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

Latest topics

» GLOSSARY OF TERMS
by Onager Lovac Wed May 24, 2017 6:41 pm

» Reverse draw "compound" build
by FrenckBrambo Tue May 23, 2017 6:18 am

» Prod specs
by White Oak Tue May 23, 2017 4:23 am

» Crusader crossbow
by c sitas Mon May 22, 2017 8:48 am

» The Arbalist Guild - Around the World
by White Oak Mon May 22, 2017 4:03 am

» Hello from Maine
by White Oak Sun May 21, 2017 11:06 pm

» Need to locate Windlass Crossbow, pre 1600, in Rome, Venice, or Florence
by Vincenti Thu May 18, 2017 7:18 pm

» Leonardo Da Vinci string with suport-rolls
by Oppenheimer Tue May 16, 2017 11:40 am

» Compact repeating compound project
by Phil Abrahams Mon May 08, 2017 2:10 pm

» Trying to reduce the power stroke in my next project
by octavioaugusto.oliveira Thu Apr 27, 2017 1:27 pm

» The Road so far......
by Onager Lovac Tue Apr 25, 2017 4:07 pm

» Its good to be back!!
by Juan galeano Tue Apr 25, 2017 9:31 am

» The crossbow...What is?!
by octavioaugusto.oliveira Sat Apr 22, 2017 2:07 pm

» I need your advices on a new crossbow project
by Daniel Levesque Fri Apr 21, 2017 12:58 pm

» Guidance Designing My First Slinger
by kenh Thu Apr 13, 2017 8:17 pm

» New member
by harry6855 Thu Apr 13, 2017 8:28 am

» Chinese style crossbow trigger 3d modeled with templates.
by Bs1110101 Thu Apr 13, 2017 6:14 am

» Berkhamsted Castle and Glasgow Museum wooden prod crossbow
by hullutiedemies Wed Apr 12, 2017 8:52 am

» Hello from Asia
by Daniel Levesque Wed Apr 12, 2017 6:49 am

» Medieval crossbow modeled in Tinkercad, with variant trigger design.
by Bs1110101 Mon Apr 10, 2017 1:42 pm

» New project"s"
by kenh Sun Apr 09, 2017 2:38 pm

» New member here!
by c sitas Thu Apr 06, 2017 7:49 am

» Fixing a bad delflex
by Daniel Levesque Tue Apr 04, 2017 11:13 am

» H L Bailey Plans
by ora8i Sun Apr 02, 2017 1:49 am

» Top of Crossbow (launch?)
by Geezer Thu Mar 30, 2017 9:41 pm


    Finnish crossbow project

    Share
    avatar
    Juri
    Fresh Blood

    Doesn't mean
    I'm new to crossbows


    Fresh Blood Doesn't meanI'm new to crossbows

    Posts : 7
    Join date : 2012-01-15
    Location : Finland

    Finnish crossbow project

    Post by Juri on Thu Feb 05, 2015 7:30 am

    Hello guys!
    I am Juri, from Finland. I have been lurking here for a while but now is the time to start a project of my own.
    Me and my colleague, Jari, managed to get two pretapered spring steel billets from master smith Taisto Kuortti. We decided to try two traditional Finnish crossbows. We have never made steel prods or crossbows before. So, we probably will need your generous help in various stages...
    Here is some dravings about the model, made by etnologist U.T. Sirelius 1919.
    avatar
    Juri
    Fresh Blood

    Doesn't mean
    I'm new to crossbows


    Fresh Blood Doesn't meanI'm new to crossbows

    Posts : 7
    Join date : 2012-01-15
    Location : Finland

    Re: Finnish crossbow project

    Post by Juri on Thu Feb 05, 2015 7:50 am

    Here is where we started. 860 x 50 mm, about 34 x 2 inches. Imatra MS 416 spring steel.
    Tapering from 8mm, 0,3" from center to 4mm, 0,15" at the tips.




    Cut in shape. 45 mm, 1,77" at the center, 27 mm, 1,06" at the tips.



    Then "a bit" grinding to make the both limbs as symmetrical as possible.



    to be continued...
    avatar
    Juri
    Fresh Blood

    Doesn't mean
    I'm new to crossbows


    Fresh Blood Doesn't meanI'm new to crossbows

    Posts : 7
    Join date : 2012-01-15
    Location : Finland

    Re: Finnish crossbow project

    Post by Juri on Thu Feb 05, 2015 7:54 am

    Shaping the tips. That's Jari.



    avatar
    Juri
    Fresh Blood

    Doesn't mean
    I'm new to crossbows


    Fresh Blood Doesn't meanI'm new to crossbows

    Posts : 7
    Join date : 2012-01-15
    Location : Finland

    Re: Finnish crossbow project

    Post by Juri on Thu Feb 05, 2015 8:00 am

    Nocks welded from 12 mm, 0,5" bolts.







