Prusa MK3 Bear Full Upgrade length-adjustable X idler

prusaprinters

<p>Rework of the stock MK3 R3 X idler which allows +/- 1mm of rod length adjustment. The final length is locked in place using two M3x8 screws.</p> <p>Only valuable for custom builds, such as the full bear upgrade. This is unlikely to be useful for the plain MK3 or the bear half-upgrade.</p> <p>I noticed the Z screws were simultaneously flexing in opposing directions when going full up or down, a sign of rod-length mismatch for your assembly. Note: if they displace in random directions then rod-length is<em>not</em> an issue (release tension from the POM nuts, if any, then check again).</p> <p>If the screws don't touch the hole in the Z tops you're still fine. But now that you noticed your OCD will kick-in and deep down you<em>know</em> you'll have to fix it: we're not here for "good enough".</p> <p>Print at 0.2mm with 0.1 for the first layer (this improves rod center alignment) or at 0.3mm through-out. Use 3 perimeters at 30% grid infill. Ram the holes with a 8mm drill. Check and clean any debris, especially in the pockets.</p> <p>Insert the M3x8 screws, which will self-tap the holes. Keep moving the screws until they don't squeak anymore: you'll need some feel while tightening later.</p> <p>Insert the rods and push them<em>fully</em>. The assembly should be 1mm shorter than stock length. Tighten the screws until you feel some tension due to the rods touching. Insert the assembly into the Z screws/rods. Insert the Z tops to align the POM nuts and tighten them, but do<em>not</em> tighten the Z tops yet. Move the carriage fully down and watch the direction of the Z screws: if they go inwards rotate 1/4 turn of both screws and repeat by moving the carriage up and down again.</p> <p>Go slowly: if the screws start to go outwards the rods are too long. Due to the fit of the X rods it's not possible to easily shorten the carriage. Remove the assembly and push the rods fully back in before trying again.</p> Category: 3D Printer Parts