The Arbalist Guild

Would you like to react to this message? Create an account in a few clicks or log in to continue.

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

Latest topics

» [solved]Skane/Lillohus crossbow thread
by stuckinthemud1 Sat Aug 10, 2024 3:16 pm

» Colletiere a Charavines continuing experiment
by stuckinthemud1 Fri Aug 02, 2024 7:13 am

» What you building?
by hullutiedemies Tue Jul 09, 2024 12:39 am

» 12th Century Chinese Crossbow Chronographed
by stuckinthemud1 Fri Nov 24, 2023 3:50 pm

» Crossbow Stock
by kenh Tue Oct 31, 2023 6:19 am

» Cocking - how
by stuckinthemud1 Thu Aug 03, 2023 4:24 am

» Questions around heavy crossbow lath buildin
by stuckinthemud1 Wed Apr 26, 2023 1:10 am

» Arab Crossbow
by stuckinthemud1 Tue Apr 25, 2023 7:57 am

» prod angle, and lever trigger for sale anyone?
by stuckinthemud1 Mon Mar 20, 2023 5:54 am

» flexible string
by jasper1978 Mon Mar 20, 2023 1:25 am

» jens sensfelder
by jasper1978 Wed Mar 08, 2023 11:58 pm

» 400lb Windlass crossbow bolts weight and accuracy shooting high.
by stuckinthemud1 Sun Mar 05, 2023 2:53 pm

» Codex Löffelholz crossbow
by stuckinthemud1 Tue Jan 24, 2023 4:14 pm

» Digitar prodsc
by stuckinthemud1 Sun Jan 15, 2023 2:42 pm

» Troubleshooting
by Andy. Fri Jan 06, 2023 12:29 pm

» Wood Prods
by stuckinthemud1 Fri Dec 30, 2022 12:47 pm

» Colletiere a Charavines crossbow
by stuckinthemud1 Fri Dec 30, 2022 8:54 am

» Simplified Löffelhotz speedloader
by stuckinthemud1 Fri Dec 09, 2022 4:05 pm

» Fiberglass H-bows
by c sitas Sat Nov 12, 2022 8:44 am

» Bad Antler
by drawknife Sat Nov 12, 2022 3:48 am

» Anyone make their own bolts?
by Juniper Mon Oct 17, 2022 8:20 am

» Josef alm in English
by Juniper Sat Oct 15, 2022 4:22 am

» Qin/Han lock drawings
by kenh Fri Sep 23, 2022 8:16 pm

» stirrup dimensions?
by stuckinthemud1 Thu Sep 01, 2022 1:49 pm

» Skane/Lillohus lockbow information needed
by stuckinthemud1 Sun Aug 14, 2022 6:23 am


5 posters

    Trouble with my Gafa

    msalazar2310
    avatar
    msalazar2310
    Fresh Blood

    Doesn't mean
    I'm new to crossbows


    Fresh Blood Doesn't meanI'm new to crossbows


    Posts : 14
    Join date : 2015-04-19
    Age : 79
    Location : Mexico
    • Post n°1

    Trouble with my Gafa Empty Trouble with my Gafa

    Post by msalazar2310 Mon May 21, 2018 1:21 pm

    Trouble with my Gafa Img_0211
    Trouble with my Gafa Img_0210
    By trying to span the bow, applying force with a long lever, two things happen:

    1.- The string goes far above the nut making impossible to cock it. Geezer suggested me to go  further back passing the nut and than slowly go back and the string goes down by itself. This I did it and finally the string was in place

    2.-The force I need to pull the string back is too much, (nothing to do with Tods videos where he pulls the Gafa lever with two fingers).

    My bow is 900mm. long, 40mm. wide in the middle, and 11mm. wide at the tips, the bow is made of automotive spring steel, with a thickness of 6.4 mm.6.4mm. 

    I would appreciate if you make me your recommendations for I am sure that I have done somethin wrong, possibly in the geometry of my gafa, or the bow with these meassures has got a draw weight far above to be cocked with it and I need a cranekin.

    Manuel Salazar
    • Back to top
    Dark Factor
    Dark Factor
    Dark Factor
    Tinkerer

    If there is a will, there is a way.


    TinkererIf there is a will, there is a way.


    Posts : 68
    Join date : 2017-10-16
    Age : 40
    Location : Belgium
    • Post n°2

    Trouble with my Gafa Empty Re: Trouble with my Gafa

    Post by Dark Factor Tue May 22, 2018 12:05 pm

    What's the bow draw weight? I've never used this kind of lever but only the wooden one (from the stirrup) and with it we have about 2-3 times more force, not more.
    Force with 2 fingers doesn't mean a lot. I shoot 60lbs bows with 2-3 fingers. Stronger seems impossible for me but a friend of me can draw 130lbs bows with 2 fingers too and it doesn't seem hard for him !
    • Back to top
    msalazar2310
    avatar
    msalazar2310
    Fresh Blood

    Doesn't mean
    I'm new to crossbows


    Fresh Blood Doesn't meanI'm new to crossbows


    Posts : 14
    Join date : 2015-04-19
    Age : 79
    Location : Mexico
    • Post n°3

