Shifter Cable Downtube Stop

prusaprinters

<p><a href="http://www.wiggle.com/shimano-sti-pair-of-cable-stops/">http://www.wiggle.com/shimano-sti-pair-of-cable-stops/</a></p> <p>Save yourself money &amp; don't spend $10-20 on these. They're not worth it.</p> <p>Designed for 1.125" downtubes. This seems to a very common steel tubing size. My bike is from the 1980s, &amp; it works fine. I imagine you could use a round file to bring it to a better fit if you need.</p> <h3>How I Designed This</h3> <p>Based on Shimano downtube cable stops.</p> <p>I moved the barrel adjuster axis further out to accommodate large diameter barrel adjusters. The ones that come with the Shimano stops are small &amp; hard to grip, &amp; if you use larger diameter adjusters, then they're hard to grip because they're too close to the downtube.</p> <p>The face with the barrel adjuster has little indents cut out to index with the notches on Shimano barrel adjusters (<a href="http://www.chainreactioncycles.com/us/en/shimano-rear-mech-barrel-adjuster/rp-prod8620">http://www.chainreactioncycles.com/us/en/shimano-rear-mech-barrel-adjuster/rp-prod8620</a>). I approximated these since they're almost impossible to measure, so best of luck if they work.</p> <p>The captive nut is set in very deep, since I designed it for one approximately 5 mm in height, &amp; the max exposed thread on the barrel adjuster is about 8.04 mm, so the thickness between the barrel adjuster face &amp; the nut face must be around 3 mm.</p> <p>This will definitely limit the amount of adjustment available, but it's a necessary consequence of not being able to thread the 3D printed material.</p> <p>Forewarning on the SLDPRT: I accidentally created the barrel adjuster extrusion perpendicular to the downtube axis. I fixed this by deleting the downtube cut-extrude, then re-cut extruding in the correct direction. This broke a reference in the barrel adjuster extrusion sketch, &amp; I thought I fixed it, but Solidworks still says it's underdefined. I don't know why, but it's still building correctly, so I gave up after about 5 minutes of trying to fix it.</p> <h3>Assembly &amp; Materials</h3> <p>You'll need a barrel adjuster. Cannibalize one from an old RD.</p> <p>The Shimano cable stops come with buttonhead screws, 10.28 mm long, 4.89 mm total outside thread diameter. Something around that size should work. The buttonheads have a nice transition with the rest of the cover.</p> <p>You will also need a 4 mm nut, will fit 99% of heights since the captive depth is very deep. You could use a locknut, but I'm not sure how tight it might be to turn.</p> <p>Ready for 3D printing (no machining version).</p> <p>Use a round file to bring it to a better fit if you need.</p> <h3>Updates</h3> <p>17 Jan 17: Did a test print with 0.1 mm layer height, 3.0 mm HIPS on a Lulzbot Mini. The recesses for the barrel adjuster didn't render, but the curvature for the downtube was dead on perfect. I just need to test the fit over a shifter boss. Another concern: the recess for the nut is very close to the perimeter. I think it'll be okay, but it just looks really damn close.</p> <p class="detail-video"> <figure class="media"> <oembed url="https://www.youtube.com/embed/SJJyl0xPrJ0?t=531"></oembed> </figure> </p> Category: Replacement Parts