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

  • Shoulder PT Pulley: Last 10% Manufacturing

    Mary’s PT requires a Shoulder Pulley, so I got one that seemed better constructed than the cheapest Amazon crap. In particular, this view suggested the pulley ran on a bearing:

    Slim Panda Shoulder Pulley - detail view
    Slim Panda Shoulder Pulley – detail view

    Which turned out to be the case, but, also as expected, the whole thing required a bit of finishing before being put in service.

    It’s intended to hang from a strap trapped between an interior door and its frame. The strap was intended to attach to the block (a.k.a. “Thickened base”) through a breathtakingly awkward pair of low-end carabiners:

    Slim Panda Shoulder Pulley - carabiners
    Slim Panda Shoulder Pulley – carabiners

    Which I immediately replaced with a simple, silent, sufficiently strong black nylon cable tie:

    Shoulder PT Pulley - block hardware
    Shoulder PT Pulley – block hardware

    Rather than let the metal block clunk against the door, it now sports a pair of cork-surfaced bumper plates:

    Shoulder PT Pulley - side plates installed
    Shoulder PT Pulley – side plates installed

    A doodle of the block dimensions:

    Shoulder Pulley - dimension doodle
    Shoulder Pulley – dimension doodle

    Which turned into a simple LightBurn layout:

    Shoulder PT Pulley Side Plates - LB layout
    Shoulder PT Pulley Side Plates – LB layout

    The blue construction lines represent the actual block & pulley, with the red cut lines offset 2 mm to the outside to ensure the metal stays within the bumpers. It’s possible to pick the block up and whack the pulley against the door, so don’t do that.

    Cut out two pieces of 3 mm MDF, two pieces from a cork coaster (covered with blue tape and cut with the paper backing up), peel-n-stick the cork to the MDF, put double-sided foam tape on the block, peel-n-stick the bumpers, then hang on the attic door.

    Now it works the way it should!

    The LightBurn SVG layout as a GitHub Gist:

    Loading
    Sorry, something went wrong. Reload?
    Sorry, we cannot display this file.
    Sorry, this file is invalid so it cannot be displayed.