The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

The New Hotness

  • MPCNC: Acrylic Engraving First Light

    Just to see what happened, I chucked a drag knife in the collet pen holder:

    MPCNC Collet Pen Holder - drag knife
    MPCNC Collet Pen Holder – drag knife

    The blade, being fixed in the collet and lashed to the adapter, doesn’t rotate: it’s not behaving as a true drag knife.

    Twiddling the cut depth to about 0.2 mm produced a credible Guilloché pattern in some scrap acrylic:

    MPCNC Collet Pen Holder - drag engraved acrylic - 0.2 mm depth
    MPCNC Collet Pen Holder – drag engraved acrylic – 0.2 mm depth

    The sidelight comes from an LED flashlight off to the side, with a bit of contrast tweaking to suppress the workbench clutter.

    The MPCNC’s lack of rigidity produces visible jitters in the Guilloché pattern and backlash makes the characters somewhat wobbly, but it’s OK for a large and inexpensive CNC gantry machine.

    A brace of diamond-point engraving bits are making their way around the planet even as I type. A symmetric 60° point may reduce the swarf thrown out by the drag knife, although it surely won’t improve the overall jitter and backlash.