modified OTT fork (rubber rests)

Discussion in 'General Slingshot Discussions' started by Arturo Borquez, Jan 25, 2013.

  1. Arturo Borquez

    Arturo Borquez Administrator

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    it is too hot here to continue rasping the huge piece of steel I choose for the PFS and took a break ... and this came into my mind ... I thought mainly in a way to prevent bands abrasion, and after some test shoots I am believing that it also improves accuracy ... have any of you tested something like this ??<br>Cheers<br>Arturo<br>[​IMG]
     
  2. Lars

    Lars The Evil Genious

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    <div>i think it is no bonus for accurarcy<br>but for bandlife maybe</div><div class="clear"></div><div class="signature_div">
    <br>hmm nice slingshot!<br>maybe needs some sanding and oiling <img src="http://illiweb.com/fa/i/smiles/icon_lol.gif" alt="Laughing" longdesc="7"><br><a href="http://www.youtube.com/user/selfmademilitary" class="postlink" target="_blank" rel="nofollow">my Channel . . . . . Selfmademilitary</a><br><a href="http://slingshotforum.forumieren.com/" class="postlink" target="_blank" rel="nofollow">My Forum</a>
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  3. Saderath

    Saderath Senior Member

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    Nice idea! Never tried something like this, i am currently experimenting with tabs for improving accuracy with instinctive shooting.
     
  4. Arturo Borquez

    Arturo Borquez Administrator

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    <table width="90%" cellspacing="1" cellpadding="0" border="0" align="center">
    <tr><td><span class="genmed"><b>Lars wrote:</b></span></td></tr>
    <tr><td class="quote">i think it is no bonus for accurarcy<br>but for bandlife maybe</td></tr>
    </table>
    <span class="postbody"><br>maybe you are right ... maybe I am in a "good day" ... time will answer this ...</span>
     
  5. Arturo Borquez

    Arturo Borquez Administrator

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    <table width="90%" cellspacing="1" cellpadding="0" border="0" align="center">
    <tr><td><span class="genmed"><b>Saderath wrote:</b></span></td></tr>
    <tr><td class="quote">Nice idea! Never tried something like this, i am currently experimenting with tabs for improving accuracy with instinctive shooting.</td></tr>
    </table>
    <span class="postbody"><br>it would be nice to have feedback ... I noticed that my bands rubbed the fork tip unevenly (little scratch sounds when pulling and releasing slow without shooting) ... now this sound disappeared and I can see the 2 or 3 cm elongated near the fork that slips very gently ...</span>
     
  6. onnod

    onnod Im from Holland, isnt that weird?

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    Hmm this could do something to the friction i also experience <img src="http://illiweb.com/fa/i/smiles/icon_scratch.png" alt="scratch" longdesc="33">
     
  7. Arturo Borquez

    Arturo Borquez Administrator

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    <table width="90%" cellspacing="1" cellpadding="0" border="0" align="center">
    <tr><td><span class="genmed"><b>onnod wrote:</b></span></td></tr>
    <tr><td class="quote">Hmm this could do something to the friction i also experience <img src="http://illiweb.com/fa/i/smiles/icon_scratch.png" alt="scratch" longdesc="33">
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    <span class="postbody"><br>yes it eliminates the friction nearby the fork ... rubber with wood tend to stick (even well polished) but rubber with polished round steel slip evenly ...</span>
     
  8. onnod

    onnod Im from Holland, isnt that weird?

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    Sounds good, you are quite the improver; first the double taper, the rods and now this
     
  9. Arturo Borquez

    Arturo Borquez Administrator

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    maybe this view is better ... you can see the clearance between the rubber and the fork tip ...<br>[​IMG]
     
  10. tokSick

    tokSick Senior Member

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    Hi Arturo,<br>Seems like you have a point there. It can be that it helps for accuracy too imo, because of less bands friction the shot fly more strait... Don' t really know... Give us your impressions please. Great idea man!!
     
  11. onnod

    onnod Im from Holland, isnt that weird?

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    Just by the way, you can also increase accuracy by making the tips hollow like this _/, ofcourse this is a bit too much but i don't have paint on my phone.
     
