[v2] Prusa i3 MK3 Y-axis belt tensioner

prusaprinters

<p>This is a remix of the y-axis idler mount from the <a href="https://github.com/gregsaun/prusa_i3_bear_upgrade">Prusa i3 Bear Upgrade</a> that fits on the stock Prusa i3 MK3 frame.</p><h3>Installation</h3><ol><li>Remove the LCD assembly from the front plate</li><li>Remove the front plate and existing idler mount from the printer</li><li>Screw the new y idler mount onto the front plate using the <strong>top</strong> and <strong>bottom</strong> holes</li><li>Drill through the <strong>middle</strong> hole using a 3mm (or 1/8in) bit to make a new mounting hole in the front plate (deburr if necessary)</li><li>Remove the mount and place the final installation hardware<ol><li>Install regular hex nuts into the <strong>bottom</strong> and <strong>middle</strong> holes</li><li>Install a nylock nut (nylon side <i>towards</i> the front plate) into the<i><strong> </strong></i><strong>top </strong>hole</li></ol></li><li>Being careful not to lose the nylock nut, pass screws through the front plate into the mount using the <strong>bottom</strong> and <strong>middle</strong> holes</li><li>Attach the tensioner to the idler mount using an M3×25mm screw and nylock nut</li><li>If you have a MK3S(+), replace the tensioner under the bed with a MK3 belt clamp</li></ol><p>Installation for v1 is similar, but alignment is more difficult and you need to insert the nylock nut into the slot on top.</p><h3>v2 Update</h3><ul><li>Loosen nut tolerances</li><li>Tensioner nut is now held in place by the frame; no need to push it in from the top</li></ul><p><strong>Note: </strong>the images are of v1, but the process for v2 is similar.</p><h3>Required Parts</h3><figure class="table"><table><tbody><tr><td><a href="https://media.printables.com/media/prints/88240/stls/932039_2b9136b1-beed-4333-a90e-361ab2e47dca/y-belt-holder.stl">Original MK3 belt holder</a></td><td>Print this if you have a MK3S(+). Having two tensioners for the same belt may be problematic.</td></tr><tr><td><a href="https://github.com/gregsaun/prusa_i3_bear_upgrade/blob/master/printed_parts/common_to_all_versions/stl/y_idler_tensioner.stl">Prusa smooth idler tensioner</a></td><td>Print this if you have the stock Prusa idler, 3mm bore with a single bearing.</td></tr><tr><td><a href="https://github.com/gregsaun/prusa_i3_bear_upgrade/tree/master/optional_parts/y_idler_tensioner_e3d">E3D toothed idler tensioner</a></td><td>Print this if you have an <a href="https://e3d-online.com/products/gates-powergrip%C2%AE-2gt-idlers">E3D 20-toothed idler for 6mm 2GT belts</a>. Toothed idlers have several benefits over smooth idlers (see E3D's description).</td></tr></tbody></table></figure><h3>Printing Instructions</h3><p>Print with 3 or 4 perimeters and at least 20% infill using a 0.4mm nozzle. Although it works either way, I recommend printing this model upside down to put the nice surface finish on top.</p>