{"product_id":"educational-gear-examples-2","title":"Educational Gear Examples 2","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\/DSM00000001983808\/design\/2025-11-13_a0fbbb25e21458.png\"\u003e\u003c\/figure\u003e\u003ch2\u003eThis set\u003c\/h2\u003e\u003cp\u003eThis present set includes:\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eHelical Rack\u0026amp;Pinion\u003c\/li\u003e\n\u003cli\u003eHelical Internal Gear\u003c\/li\u003e\n\u003cli\u003eSpiral Bevel Gear\u003c\/li\u003e\n\u003cli\u003eMulti-Threaded Worm with Worm Wheel\u003c\/li\u003e\n\u003cli\u003eHelical Crown Gear\u003c\/li\u003e\n\u003cli\u003eGeneva Drive\u003c\/li\u003e\n\u003cli\u003eArchimedean Spiral Gear\u003c\/li\u003e\n\u003cli\u003eIntermittent gear\u003c\/li\u003e\n\u003c\/ul\u003e\u003cfigure class=\"image\"\u003e\u003cimg src=\"https:\/\/makerworld.bblmw.com\/makerworld\/model\/DSM00000001983808\/design\/614bd31e-d4bb-400c-b3a0-bc21a0b7c301.webp\"\u003e\u003c\/figure\u003e\u003cfigure class=\"image\"\u003e\u003cimg src=\"https:\/\/makerworld.bblmw.com\/makerworld\/model\/DSM00000001983808\/design\/cfdd8fc0-ebe5-4ae8-973d-f99f66e08f8b.gif\"\u003e\u003c\/figure\u003e\u003cp\u003e \u003c\/p\u003e\u003cp\u003eWorm \u0026amp; Worm wheel, Bevel, Rack \u0026amp; pinion, Crown and Internal gears are also included in \u003ca target=\"_blank\" rel=\"noopener noreferrer ugc\" href=\"https:\/\/makerworld.com\/models\/1983088-educational-gear-examples-1\"\u003emy first set of educational examples\u003c\/a\u003e, but this model provides \u003ci\u003e\u003cstrong\u003ehelical or\u003c\/strong\u003e\u003c\/i\u003e \u003ci\u003e\u003cstrong\u003espiral \u003c\/strong\u003e\u003c\/i\u003evariations of Bevel, Rack \u0026amp; pinion, Crown and Internal gears, and \u003ci\u003e\u003cstrong\u003emultiple threaded variation\u003c\/strong\u003e\u003c\/i\u003e (two, three, and four threads) of Worm \u0026amp; Worm wheel.\u003c\/p\u003e\u003cp\u003e\u003cimg class=\"image_resized\" style=\"width: 37.44%\" src=\"https:\/\/makerworld.bblmw.com\/makerworld\/model\/DSM00000001983808\/design\/b6e51029-8429-4f14-8878-8b51e5de8089.webp\"\u003e\u003cimg class=\"image_resized\" style=\"width: 50%\" src=\"https:\/\/makerworld.bblmw.com\/makerworld\/model\/DSM00000001983808\/design\/9ae738d6-9acb-4131-b803-3a783a1438b7.webp\"\u003e\u003c\/p\u003e\u003cp\u003eThe gears on the upper row are included in this model. Those on the lower row are included in the other model (the first set of the gear examples).\u003c\/p\u003e\u003cp\u003eGeneva, Spiral and Intermittent gears were not included in the first set.\u003c\/p\u003e\u003cp\u003eFlat spur and helical gear, and screw gears are only included in the first set.\u003c\/p\u003e\u003ch2\u003eIntroduction Video\u003c\/h2\u003e\u003cfigure class=\"media\"\u003e\u003coembed url=\"https:\/\/www.youtube.com\/watch?v=2Bc9nVygdHI\"\u003e\u003c\/oembed\u003e\u003c\/figure\u003e\u003cp\u003e \u003c\/p\u003e\u003ch2\u003eBrief Descriptions\u003c\/h2\u003e\u003cp\u003e\u003cimg class=\"image_resized\" style=\"width: 94.02%\" src=\"https:\/\/makerworld.bblmw.com\/makerworld\/model\/DSM00000001983808\/design\/d29bdfbc-72c8-4950-8c05-7d7a3fd296d2.webp\"\u003e\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHelical Rack, Helical Internal gear, Spiral Bevel gear and Helical Crown gear\u003c\/strong\u003e are variations of \u003ca target=\"_blank\" rel=\"noopener noreferrer ugc\" href=\"https:\/\/makerworld.com\/models\/1983088-educational-gear-examples-1\"\u003etheir standard straight-tooth versions that are included in my first set of gear examples\u003c\/a\u003e. Because their teeth engage gradually along the helix or spiral, contact and separation occur progressively during the rotation. This results in smoother meshing and quieter operation compared to gears with straight teeth. These modified gear types are used when smooth motion, low noise, or high-speed rotation is required.