    Trouble with my Gafa Empty Re: Trouble with my Gafa

    Post by msalazar2310 Tue May 22, 2018 6:27 pm

    I do not know thw draw wight, I assume it may be 200 pound
    • Back to top
    msalazar2310
    avatar
    msalazar2310
    Fresh Blood

    Doesn't mean
    I'm new to crossbows


    Fresh Blood Doesn't meanI'm new to crossbows


    Posts : 14
    Join date : 2015-04-19
    Age : 79
    Location : Mexico
    • Post n°4

    Trouble with my Gafa Empty Re: Trouble with my Gafa

    Post by msalazar2310 Wed May 23, 2018 2:07 pm

    https://youtu.be/iIkxyjVu9gc

    This is what I mean by "holding the lever with two fingers"
    • Back to top
    c sitas
    avatar
    c sitas
    Crossbow Junkie

    I live here!


    Crossbow JunkieI live here!


    Posts : 547
    Join date : 2012-11-24
    • Post n°5

    Trouble with my Gafa Empty Re: Trouble with my Gafa

    Post by c sitas Wed May 23, 2018 4:07 pm

    yes ,that is all well and good. Notice where the fingers of the lever set when starting out. He has lots  of leverage this way. The way your's are setting ,you have no leverage at all. Fingers are too long.
    • Back to top
    msalazar2310
    avatar
    msalazar2310
    Fresh Blood

    Doesn't mean
    I'm new to crossbows


    Fresh Blood Doesn't meanI'm new to crossbows


    Posts : 14
    Join date : 2015-04-19
    Age : 79
    Location : Mexico
    • Post n°6

    Trouble with my Gafa Empty Gafa

    Post by msalazar2310 Thu May 24, 2018 8:47 am

    Thanks a lot, I made the fingers longer as necessary in order to have "room" for corrections, one ting I also can do is to relocate the pin, however I will have to guess in what direction, this prior to modify the curve of the fingers, whtever ideas you got, let me know
    Manuel
    • Back to top
    Dark Factor
    Dark Factor
    Dark Factor
    Tinkerer

    If there is a will, there is a way.


    TinkererIf there is a will, there is a way.


    Posts : 68
    Join date : 2017-10-16
    Age : 40
    Location : Belgium
    • Post n°7

    Trouble with my Gafa Empty Re: Trouble with my Gafa

    Post by Dark Factor Thu May 24, 2018 10:18 am

    Not sure the length of the 2 fingers of the lever are a problem. If it's longer than necessary, there is no problem.
    But is it the final lever or an old picture ? I mean there is no lever limb. For me, the length of the limb is the force multiplier... the longer the better for multiplying the force.
    That's only physics... if the final distance between the nut and the lever axis is 4 times smaller than the distance between your hand and this axis, you multiply force by 4... if more, this will be easier
    • Back to top
    Geezer
    Geezer
    Geezer
    Master Crossbowyer
    Master Crossbowyer


    Posts : 1194
    Join date : 2010-01-12
    Age : 76
    Location : Austin, Texas, USA
    • Post n°8

    Trouble with my Gafa Empty Re: Trouble with my Gafa

    Post by Geezer Thu May 24, 2018 12:31 pm

    Certainly the lever in the photo has no upper limb.  That's what gives you the 'leverage'.  Also note that the 'fingers' on the illustrated lever are mounted on a thru-axle (Yes, Payne Gallwey's pattern does it that way) but in fact plenty of 'gafa' or 'goatsfoot' levers hang the fingers on two rivers, with no axle.  The advantage to doing it that way is that the axle doesn't limit the range of motion on your lever.  I have seen a few period bows with marks on the stock where the axle for fingers would end up stricking the top, but I've also seen lots of these bows (Padre Island bow or Maltese bows) with no such marks. 
    In some cases, the missing upper limb is immovable, but most of them swivel, so the lever can be folded when not in use.  Geezer.
    • Back to top
    drawknife
    avatar
    drawknife
    Fresh Blood

    Doesn't mean
    I'm new to crossbows


    Fresh Blood Doesn't meanI'm new to crossbows


    Posts : 37
    Join date : 2011-02-11
    Age : 75
    Location : Barnsley, England
    • Post n°9

    Trouble with my Gafa Empty Gafa/Goatfoot lever

    Post by drawknife Fri Jun 15, 2018 2:56 am

    Hi,
    Just to add what has been said;
    The shape of the bent levers near the claws is not the correct shape, See Payne Galways goatsfoot lever design. (should be on the internet).
    Your device needs an extended lever forward of the  bars that you use to pull the device back. this will give you more leverage.
    The smoother you can polish the sliding surfaces the easier it will be to pull.
    I made one of these to (almost) Payne-Galways design and it worked but still lifted the string. It is all in the shape of the curved legs.
    Hope this helps
    • Back to top
    Sponsored content

    Sponsored content


    • Post n°10

    Trouble with my Gafa Empty Re: Trouble with my Gafa

    Post by Sponsored content

    • Back to top

      Current date/time is Wed Nov 27, 2024 5:30 pm