{"product_id":"0-5-mod-20-teeth-spur-gear-4-5-6-6-35mm-bore-black-oxide-steel-with-set-screws","title":"0.5 Mod 20 Teeth Spur Gear 4\/5\/6\/6.35mm Bore Black Oxide Steel with Set Screws","description":"\u003cdiv class=\"hdiy-desc\"\u003e\n\n  \u003cdiv class=\"hdiy-overview\"\u003e\n    \u003ch2\u003e0.5 Mod 20-Tooth Spur Gear — Black Oxide Steel for Precision Drive Systems\u003c\/h2\u003e\n    \u003cp\u003eWhen your motion-control build demands tight mesh tolerances and reliable torque transfer, a poorly fitted gear can derail the entire mechanism. Engineers, robotics hobbyists, and CNC makers who need a compact 0.5 Mod 20-tooth spur gear with a secure shaft fit will find this black oxide steel gear a dependable solution across a wide range of shaft diameters.\u003c\/p\u003e\n    \u003cp\u003eEach gear is machined from carbon steel and finished with a black oxide coating for corrosion resistance. The module is 0.5 with 20 teeth, giving an outer diameter of approximately 11 mm (0.43 in). Bore options span 4 mm, 5 mm, 6 mm, and 6.35 mm (1\/4 in), covering the most common motor and shaft standards. A set screw is included on each gear for positive shaft retention without adhesives.\u003c\/p\u003e\n    \u003cp\u003eTypical use cases include small robotic arm joints requiring a 0.5 mod spur gear with set screw, compact CNC axis drives using a 20-tooth steel gear with 6 mm bore, and DIY clock or automaton mechanisms where a miniature black oxide spur gear keeps aesthetics clean while maintaining durability.\u003c\/p\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"hdiy-compat\"\u003e\n    \u003cspan class=\"hdiy-compat-icon\"\u003e⚙️\u003c\/span\u003e\n    \u003cstrong\u003eCompatibility:\u003c\/strong\u003e Meshes with any 0.5 module (Mod 0.5) spur, rack, or pinion gear. Bore sizes 4 \/ 5 \/ 6 \/ 6.35 mm fit standard motor shafts and hobby servo output shafts. Verify shaft diameter and keyway requirements before ordering.\n  \u003c\/div\u003e\n\n  \u003ch2\u003e✅ Key Features of These 0.5 Mod 20-Tooth Black Oxide Steel Spur Gears\u003c\/h2\u003e\n  \u003cdiv class=\"hdiy-features\"\u003e\n\n    \u003cdiv\u003e\n      \u003cdiv class=\"hdiy-icon\"\u003e🔩\u003c\/div\u003e\n      \u003cstrong\u003eSet Screw Retention\u003c\/strong\u003e\n      \u003cp\u003eEach gear includes a radial set screw for positive shaft locking — no adhesive or press-fit required, making disassembly and repositioning straightforward.\u003c\/p\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv\u003e\n      \u003cdiv class=\"hdiy-icon\"\u003e🛡️\u003c\/div\u003e\n      \u003cstrong\u003eBlack Oxide Finish\u003c\/strong\u003e\n      \u003cp\u003eThe black oxide surface treatment provides mild corrosion resistance and reduces light reflection — suitable for indoor mechanical assemblies and light-duty outdoor enclosures.\u003c\/p\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv\u003e\n      \u003cdiv class=\"hdiy-icon\"\u003e📐\u003c\/div\u003e\n      \u003cstrong\u003ePrecision 0.5 Module Profile\u003c\/strong\u003e\n      \u003cp\u003eMachined to 0.5 module standard, these gears mesh accurately with any Mod 0.5 counterpart — rack, pinion, or mating spur — for smooth, low-backlash power transmission.\u003c\/p\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv\u003e\n      \u003cdiv class=\"hdiy-icon\"\u003e🎯\u003c\/div\u003e\n      \u003cstrong\u003eFour Bore Options\u003c\/strong\u003e\n      \u003cp\u003eAvailable in 4 mm, 5 mm, 6 mm, and 6.35 mm (1\/4 in) bore diameters to match the most common motor shaft and hobby shaft standards without custom machining.\u003c\/p\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv\u003e\n      \u003cdiv class=\"hdiy-icon\"\u003e⚖️\u003c\/div\u003e\n      \u003cstrong\u003eCarbon Steel Construction\u003c\/strong\u003e\n      \u003cp\u003eManufactured from carbon steel for a balance of machinability, tensile strength, and wear resistance — appropriate for moderate-load, moderate-speed drive applications.\u003c\/p\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv\u003e\n      \u003cdiv class=\"hdiy-icon\"\u003e📦\u003c\/div\u003e\n      \u003cstrong\u003eFlexible Pack Quantities\u003c\/strong\u003e\n      \u003cp\u003eOrder as 1, 3, 5, or 10 pieces per variant to match your project scale — from single-unit prototyping to small-batch production runs.\u003c\/p\u003e\n    \u003c\/div\u003e\n\n  \u003c\/div\u003e\n\n  \u003ch2\u003e📐 Technical Specifications — 0.5 Mod Spur Gear\u003c\/h2\u003e\n  \u003cdiv class=\"hdiy-table-wrap\"\u003e\n    \u003ctable\u003e\n      \u003ctbody\u003e\n        \u003ctr\u003e\n\u003cth\u003eModule (Mod)\u003c\/th\u003e\n\u003ctd\u003e0.5\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eNumber of Teeth\u003c\/th\u003e\n\u003ctd\u003e20\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eOuter Diameter (OD)\u003c\/th\u003e\n\u003ctd\u003eApprox. 