\u003c\/p\u003e\u003cp\u003e \u003c\/p\u003e\u003cfigure class=\"image image_resized image-style-align-right\" style=\"width: 22.5%\"\u003e\u003cimg src=\"https:\/\/makerworld.bblmw.com\/makerworld\/model\/DSM00000001983808\/design\/b5e56731-c5db-4653-9309-8a3a07033e4c.png\"\u003e\u003c\/figure\u003e\u003cp\u003e\u003cstrong\u003eMulti-threaded Worm\u003c\/strong\u003e has a larger helix angle than \u003ca target=\"_blank\" rel=\"noopener noreferrer ugc\" href=\"https:\/\/makerworld.com\/models\/1983088-educational-gear-examples-1\"\u003ea single-thread worm that is included in my first set of gear examples\u003c\/a\u003e. This model includes two-, three-, and four-thread worms, which have two, three and four continuous teeth around the cylinder. Because of the high gear ratio, the motion transmission between the worm and worm wheel is usually one-way — the worm can drive the worm wheel, but the worm wheel cannot drive the worm. However, for multi-threaded worms, the gear ratio can be small enough for the worm wheel to drive the worm. When this happens, the one-way motion transmission property no longer holds. Increasing the number of threads makes the worm rotate faster for each turn of the wheel, but reduces the self-locking effect. Therefore, multi-threaded worms are used when efficiency and speed are more important than self-locking.\u003c\/p\u003e\u003cp\u003e \u003c\/p\u003e\u003cfigure class=\"image image_resized image-style-align-right\" style=\"width: 22.77%\"\u003e\u003cimg src=\"https:\/\/makerworld.bblmw.com\/makerworld\/model\/DSM00000001983808\/design\/1cd0d6ad-7d44-4b60-a2d6-3d8e60ff2473.png\"\u003e\u003c\/figure\u003e\u003cp\u003eArchimedean\u003cstrong\u003e Spiral\u003c\/strong\u003e gear is formed by sweeping a rack tooth along an Archimedean spiral curve. When the gear pair is sectioned by a plane containing both axes, the cross-sectional profiles exactly match those of a standard rack and pinion. However, since the spiral teeth are not perpendicular to the radius, the pinion is not a simple spur gear in three dimensions; it is similar to a helical gear. More precisely, the teeth of the pinion are not perfectly helical, but slightly curved to follow the spiral teeth of the mating gear. An Archimedean spiral gear can achieve a very high gear ratio, comparable to that of a worm gear. Because of this, motion is often transmitted in only one direction — that is, from the spiral gear to the pinion, but not in the other way around. The Archimedean is chosen when spatial constraints make it more suitable than a worm gear.\u003c\/p\u003e\u003cp\u003e \u003c\/p\u003e\u003cp\u003e \u003c\/p\u003e\u003cfigure class=\"image image_resized image-style-align-right\" style=\"width: 22.77%\"\u003e\u003cimg src=\"https:\/\/makerworld.bblmw.com\/makerworld\/model\/DSM00000001983808\/design\/7d94cb11-05ab-41d3-bb19-06e6570a80cd.png\"\u003e\u003c\/figure\u003e\u003cp\u003e\u003cstrong\u003eIntermittent\u003c\/strong\u003e gear transmits the motion only during a portion of its rotation and \u003ci\u003elocks the other gear\u003c\/i\u003e during the rest of the cycle. In this model, both of the driving and driven gears consist of two layers: the upper layer transmits the motion, while the lower layer locks the driven gear while the motion is not being transmitted. With this design, the velocity of the driven gear increases and decreases discontinuously, starting and stopping abruptly. Therefore, this type of gear is not suitable for heavy loads or high-speed applications.