{"product_id":"ratchet-educational-model","title":"Ratchet - Educational model","description":"\u003ch2\u003eMy Educational Mechanical Examples Series\u003c\/h2\u003e\u003cp\u003eThis model is one of my educational mechanical mechanism examples on 80mm x 80mm base plates.\u003cbr\u003eYou can find all models of the series in this collection =\u0026gt; \u003ca target=\"_blank\" rel=\"noopener noreferrer ugc\" href=\"https:\/\/makerworld.com\/collections\/15048577-my-educational-mechanism-models\"\u003e[Mechanical Mechanism Examples]\u003c\/a\u003e\u003c\/p\u003e\u003cfigure class=\"image image_resized\" style=\"width: 61.78%\"\u003e\u003cimg src=\"https:\/\/makerworld.bblmw.com\/makerworld\/model\/DSM00000002058683\/design\/2025-11-13_a0fbbb25e21458.png\"\u003e\u003c\/figure\u003e\u003ch2\u003eThis model\u003c\/h2\u003e\u003cp\u003eThis is an educational model of a \u003ci\u003espring-free\u003c\/i\u003e ratchet mechanism which does not cause large click noise when it freewheels.\u003c\/p\u003e\u003cp\u003e \u003c\/p\u003e\u003cp\u003eTurning the central disc clockwise drives the outer ring, while turning it counterclockwise makes the ratchet freewheel.\u003c\/p\u003e\u003cp\u003e \u003c\/p\u003e\u003cfigure class=\"image\"\u003e\u003cimg src=\"https:\/\/makerworld.bblmw.com\/makerworld\/model\/DSM00000002058683\/design\/2ba00d3f-573b-4a1a-8687-af49840991a9.webp\"\u003e\u003c\/figure\u003e\u003cp\u003e\u003cimg class=\"image_resized\" style=\"width: 47.74%\" src=\"https:\/\/makerworld.bblmw.com\/makerworld\/model\/DSM00000002058683\/design\/2025-12-04_e4096c1e8178f.gif\"\u003e\u003cimg class=\"image_resized\" style=\"width: 47.75%\" src=\"https:\/\/makerworld.bblmw.com\/makerworld\/model\/DSM00000002058683\/design\/2025-12-04_85d9c6b8accc88.gif\"\u003e\u003c\/p\u003e\u003cp\u003e \u003c\/p\u003e\u003cfigure class=\"media\"\u003e\u003coembed url=\"https:\/\/www.youtube.com\/watch?v=DIjd3Ipg6gA\"\u003e\u003c\/oembed\u003e\u003c\/figure\u003e\u003cp\u003e \u003c\/p\u003e\u003ch2\u003eBrief description\u003c\/h2\u003e\u003cp\u003eGenerally speaking, a ratchet mechanism is used to allow rotation in only one direction, preventing reverse motion.\u003c\/p\u003e\u003cp\u003e \u003c\/p\u003e\u003cp\u003eIn this model, the ratchet works between two rotational elements: the central disk acts as the input, and the outer ring serves as the output.\u003c\/p\u003e\u003cp\u003eWhen the input disk is rotated clockwise, the ratchet prevents relative motion between the two parts. As a result, the output ring rotates together with the input.\u003c\/p\u003e\u003cp\u003e \u003c\/p\u003e\u003cp\u003eOn the other hand, when the input is rotated counterclockwise, the ratchet allows the input disk to freewheel, and the output ring does not rotate.\u003c\/p\u003e\u003cp\u003e \u003c\/p\u003e\u003cp\u003eSimilar mechanisms are widely used in devices such as bicycles and wrenches.\u003c\/p\u003e\u003cp\u003e \u003c\/p\u003e\u003cp\u003eIn many ratchet systems, the \u003cstrong\u003epawls—small claw-like pieces that engage with the teeth—\u003c\/strong\u003e are pressed against the ratchet wheel by \u003ci\u003esprings\u003c\/i\u003e. In this model, however, the ratchet action is achieved solely by the carefully designed shape of these pawls, without relying on springs. Thanks to it, it does not cause large click noise when it freewheels.