural look of it over dacron.

    mazawakhan
    Fresh Blood

    Doesn't mean
    I'm new to crossbows


    Fresh Blood Doesn't meanI'm new to crossbows

    Posts : 14
    Join date : 2015-11-23

    Re: Crossbow string question

    Post by mazawakhan on Fri Jan 29, 2016 10:53 am

    Thanks for the replies! I had some B50 laying around and made an initial string yesterday on my homebrewed jig. I will try and make a hemp string this week sometime. My crossbow pulls just under 200.

    Sponsored content

    Re: Crossbow string question

    Post by Sponsored content


      Current date/time is Tue Jun 19, 2018 12:59 am