Copymaster 3D 500 bed levelling knobs

thingiverse

Bed levelling during the start of a print has become a breeze thanks to these new, larger knobs. The original small grey knobs made it awkward, but these bigger ones have simplified the process entirely. The heated bed cable needs to be re-routed under the Y axis instead of going over the new knobs, which would cause interference. This requires unplugging the cable from the mainboard, a relatively simple task that involves removing a cover exposing mains electricity. It's essential to unplug the printer from the mains first and be aware of any warranty implications. If you're not comfortable with this process, consider replacing three knobs instead. These new knobs are quite skinny (3.4mm), which means they can easily foul the Y axis rails. The centre boss containing the nuts protrudes an additional 3mm, while the diameter is a generous 112mm - large enough to avoid interfering with the Y axis limit switch. To secure these knobs to the bed frame, you'll need to use a thin steel washer (less than 1mm thick). I've included a printable washer design in this text. It's 18mm in diameter and has a 4mm hole, but feel free to scale it up or down for different thicknesses. In my case, I used clear molded plastic packaging material, which worked surprisingly well. I initially printed a washer with an integrated spacer, but that required printing with supports, resulting in a poor-quality surface finish. Each knob takes two M3 nuts (5.5mm across the flats), and the thread pitch is 0.5mm. With 15 outer spokes on each knob, it's easy to adjust the bed by precise increments - three spokes equal 0.1mm. To ensure accurate placement of the nuts, I tapped them onto a bolt before fitting them to the printer. When printing these knobs, place the boss section uppermost and avoid using supports. I printed mine in PLA, but higher-temperature filaments might be more suitable given their proximity to the heated bed and skinny design.