\u003c\/p\u003e\u003ch3\u003eReference(s)\u003c\/h3\u003e\u003cul\u003e\u003cli\u003e\u003ca target=\"_blank\" rel=\"noopener noreferrer ugc\" href=\"https:\/\/karakurist.jp\/?p=49\"\u003ehttps:\/\/karakurist.jp\/?p=49\u003c\/a\u003e\u003c\/li\u003e\u003c\/ul\u003e\u003ch2\u003eCase\u003c\/h2\u003e\u003cp\u003eThis model is compatible with the case included \u003ca target=\"_blank\" rel=\"noopener noreferrer ugc\" href=\"https:\/\/makerworld.com\/models\/1983088-educational-gear-examples-1\"\u003ein my first set\u003c\/a\u003e.\u003c\/p\u003e\u003cfigure class=\"image\"\u003e\u003cimg src=\"https:\/\/makerworld.bblmw.com\/makerworld\/model\/DSM00000002058683\/design\/2025-11-14_92d0e04758acd.jpg\"\u003e\u003c\/figure\u003e\u003ch2\u003ePrinting\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eUse the models named \u003ci\u003e\u003cstrong\u003e???-printable.stl \u003c\/strong\u003efor printing\u003cstrong\u003e.\u003c\/strong\u003e\u003c\/i\u003e\u003cbr\u003eThe models named \u003ci\u003e\u003cstrong\u003e???-assembled.stl\u003c\/strong\u003e\u003c\/i\u003e are provided just to show how they should be assembled.\u003cbr\u003e \u003c\/li\u003e\n\u003cli\u003eUse \u003cstrong\u003ewell-dried PETG\u003c\/strong\u003e to have better dimensional accuracy.\u003c\/li\u003e\n\u003cli\u003eUse \u003cstrong\u003e0.1 mm or 0.08 mm layer height\u003c\/strong\u003e to have smoother surfaces.\u003c\/li\u003e\n\u003cli\u003eUse slow printing speed for overhangs.\u003c\/li\u003e\n\u003cli\u003eSelect \u003cstrong\u003e“Random” seam position\u003c\/strong\u003e to have smoother rotation.\u003cbr\u003eRandomly distributed seam should be easily worn out after some wearing.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eSanding and Filing\u003c\/h2\u003e\u003cp\u003eSometimes, the gears suffer from the stringing effect and\/or elephant foot effect, resulting in a too tight fit to the shafts (they are designed with a 0.15 mm radial clearance). \u003c\/p\u003e\u003cp\u003eIf you see rough surface on the shafts due to stringing, sand off the roughness with a small piece of sand paper.\u003c\/p\u003e\u003cp\u003e\u003cimg class=\"image_resized\" style=\"width: 32.08%\" src=\"https:\/\/makerworld.bblmw.com\/makerworld\/model\/DSM00000002058683\/design\/e3abfcd0-e7ad-4abe-85e6-6965ba474fb3.webp\"\u003e\u003cimg class=\"image_resized\" style=\"width: 31.94%\" src=\"https:\/\/makerworld.bblmw.com\/makerworld\/model\/DSM00000002058683\/design\/fa3a3254-6dd2-4e30-8dd5-2a9c7d5bf1bf.webp\"\u003e\u003cimg class=\"image_resized\" style=\"width: 31.92%\" src=\"https:\/\/makerworld.bblmw.com\/makerworld\/model\/DSM00000002058683\/design\/b5710942-b209-4c4f-9808-6e8e106c0771.webp\"\u003e\u003c\/p\u003e\u003cp\u003eIf you feel the gears do not rotate smoothly due to an elephant effect, widen the hole slightly by using a thin round bar file.