11 mm (0.43 in)\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003ePitch Diameter\u003c\/th\u003e\n\u003ctd\u003e10 mm (0.39 in)\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eBore Diameter\u003c\/th\u003e\n\u003ctd\u003e4 mm \/ 5 mm \/ 6 mm \/ 6.35 mm (1\/4 in) — See variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eHub \/ Face Width\u003c\/th\u003e\n\u003ctd\u003eSee variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eMaterial\u003c\/th\u003e\n\u003ctd\u003eCarbon Steel\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eSurface Finish\u003c\/th\u003e\n\u003ctd\u003eBlack Oxide\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eShaft Retention\u003c\/th\u003e\n\u003ctd\u003eSet Screw (included)\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003ePressure Angle\u003c\/th\u003e\n\u003ctd\u003e20°\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003ePack Quantity\u003c\/th\u003e\n\u003ctd\u003e1 \/ 3 \/ 5 \/ 10 pcs — See variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003c\/tbody\u003e\n    \u003c\/table\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"hdiy-faq\"\u003e\n    \u003ch2\u003e❓ Frequently Asked Questions\u003c\/h2\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eHow do I choose the right bore size for my motor shaft?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eMeasure your motor or drive shaft diameter with a caliper. Select the bore that matches: 4 mm for small stepper and hobby motors, 5 mm for common NEMA 17 stepper shafts, 6 mm for many DC gear motors, and 6.35 mm (1\/4 in) for standard US hobby and servo shafts. The set screw accommodates minor shaft tolerance variation but is not a substitute for a correct bore match.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eWill this gear mesh with my existing 0.5 module rack or pinion?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eYes. Any gear, rack, or pinion manufactured to the 0.5 module (Mod 0.5) standard will mesh correctly with this gear. Confirm the module and pressure angle (20°) of your mating component before assembly.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eHow strong is the black oxide coating against rust?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eBlack oxide provides mild corrosion resistance suitable for dry or lightly humid indoor environments. For outdoor or high-moisture applications, apply a light machine oil or grease to the gear surface periodically. Black oxide is not equivalent to zinc plating or stainless steel in corrosion protection.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eWhat torque and speed range is this gear rated for?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eExact load ratings depend on application conditions (lubrication, duty cycle, mating gear material). As a conservative guideline for carbon steel Mod 0.5 gears, these are suited for low-to-moderate torque applications typical of robotics, small CNC axes, and instrumentation drives. Contact us to confirm suitability for high-cycle or high-load scenarios.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eDoes the set screw require a specific tool or thread size?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eThe set screw is typically driven with a hex (Allen) key. The exact set screw thread size varies by bore variant — contact us to confirm the wrench size for your specific bore option before assembly.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eCan I use these gears without lubrication?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eThese gears can operate dry at low speeds and light loads, but applying a thin film of gear grease or machine oil at the mesh contact point will significantly extend service life and reduce noise, especially in continuous-duty or higher-speed applications.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eWhy should I order multiple pieces instead of just one?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eMulti-piece packs (3, 5, or 10 pcs) are cost-effective for builds requiring matched gear pairs, redundancy spares, or small-batch production. The per-unit price decreases with larger quantities, making them practical for prototyping iterations where gears may be replaced or repositioned.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"hdiy-cta\"\u003e\n    🛒 Select your Gear Size and Amount above, then add to cart.