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

Latest topics

» Crossbow with built in lever?
by kenh Today at 5:50 am

» Chinese crossbow with auxiliary string?
by stm2010 Mon Jun 26, 2017 9:48 am

» 15th century saxon prods
by Geezer Mon Jun 26, 2017 7:34 am

» Yet another one
by jocky Sun Jun 25, 2017 7:09 am

» Crusader crossbow
by c sitas Thu Jun 22, 2017 9:41 pm

» Whamo showed up, prod replacement ideas
by kenh Mon Jun 19, 2017 4:25 pm

» Renaissance Sporting crossbow
by tony a Mon Jun 19, 2017 2:10 am

» loose laminate issues
by c sitas Sun Jun 18, 2017 8:42 am

» Of Bows and Torsion Engines
by c sitas Fri Jun 16, 2017 2:55 pm

» My second crossbow
by Daniel Levesque Fri Jun 16, 2017 10:48 am

» Need to locate Windlass Crossbow, pre 1600, in Rome, Venice, or Florence
by 8fingers Tue Jun 13, 2017 11:24 pm

» Crossbow Projectiles
by Geezer Tue Jun 13, 2017 8:10 pm

» Greetings!
by OnlyHuman Mon Jun 12, 2017 7:40 am

» Anyone know what this is?
by Yuki23emma Sun Jun 11, 2017 2:54 pm

» Prod specs
by Onager Lovac Mon Jun 05, 2017 4:25 pm

» Finished Crossbow
by kenh Sat Jun 03, 2017 8:34 pm

» The Arbalist Guild - Around the World
by Turnigy Fri Jun 02, 2017 1:25 pm

» Reverse draw "compound" build
by Turnigy Fri Jun 02, 2017 1:20 pm

» Casting Resource
by White Oak Wed May 31, 2017 2:28 am

» The Road so far......
by White Oak Mon May 29, 2017 7:17 am

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

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


    Practical differences in bolt tracks?

    Share
    avatar
    Basilisk120
    Moderator
    Moderator

    Posts : 548
    Join date : 2010-03-01
    Age : 38
    Location : Arizona

    Practical differences in bolt tracks?

    Post by Basilisk120 on Thu Aug 05, 2010 5:44 pm

    I was wondering if there was any noticable difference between a grooved bolt track and a dove tail mount thats at the end in a "trad" crossbow? Assuming both are properly made and using good materials.

    Is the dove tail mount faster but only noticable if you have a chronograph.

    I may be overthinking the issue too.



    Something Something Dark Side
    avatar
    Tinker
    Techno Weeny Supreme
    Techno Weeny Supreme

    Posts : 75
    Join date : 2010-07-19
    Location : Idaho, USA

    Re: Practical differences in bolt tracks?

    Post by Tinker on Fri Aug 06, 2010 4:59 pm

    That was a question I had waiting in the wings. Be curious also to what the people 'in the know' say scratch

    Tinker
    avatar
    Geezer
    Master Crossbowyer
    Master Crossbowyer

    Posts : 933
    Join date : 2010-01-12
    Age : 69
    Location : Austin, Texas, USA

    Bolt tracks

    Post by Geezer on Sun Aug 08, 2010 9:04 am

    Geezer here, ready to spout off about bolt-tracks. In my experience, full-grooved tracks are the most secure... they'll simply hold your bolt in place better if you're hunting or playing combat games, but a full groove must be absolutely straight and very-very slick for best results. Lining the groove with polished brass, bone, or a slick synthetic, like Micarta or Delrin will noticeably improve your bolt-velocity (one customer reported a 10% (20 fps) increase in speed, just by lining the groove with Delrin)
    A simple bone bolt-rest (sometimes dovetailed into the stock, sometimes a permanent part of a bone top) should increase velocity, thanks to lower friction, (and you can circumvent necessity for a really straight groove). A rest will probably loft your bolt just a bit on takeoff, giving you a longer point-blank range, but if the rest is TOO high, you'll get erratic flight: porpoising or whirligging. Also, misfires or dry-firing can knock your bone rest right out of its dovetail, even if the rest is mounted as far forward as possible.
    For this reason, I often build rest-type bows with a simple ramp and partial groove. Ramps are fairly common on central european bows from 14th-15th centuries. I suspect they were partically intended to slow the string at the end of its run to reduce stopping-shock, which might cause the glue-bonds in composite prods to separate over time
    You can make your ramp out of any hard, slick material. Usually it starts at the string-rest position and will be about 1/4 inch high at the fore end of the table. Again, if you find your bolts tend to porpoise right after launching, your rest is too high.
    As for which is better: I regard this as another matter of choice based on needs. Grooves are more secure, rests, particularly those in dovetails, admit a certain amount of adjustment, but may also require some fiddling to get right, and they are subject to sudden disappearance downrange in the event of dryfire or misfire.
    Does that help? Geezer

    Sponsored content

    Re: Practical differences in bolt tracks?

    Post by Sponsored content


      Current date/time is Thu Jun 29, 2017 6:26 am