Multi-Grain Burr - Assembly puzzle by Stewart Coffin (STC #275-A)

prusaprinters

<h3>Multi-Grain Burr</h3><h4>Assembly puzzle by Stewart Coffin (STC #275-A)</h4><p>Assemble the four pieces into the unusual shape shown in the photo.</p><p><i>Multi-Grain Burr</i> is surprisingly difficult despite having only four pieces, due to the unusual shape of the assembly. It is a larger variant of Coffin's <a href="https://www.printables.com/model/171107">Three-Piece Block</a>; if you're unfamiliar with this type of puzzle, I'd recommend starting with <i>Three-Piece Block</i> instead.</p><h4>Printing Instructions</h4><p>Print one copy of <code>coffin.coffin.multi-grain-burr.pieces.stl</code>. This model uses snap joints so that the pieces can be printed without supports; for this particular puzzle, I recommend using a sturdy PLA filament (or something stronger, such as PLA+ or ABS) and/or reinforcing with glue, due to the fragile nature of some of the joints.</p><p>Coffin specified that the "key piece" (the piece made from just two cubes) be made tight, so that it is less obvious how to <i>disassemble</i> the puzzle once it's assembled. If you find that the key piece does not hold firmly in place, you can try printing <code>coffin.coffin.multi-grain-burr.tighter-key-piece.stl</code> as a replacement. (I didn't want to make the tighter version the default, because printer tolerances vary.)</p><p>After you print it, first connect all the joints before attempting to solve the puzzle. Snap each male connector into a corresponding female connector (for example, the male connector labeled "A" should connect to the female connector with a matching "A" label on the interior).</p><p>The joints are designed to be tight, and depending on the printer and filament used, you may need to hammer them into place. If they come out too loose, a drop of superglue will make them more solid (in most cases this shouldn't be necessary, but unfortunately tolerances vary across printers and filaments). The snap joint concept is discussed further in this tutorial: <a href="https://www.puzzlehub.org/tutorials/getting-started">Getting Started with Puzzle Printing</a>.</p><p>For a slightly smaller version that uses less material, you can print <code>coffin.coffin.multi-grain-burr.pieces-smaller.stl</code> instead (and, optionally, <code>coffin.coffin.multi-grain-burr.tighter-key-piece-smaller</code>.</p><h4>The Printable Puzzle Project</h4><p>The <a href="https://www.puzzlehub.org/ppp">Printable Puzzle Project</a> aims to make available high-quality open-source models of many puzzle designs. All of our models are posted with the generous permission of their designers and are licensed for <strong>non-commercial use only</strong>. Anyone may print copies for their own personal use, but selling or otherwise monetizing them is not permitted, and puzzle designers retain all rights as copyright holders of their work.</p><p>Our puzzles are modeled using the open-source <a href="https://www.puzzlehub.org/puzzlecad">puzzlecad</a> library. The <code>.scad</code> file is included with this model in case you want to modify any of its design parameters; more information on how to do this can be found in the PPP <a href="https://www.puzzlehub.org/tutorials/puzzle-modeling">Puzzle Modeling tutorial</a>.</p><h4>About the Designer</h4><p>Stewart Coffin has been called "the most outstanding designer and maker of interlocking puzzles that the world has ever seen". He is credited with over four hundred designs, has pioneered numerous ingenious puzzle forms, and has written extensively about puzzle design and craftsmanship. More information on Coffin, along with many other printable models of his designs, can be found on the <a href="https://www.puzzlehub.org/puzzles/stewart-coffin">Stewart Coffin Puzzles</a> overview page.</p><p>Happy puzzling!</p>