\u003c\/p\u003e\u003cfigure class=\"image image_resized\" style=\"width: 75%\"\u003e\u003cimg src=\"https:\/\/makerworld.bblmw.com\/makerworld\/model\/DSM00000002058683\/design\/432ebfa1-c26a-49fd-9ca8-d199382cd692.webp\"\u003e\u003c\/figure\u003e\u003cp\u003eWithout those issues, the parts should rotate very smoothly with minimal friction.\u003c\/p\u003e\u003ch2\u003eAssembly\u003c\/h2\u003e\u003cp\u003eAll parts can be snap assembled.\u003c\/p\u003e\u003cp\u003e \u003c\/p\u003e\u003ch2\u003eOther educational models\u003c\/h2\u003e\u003cp\u003eYou may also be interested in the models in my educational mechanical mechanism examples.\u003c\/p\u003e\u003cp\u003eFind them in this collection:\u003cbr\u003e\u003ca target=\"_blank\" rel=\"noopener noreferrer ugc\" href=\"https:\/\/makerworld.com\/collections\/15048577-my-educational-mechanism-models\"\u003ehttps:\/\/makerworld.com\/collections\/15048577-my-educational-mechanism-models\u003c\/a\u003e\u003c\/p\u003e\u003cfigure class=\"image image_resized\" style=\"width: 61.78%\"\u003e\u003cimg src=\"https:\/\/makerworld.bblmw.com\/makerworld\/model\/DSM00000002058683\/design\/2025-11-13_a0fbbb25e21458.png\"\u003e\u003c\/figure\u003e\u003ch2\u003eAcknowledgement\u003c\/h2\u003e\u003cp\u003eI got into gears thanks to \u003cstrong\u003eK.$uzuki\u003c\/strong\u003e's amazing \u003ca target=\"_blank\" rel=\"noopener noreferrer ugc\" href=\"https:\/\/karakurist.jp\/\"\u003earticles\u003c\/a\u003e and \u003ca target=\"_blank\" rel=\"noopener noreferrer ugc\" href=\"https:\/\/www.youtube.com\/@karakurist\"\u003eYouTube videos\u003c\/a\u003e. Many of the mechanisms shown in this series came from the introductions on \u003ca target=\"_blank\" rel=\"noopener noreferrer ugc\" href=\"https:\/\/karakurist.jp\/\"\u003ehis website\u003c\/a\u003e. He also makes \u003ca target=\"_blank\" rel=\"noopener noreferrer ugc\" href=\"https:\/\/oishiiosushi.thebase.in\/\"\u003eexcellent gear models\u003c\/a\u003e himself. This series wouldn’t have existed without his inspiration.\u003c\/p\u003e\u003cp\u003eI learned a lot about technical detail of designing gear tooth profiles from \u003ca target=\"_blank\" rel=\"noopener noreferrer ugc\" href=\"https:\/\/involutegearsoft.hatenablog.com\/\"\u003eHaguruma-No-Hanashi website\u003c\/a\u003e. I’m truly grateful for that.\u003c\/p\u003e\u003cp\u003e \u003c\/p\u003e\u003ch2\u003eLicense (2026-03-13 updated)\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eThe 3D model(s) are licensed under \u003ca target=\"_blank\" rel=\"noopener noreferrer ugc\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\"\u003eCreative Commons Attribution 4.0 International\u003c\/a\u003e. (unchanged)\u003c\/li\u003e\n\u003cli\u003eHowever, the text and images on this page are copyright reserved. (added on 2026-03-13)\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e \u003c\/p\u003e\u003cp\u003eDesign by osamutake on MakerWorld (license: BY).\u003c\/p\u003e","brand":"Mymadmanlab","offers":[{"title":"Default Title","offer_id":67391423840560,"sku":null,"price":6.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0987\/0809\/5280\/files\/0_a7a80995-6707-4043-a190-fc9558b410e2.png?v=1784750792","url":"https:\/\/mymadmanlab.com\/products\/ratchet-educational-model","provider":"Mymadmanlab.com","version":"1.0","type":"link"}