  12. Arturo Borquez

    Arturo Borquez Administrator

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    <table width="90%" cellspacing="1" cellpadding="0" border="0" align="center">
    <tr><td><span class="genmed"><b>onnod wrote:</b></span></td></tr>
    <tr><td class="quote">Just by the way, you can also increase accuracy by making the tips hollow like this _/, ofcourse this is a bit too much but i don't have paint on my phone.</td></tr>
    </table>
    <span class="postbody"><br>GOOD POINT !!! Onnod ... I will try it ...</span>
     
  13. Arturo Borquez

    Arturo Borquez Administrator

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    <table width="90%" cellspacing="1" cellpadding="0" border="0" align="center">
    <tr><td><span class="genmed"><b>tokSick wrote:</b></span></td></tr>
    <tr><td class="quote">Hi Arturo,<br>Seems like you have a point there. It can be that it helps for accuracy too imo, because of less bands friction the shot fly more strait... Don' t really know... Give us your impressions please. Great idea man!!</td></tr>
    </table>
    <span class="postbody"><br>Hi tokSick ... I guess that helps to have less "ripple" on the band during the early acceleration stages of the ammo ... imo the bands are more quieter now !!! ...</span>
     
  14. Arturo Borquez

    Arturo Borquez Administrator

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    as I shoot sideways and now the fork is slippery I've made a calculus of the "normal drop" of the ammo during acceleration and it is almost negligible,<br>with a 14milliseconds bands contraction time:<br><br>drop=0.5*g*t*t <br><br>0.5*9.81*0.014*0.014 = 0.00096138 (1mm aprox) with 1meter draw (me)<br><br>0.001/1000 ~ 10e-6 degrees, so hollowing the "rests" it seems to be unnecessary ... <br><br>it would be the same as the auto-centering arrangements ...
     
  15. pelleteer

    pelleteer Middle Aged Delinquent

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    That's a really cool idea. I bet a similar setup using PTFE (Teflon) rods would be even slicker. <img src="http://illiweb.com/fa/i/smiles/icon_cool.gif" alt="Cool" longdesc="6">
     
  16. JoergS

    JoergS Administrator

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    Looks cool, but if you really want to prevent abbrasion it would be better to move the rod to the end of the fork tip, as close to the rubber attachment as possible. <br><br>Otherwise the rubber will move over the rods, under full strain, which WILL cause abbrasion. <br><br>And of course the rods have to be polished to a glass like surface.
     
  17. Arturo Borquez

    Arturo Borquez Administrator

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    <table width="90%" cellspacing="1" cellpadding="0" border="0" align="center">
    <tr><td><span class="genmed"><b>JoergS wrote:</b></span></td></tr>
    <tr><td class="quote">Looks cool, but if you really want to prevent abbrasion it would be better to move the rod to the end of the fork tip, as close to the rubber attachment as possible. <br><br>Otherwise the rubber will move over the rods, under full strain, which WILL cause abbrasion. <br><br>And of course the rods have to be polished to a glass like surface. </td></tr>
    </table>
    <span class="postbody"><br>Yes, your are correct, but because of structural issues (plywood) and attachment system I couldn't do it more close ... anyway the typical low band scratches disappeared, only a narrow black stain nearby attachment ...</span>
     
  18. onnod

    onnod Im from Holland, isnt that weird?

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    Maybe you can make some sort of sock that you can slide on..
     
  19. zwillie

    zwillie New Member

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    Hi Arturo,<br>I would polish the rods.<br>Some toothpaste on a leather strip and then rub the forkends over it.<br>Works fine.
     
  20. Arturo Borquez

    Arturo Borquez Administrator

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    <table width="90%" cellspacing="1" cellpadding="0" border="0" align="center">
    <tr><td><span class="genmed"><b>zwillie wrote:</b></span></td></tr>
    <tr><td class="quote">Hi Arturo,<br>I would polish the rods.<br>Some toothpaste on a leather strip and then rub the forkends over it.<br>Works fine.</td></tr>
    </table>
    <span class="postbody"><br>fine ... also have car polishing wax and silver polisher (smells ammonia), among these what is the best to avoid a chemical attack to the plywood ??</span>