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

Latest topics

» Crossbow bullet bolt's
by Geezer Yesterday at 5:27 pm

» How close to original would you go
by Geezer Sat Mar 17, 2018 10:30 am

» Skane Lockbow replica (and making of)
by Dark Factor Tue Mar 13, 2018 11:46 am

» Moving the nut lugs forward.
by Dark Factor Mon Mar 12, 2018 12:33 pm

» Bridle length and waxing?
by Geezer Sun Mar 11, 2018 9:08 pm

» Draw length VS. prod length on wood prods
by Dark Factor Tue Feb 27, 2018 10:32 am

» Typical dimensions of late Gothic composite bows
by Dark Factor Sun Feb 25, 2018 4:10 am

» Medieval stirrup crossbow
by Dark Factor Fri Feb 23, 2018 10:55 am

» Reciprocating Saw?
by stuckinthemud1 Sun Feb 18, 2018 8:59 am

» Help Needed with Bullet Crossbow Prod
by Crossbowmen Sat Feb 17, 2018 2:43 pm

» Leaving the prod strung?
by JacobL Sat Feb 17, 2018 2:37 pm

» Crossbow for a 8 year old kid
by Daniel Levesque Fri Feb 16, 2018 2:11 pm

» Chinese carpenter make bed crossbow, earlest repeating crossbow and chu-ko-nu
by c sitas Thu Feb 15, 2018 8:49 pm

» Linen or Hemp String
by kenh Thu Feb 15, 2018 10:47 am

» New member
by Geezer Sun Feb 11, 2018 7:00 pm

» Why the ratchet in Greek gastraphetes can hold on the string force?
by Dark Factor Wed Feb 07, 2018 12:20 pm

» How to calculate potential energy in a compound system?
by Alan Case Mon Feb 05, 2018 8:02 pm

» Nut from a pool que ball?
by chaz Mon Feb 05, 2018 7:46 am

» Great Machines
by rickraedeke Thu Feb 01, 2018 8:32 am

» Crossbow Legality Help (Canada)
by JacobL Tue Jan 30, 2018 7:31 pm

» Adding a steel sear insert?
by fester Fri Jan 19, 2018 12:53 pm

» MISFIRES! ...String passing underneath bolt!
by Anatine Duo Fri Jan 12, 2018 6:18 pm

» Best diameter delrin for nut ?
by Geezer Thu Jan 11, 2018 12:08 pm

» Opinions on this Thing?
by JacobL Wed Jan 10, 2018 12:45 pm

» Ideas and designs for a Crossbow Inside A Pipe?
by JacobL Tue Jan 09, 2018 6:38 pm

    affects of brace height


    Fresh Blood

    Doesn't mean
    I'm new to crossbows

    Fresh Blood Doesn't meanI'm new to crossbows

    Posts : 46
    Join date : 2012-10-21
    Location : abbeville, la

    affects of brace height

    Post by panne on Wed Dec 12, 2012 9:46 am

    looking for some insight on how different brace heights affect performance on a crossbow, without changing the prod mounting and trigger locations, using the same weight bolt.

    Todd the archer
    Crossbow Junkie

    I live here!

    Crossbow JunkieI live here!

    Posts : 581
    Join date : 2010-02-25
    Age : 55
    Location : sellersville,pa.

    Re: affects of brace height

    Post by Todd the archer on Wed Dec 12, 2012 2:26 pm

    Lower brace height gives a longer power stroke and thus faster speed. However most crossbows we build using a one piece prod have the prod canted. Braced too low and you increase string drag and the string might jump off the nocks, too high and the string might travel across the deck too high and could cause a miss fire.


    Fresh Blood

    Doesn't mean
    I'm new to crossbows

    Fresh Blood Doesn't meanI'm new to crossbows

    Posts : 46
    Join date : 2012-10-21
    Location : abbeville, la

    Re: affects of brace height

    Post by panne on Thu Dec 13, 2012 7:24 am

    so if the string pressure and brace height is correct the string should have enough pressure in the unspanned position to keep the string in contact with the rail through the whole draw length, since the string pressure will be decreased in the spanned position, directly proportional to the degree of prod angle? so if it misfires, lowering the brace height in small increments to increase the string pressure should help correct misfires, but will also slow the FPS due to the increase in drag as it moves forward?
    Master Weaponsmith
    Master Weaponsmith

    Posts : 560
    Join date : 2010-12-23
    Location : Near Philly USA

    Re: affects of brace height

    Post by mac on Thu Dec 13, 2012 9:52 am


    There are many different ways that a bolt can "misfire". So long as the center of the string travels in a way that will keep it pressed against the center of the end of the bolt, it does not much matter what the brace height is.

    The danger which Todd mentioned is that a low brace height can sometimes cause the string loops to get over the upper shoulders of the nocks. This will cause the string to leave the bow, and the prod limbs to continue traveling forward unchecked. The resulting stress reversal is decidedly prejudicial to the life of the prod. Indeed, an organic prod might fail right then and there. Therefore, this particular mode of "misfire" should be guarded against.

    In general, I think you will find that if you lower the brace height a bit, the increase in friction of the string on the top of the tiller is more than compensated for by the longer stroke. That is, so long as the string still has tension in its resting position.


    Sponsored content

    Re: affects of brace height

    Post by Sponsored content

      Current date/time is Mon Mar 19, 2018 2:32 am