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

» 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

» Colletiere a Charavines continuing experiment
by stuckinthemud1 Sat Oct 07, 2023 5:36 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

» [solved]Skane/Lillohus crossbow thread
by stuckinthemud1 Sun Mar 19, 2023 7:44 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

» need help contacting le musee Dauphinois Grenoble
by stuckinthemud1 Sat Aug 13, 2022 3:22 pm


5 posters

    Nut dimensions

    avatar
    benjaminh123
    Techno Weeny

    Lets put a laser on it!!!


    Techno WeenyLets put a laser on it!!!


    Posts : 54
    Join date : 2015-02-23

    Nut dimensions Empty Nut dimensions

    Post by benjaminh123 Sat Mar 28, 2015 5:43 pm

    For a 1.25" round nut, how far up do you usually put the notch for the string from center?
    avatar
    phuphuphnik
    Workshop Savvy

    Did you see my tool collection?


    Workshop SavvyDid you see my tool collection?


    Posts : 151
    Join date : 2013-12-02
    Location : The wastes West of Chicago

    Nut dimensions Empty Re: Nut dimensions

    Post by phuphuphnik Sun Mar 29, 2015 7:04 am

    My rule of thumb is to have it 1.25-1.5 times the string diameter. My strings for the 150# are about 1/4" so the hook is an east 3/8"  I'm using dacron (D-50) Old horn nut hooks seem huge, but the strings were really thick as well.
    Geezer
    Geezer
    Master Crossbowyer
    Master Crossbowyer


    Posts : 1194
    Join date : 2010-01-12
    Age : 76
    Location : Austin, Texas, USA

    Nut dimensions Empty Re: Nut dimensions

    Post by Geezer Sun Mar 29, 2015 8:03 am

    My rule is to sink the roller nut 2/3 into the stock.  So 1/3 projects, and that's how high my lugs are.  If you sink the nut as much as 3/4 you won't be able to take it out of the top of its socket... will have to come out sideways.  Geezer.
    mac
    mac
    Master Weaponsmith
    Master Weaponsmith


    Posts : 561
    Join date : 2010-12-23
    Location : Near Philly USA

    Nut dimensions Empty Re: Nut dimensions

    Post by mac Sun Mar 29, 2015 11:45 am

    I think I am seeing something like a ratio of 7 to 3 in these X ray pics by Harmuth.  So, a 1 1/4" nut would end up with 7/8" buried, 3/8" exposed, and it's axis 1/4" below the surface of the tiller.

    This has been my "go to" image when planning a crossbow, and I have had good results by making my sections through the nut well look more or less like this.

    By Geezer's reckoning it's 7/10, which is bit deeper than his recommendation of 2/3, and just shy of his "don't go there" depth of 3/4. 

    Nut dimensions Nut_xr10

    Mac
    Geezer
    Geezer
    Master Crossbowyer
    Master Crossbowyer


    Posts : 1194
    Join date : 2010-01-12
    Age : 76
    Location : Austin, Texas, USA

    Nut dimensions Empty Re: Nut dimensions

    Post by Geezer Sun Mar 29, 2015 5:51 pm

    If it works, it works, and certainly in most respects a deeper socket is better, so long as you have enough lug to hold the string and can get the nut in and out when you need to.  Geezer
    mac
    mac
    Master Weaponsmith
    Master Weaponsmith


    Posts : 561
    Join date : 2010-12-23
    Location : Near Philly USA

    Nut dimensions Empty Re: Nut dimensions

    Post by mac Sun Mar 29, 2015 6:11 pm

    That is the sine qua non

    You have me wondering, though, exactly where that nut-removal limit is.  I will do up some two-dimensional models some day and see if I can determine it to an exactitude.  I have a sneaking suspicion that it may depend on the shape of the nut fingers, but I have not gotten beyond that yet.

    Mac
    Geezer
    Geezer
    Master Crossbowyer
    Master Crossbowyer


    Posts : 1194
    Join date : 2010-01-12
    Age : 76
    Location : Austin, Texas, USA

    Nut dimensions Empty Re: Nut dimensions

    Post by Geezer Sun Mar 29, 2015 7:06 pm

    Got it in one, Mac. It's possible to finess the nut removal by changing shape of the lugs, deepening the platform behind it, and also whether you want a lip of the platform to actually show above the back of the socket (I prefer to do that, rather than having it fit flush for various reasons) If all else fails, you can always back-bevel the edges of the socket a bit to squeeze things in.  Geezer.
    mac
    mac
    Master Weaponsmith
    Master Weaponsmith


    Posts : 561
    Join date : 2010-12-23
    Location : Near Philly USA

    Nut dimensions Empty Re: Nut dimensions

    Post by mac Sun Mar 29, 2015 8:45 pm

    Curiosity got the better of me, and I made up a series of drawings to investigate the nut-depth thing. I drew this out with a 1 1/4" (32mm) nut, and set it into the "tiller" at different depths based on 1/16" increments.  Since 1 1/4" is 20/16,  I described each depth in terms of fractions of 20, and then as a percents. The string notch is the most typical shape for historical nuts from the high middle ages on.


    The first column shows the nut in the locked position, with a 5/16" (8mm) diameter string against the fingers. 

    The second column shows the nut rotating through the middle of the release phase.

    The third column shows the nut passing through (or falling to pass through) the tightest place in the nut well during the removal process. 

    At 65%, the lock is good and the nut will come out very easily.  The only down side is how the string is carried up above the "deck" a little bit.  Making the notch a bit deeper would fix that if it turned out to be a problem.

    At 70% the string lifting thing has worked its self out.

    At 75% the nut is still readily removable.

    At 80% the engagement of the string with the fingers starts to look a bit dicey, and the nut may or may not come out.  At this level of modeling, I can not be sure.

    At 85% the fingers are treacherously short and the nut is definitely stuck in the nut well for good.


    Nut dimensions Sdc12910
    All things considered, I feel good about the range from 65 to 75 percent.  I think that for medieval nuts, one would do well to shoot for 70% and accept an error of up to 5% either way.

    Mac
    Anatine Duo
    Anatine Duo
    Tinkerer

    If there is a will, there is a way.


    TinkererIf there is a will, there  is a way.


    Posts : 65
    Join date : 2013-10-07
    Location : Muskoka, Canada

    Nut dimensions Empty Re: Nut dimensions

    Post by Anatine Duo Mon Mar 30, 2015 11:31 am

    That illustrates it very well, Thanks Mac
    avatar
    benjaminh123
    Techno Weeny

    Lets put a laser on it!!!


    Techno WeenyLets put a laser on it!!!


    Posts : 54
    Join date : 2015-02-23

    Nut dimensions Empty Re: Nut dimensions

    Post by benjaminh123 Mon Mar 30, 2015 11:45 am

    Thanks everyone; this forum is great

    Sponsored content


    Nut dimensions Empty Re: Nut dimensions

    Post by Sponsored content


      Current date/time is Thu Mar 28, 2024 1:01 pm