    And the final shape.

    avatar
    Juri
    Fresh Blood

    Doesn't mean
    I'm new to crossbows


    Fresh Blood Doesn't meanI'm new to crossbows

    Posts : 7
    Join date : 2012-01-15
    Location : Finland

    Re: Finnish crossbow project

    Post by Juri on Thu Feb 05, 2015 8:37 am

    Ok, shaping the side profile.
    We also used a template made of thin metal plate to get the shape right and symmetric.



    Me inspecting quality.



    After steel brushing.

    avatar
    mac
    Master Weaponsmith
    Master Weaponsmith

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

    Re: Finnish crossbow project

    Post by mac on Thu Feb 05, 2015 9:32 am

    Juri,

    The bow's widths and thicknesses look good to me, but I am worried about the amount of recurve at the tips.  Check it against the bow in the first pic you posted and I think you will agree.  As it is, the string will rest on the bellies of the limbs when it brace height.  In my experience that will make the string tend to come off at the end of the shot.  That's bad for the bow as well as your peace of mind Shocked

    This should be easy to change if you have not hardened it yet.

    Mac
    avatar
    Geezer
    Master Crossbowyer
    Master Crossbowyer

    Posts : 909
    Join date : 2010-01-12
    Age : 69
    Location : Austin, Texas, USA

    Re: Finnish crossbow project

    Post by Geezer on Thu Feb 05, 2015 10:39 am

    Thanks guys for posting the stuff about Finnish crossbows. It allowed me to chase down Sirelius' 1919 drawings online.  I've had lousy photocopies of those bows for years... faint and small sized.  Now I've got fresh new ones that can be blown up to any size I want.  Geezer
    avatar
    Juri
    Fresh Blood

    Doesn't mean
    I'm new to crossbows


    Fresh Blood Doesn't meanI'm new to crossbows

    Posts : 7
    Join date : 2012-01-15
    Location : Finland

    Re: Finnish crossbow project

    Post by Juri on Thu Feb 05, 2015 11:25 am

    Thank's for the replys!
    Mac, unfortunately It is allready hardened. I have also started to doubt there might be too much reflex.
    If the string jumps off, then the prod must be shaped and hardened again. We will see...

    Well, here is the hardening process.
    That was made by a professional smith Jarkko Kotakorpi, company called Vallilan Takomo. They are making leaf springs for vehicles there.



    For a case that the prods twist in hardening I welded them together. The smith also added a clamp in the middle.



    Here it goes! First to owen 940° C, 1724° F and then to water.
    This stage can be a step forward or a looong jump backwards, if something goes wrong.



    I tried to film everything, but I was so nervous that I pushed a wrong button in my camera.
    However, it went well! Here is my relieved face with the prods, hard as a glass.



    After this the prods went for annealing 430° C, 806° F for 2 hours. That owen is just behind my back.
    avatar
    Juri
    Fresh Blood

    Doesn't mean
    I'm new to crossbows


    Fresh Blood Doesn't meanI'm new to crossbows

    Posts : 7
    Join date : 2012-01-15
    Location : Finland

    Re: Finnish crossbow project

    Post by Juri on Thu Feb 05, 2015 11:37 am

    Well, this is the situation today.
    Not a glue about the brace height, draw lenght or draw weight yet.
    First experiment with a long string, I'm trying to figure out how long and how thick should the real string be. I'm planning to use B-50 Dacrong at first.
    The tips have moved 5 cm, 2" and the weight is allready 190 pounds. Looks like I need a bigger scale!

    avatar
    ali.j
    Tinkerer

    If there is a will, there is a way.


    TinkererIf there is a will, there  is a way.

    Posts : 75
    Join date : 2013-10-30
    Age : 23
    Location : iran- shiraz

    Re: Finnish crossbow project

    Post by ali.j on Thu Feb 05, 2015 3:29 pm

    nice. Shocked

    Hermit
    Workshop Savvy

    Did you see my tool collection?


    Workshop SavvyDid you see my tool collection?

    Posts : 245
    Join date : 2013-09-10

    Re: Finnish crossbow project

    Post by Hermit on Thu Feb 05, 2015 5:29 pm

    Juri,look at my posting today 'R.D.T' experiments.The posting has a method I have used to determine the number of stands needed for any given draw weight,this will give you an idea of string thickness.It worked for me,hope it works for you.
                                                           Hermit.

    Sponsored content

    Re: Finnish crossbow project

    Post by Sponsored content


      Current date/time is Sun May 28, 2017 12:35 am