\u003c\/p\u003e\u003cp\u003e \u003c\/p\u003e\u003cp\u003e \u003c\/p\u003e\u003cp\u003e \u003c\/p\u003e\u003cp\u003e \u003c\/p\u003e\u003cfigure class=\"image image_resized image-style-align-right\" style=\"width: 23.04%\"\u003e\u003cimg src=\"https:\/\/makerworld.bblmw.com\/makerworld\/model\/DSM00000001983808\/design\/36f3546b-b85c-45c8-9393-49b48f3f1548.png\"\u003e\u003c\/figure\u003e\u003cp\u003e\u003cstrong\u003eGeneva\u003c\/strong\u003e drive, which is also called a Maltese cross mechanism, is another type of intermittent rotation transmission mechanism. In this mechanism, motion is transmitted by a pin that runs inside a radial slot, while the driven gear wheel is locked by cylindrical slipping contact during the rest of the rotation. Compared with the previous partial-involute gear design, the Geneva drive provides smoother acceleration and decelation of the driven wheel, from and to zero velocity. This reduces vibration, noise, and wear on the mechanism.\u003c\/p\u003e\u003cp\u003eThese intermittent mechanisms are used when stepwise or timed motion is required, such as in film projectors, indexing tables, and mechanical clocks.\u003c\/p\u003e\u003cp\u003e \u003c\/p\u003e\u003ch3\u003eReferences\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eSpiral gear \u003ca target=\"_blank\" rel=\"noopener noreferrer ugc\" href=\"https:\/\/karakurist.jp\/?p=2149\"\u003ehttps:\/\/karakurist.jp\/?p=2149\u003c\/a\u003e \u003c\/li\u003e\n\u003cli\u003eIntermittent \u003ca target=\"_blank\" rel=\"noopener noreferrer ugc\" href=\"https:\/\/karakurist.jp\/?p=85\"\u003ehttps:\/\/karakurist.jp\/?p=85\u003c\/a\u003e \u003c\/li\u003e\n\u003cli\u003eGeneva drive \u003ca target=\"_blank\" rel=\"noopener noreferrer ugc\" href=\"https:\/\/karakurist.jp\/?p=21\"\u003ehttps:\/\/karakurist.jp\/?p=21\u003c\/a\u003e \u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eCase\u003c\/h2\u003e\u003cp\u003eThese models are 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\/DSM00000001983808\/design\/1d83445c-2106-4ea8-b2b2-f4a879cc3275.jpg\"\u003e\u003c\/figure\u003e\u003cp\u003eAll the eight gear examples included in this model, excluding two and three threaded worm, can fit in a single case.\u003cbr\u003eNote that the crown gear and the bevel gear, intermittent gear and spiral gear are facing to each other to save the space.\u003c\/p\u003e\u003cfigure class=\"image\"\u003e\u003cimg src=\"https:\/\/makerworld.bblmw.com\/makerworld\/model\/DSM00000001983808\/design\/3facbd1d-e216-47a6-9f5b-7cfa4cfeb11a.webp\"\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.\u003c\/li\u003e\n\u003cli\u003ePrinting orientations:\u003cul\u003e\n\u003cli\u003eThe \u003cstrong\u003elong shafts\u003c\/strong\u003e of worm and pinion for crown gear should be printed in a \u003cstrong\u003estanding position\u003c\/strong\u003e. Add \u003cstrong\u003ebrims\u003c\/strong\u003e to them for safer printing.\u003c\/li\u003e\n\u003cli\u003ePlace the \u003cstrong\u003eworm\u003c\/strong\u003e so as the flat cross section along the axis \u003cstrong\u003efacing down\u003c\/strong\u003e.\u003cbr\u003e\u003cimg class=\"image_resized\" style=\"width: 36.98%\" src=\"https:\/\/makerworld.bblmw.com\/makerworld\/model\/DSM00000001983808\/design\/3c8e7441-92ab-4e82-b21b-992215d8be6d.png\"\u003e\n\u003c\/li\u003e\n\u003cli\u003eThe \u003cstrong\u003eshort shaft for bevel bear\u003c\/strong\u003e should be printed in a \u003cstrong\u003estanding position\u003c\/strong\u003e, too.\u003cbr\u003e\u003cimg class=\"image_resized\" style=\"width: 50%\" src=\"https:\/\/makerworld.bblmw.com\/makerworld\/model\/DSM00000001983808\/design\/cafbf6a9-30e2-481c-bd92-0fcae141e17c.png\"\u003e\n\u003c\/li\u003e\n\u003cli\u003eArm of the base of the \u003cstrong\u003eSpiral gear pinion\u003c\/strong\u003e should be printed in a position where \u003cstrong\u003ethe axis is pointing up\u003c\/strong\u003e.\u003cbr\u003e\u003cimg class=\"image_resized\" style=\"width: 40.52%\" src=\"https:\/\/makerworld.bblmw.com\/makerworld\/model\/DSM00000001983808\/design\/b604c6c5-c55f-49df-b7de-7c6444f8fde0.png\"\u003e\u003cbr\u003e \u003c\/li\u003e\n\u003c\/ul\u003e\n\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\/DSM00000001983808\/design\/a7d4139c-7b0f-497f-968e-fee65690b52e.webp\"\u003e\u003cimg class=\"image_resized\" style=\"width: 31.94%\" src=\"https:\/\/makerworld.bblmw.com\/makerworld\/model\/DSM00000001983808\/design\/a525e985-6d6f-4941-ac94-fb8791eb24ff.webp\"\u003e\u003cimg class=\"image_resized\" style=\"width: 31.92%\" src=\"https:\/\/makerworld.bblmw.com\/makerworld\/model\/DSM00000001983808\/design\/71b3f9e3-c669-4173-ab6d-060e994e1fe4.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\/DSM00000001983808\/design\/7b4da8d9-1d74-4195-8fee-bcfbce175363.webp\"\u003e\u003c\/figure\u003e\u003cp\u003eWithout those issues, the gears should rotate very smoothly with minimal friction.\u003c\/p\u003e\u003ch2\u003eAssembly\u003c\/h2\u003e\u003cp\u003eNo glue is needed except for the worm.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eWorm: If you feel the shaft of the worm is too loose, glue them by using some super glue.\u003c\/li\u003e\n\u003cli\u003eRack \u0026amp; pinion: Slide in the rack first, before putting the pinion.\u003c\/li\u003e\n\u003cli\u003eInternal: Insert the internal gear first, before the other small gears.\u003c\/li\u003e\n\u003cli\u003eBevel: Insert the shaft for the smaller gear at last.\u003c\/li\u003e\n\u003cli\u003eCrown: The thinner pinion can move along the axis. Be surprised to see that the pinion perfectly fits to the crown gear regardless of the position along the axis.\u003c\/li\u003e\n\u003cli\u003eSpiral: The teeth of the pinion for the spiral gear are bent to have better fit to the spiral gear. Be careful to assemble it in the right direction.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cfigure class=\"image image_resized\" style=\"width: 75%\"\u003e\u003cimg src=\"https:\/\/makerworld.bblmw.com\/makerworld\/model\/DSM00000001983808\/design\/28ab3965-e515-4e2e-a146-6614ddf4ecf0.png\"\u003e\u003c\/figure\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\/DSM00000001983808\/design\/2025-11-13_a0fbbb25e21458.png\"\u003e\u003c\/figure\u003e\u003ch2\u003eUpdates\u003c\/h2\u003e\u003cul\u003e\u003cli\u003e\n\u003cstrong\u003e2025-11-13\u003c\/strong\u003e\u003cul\u003e\u003cli\u003eAdded the STL file for the spiral gear that I forgot to upload earlier.\u003c\/li\u003e\u003c\/ul\u003e\n\u003c\/li\u003e\u003c\/ul\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":67375191294256,"sku":null,"price":36.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0987\/0809\/5280\/files\/0_58ed5483-c29b-498f-baaf-b3b30b57a0fe.png?v=1784229115","url":"https:\/\/mymadmanlab.com\/products\/educational-gear-examples-2","provider":"Mymadmanlab.com","version":"1.0","type":"link"}