\n  \u003c\/div\u003e\n\n\u003c\/div\u003e\n\n\u003cscript type=\"application\/ld+json\"\u003e\n{\n  \"@context\": \"https:\/\/schema.org\",\n  \"@type\": \"FAQPage\",\n  \"mainEntity\": [\n    {\n      \"@type\": \"Question\",\n      \"name\": \"How do I choose the right bore size for my motor shaft?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Measure your motor or drive shaft diameter with a caliper. Select the bore that matches: 4 mm for small stepper and hobby motors, 5 mm for common NEMA 17 stepper shafts, 6 mm for many DC gear motors, and 6.35 mm (1\/4 in) for standard US hobby and servo shafts.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Will this gear mesh with my existing 0.5 module rack or pinion?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Yes. Any gear, rack, or pinion manufactured to the 0.5 module (Mod 0.5) standard will mesh correctly with this gear. Confirm the module and pressure angle (20°) of your mating component before assembly.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"How strong is the black oxide coating against rust?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Black oxide provides mild corrosion resistance suitable for dry or lightly humid indoor environments. For outdoor or high-moisture applications, apply a light machine oil or grease to the gear surface periodically.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"What torque and speed range is this gear rated for?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"These are suited for low-to-moderate torque applications typical of robotics, small CNC axes, and instrumentation drives. Contact us to confirm suitability for high-cycle or high-load scenarios.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Does the set screw require a specific tool or thread size?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"The set screw is typically driven with a hex (Allen) key. Contact us to confirm the wrench size for your specific bore option before assembly.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Can I use these gears without lubrication?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"These gears can operate dry at low speeds and light loads, but applying a thin film of gear grease or machine oil at the mesh contact point will significantly extend service life and reduce noise.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Why should I order multiple pieces instead of just one?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Multi-piece packs (3, 5, or 10 pcs) are cost-effective for builds requiring matched gear pairs, redundancy spares, or small-batch production. The per-unit price decreases with larger quantities.\"\n      }\n    }\n  ]\n}\n\u003c\/script\u003e","brand":"HomeDIYer","offers":[{"title":"0.5Mod 20T Bore 5mm \/ 1pcs","offer_id":52441931710738,"sku":"GLFBNHHGLBZSJ057278x1","price":6.38,"currency_code":"USD","in_stock":true},{"title":"0.5Mod 20T Bore 6mm \/ 1pcs","offer_id":52441931743506,"sku":"GLFBNHHGLBZSJ057279x1","price":6.38,"currency_code":"USD","in_stock":true},{"title":"0.5Mod 20T Bore 6.35mm \/ 1pcs","offer_id":52441931776274,"sku":"GLFBNHHGLBZSJ057280x1","price":6.38,"currency_code":"USD","in_stock":true},{"title":"0.5Mod 20T Bore 4mm \/ 1pcs","offer_id":52441931809042,"sku":"GLFBNHHGLCDPJ00030x1","price":6.38,"currency_code":"USD","in_stock":true},{"title":"0.5Mod 20T Bore 5mm \/ 3pcs","offer_id":52441931841810,"sku":"GLFBNHHGLBZSJ057278x3","price":15.3,"currency_code":"USD","in_stock":true},{"title":"0.5Mod 20T Bore 6mm \/ 3pcs","offer_id":52441931874578,"sku":"GLFBNHHGLBZSJ057279x3","price":15.3,"currency_code":"USD","in_stock":true},{"title":"0.5Mod 20T Bore 6.35mm \/ 3pcs","offer_id":52441931907346,"sku":"GLFBNHHGLBZSJ057280x3","price":15.3,"currency_code":"USD","in_stock":true},{"title":"0.5Mod 20T Bore 4mm \/ 3pcs","offer_id":52441931940114,"sku":"GLFBNHHGLCDPJ00030x3","price":15.3,"currency_code":"USD","in_stock":true},{"title":"0.5Mod 20T Bore 5mm \/ 5pcs","offer_id":52441931972882,"sku":"GLFBNHHGLBZSJ057278x5","price":24.74,"currency_code":"USD","in_stock":true},{"title":"0.5Mod 20T Bore 6mm \/ 5pcs","offer_id":52441932005650,"sku":"GLFBNHHGLBZSJ057279x5","price":24.74,"currency_code":"USD","in_stock":true},{"title":"0.5Mod 20T Bore 6.35mm \/ 5pcs","offer_id":52441932038418,"sku":"GLFBNHHGLBZSJ057280x5","price":24.74,"currency_code":"USD","in_stock":true},{"title":"0.5Mod 20T Bore 4mm \/ 5pcs","offer_id":52441932071186,"sku":"GLFBNHHGLCDPJ00030x5","price":24.74,"currency_code":"USD","in_stock":true},{"title":"0.5Mod 20T Bore 5mm \/ 10pcs","offer_id":52441932103954,"sku":"GLFBNHHGLBZSJ057278x10","price":48.27,"currency_code":"USD","in_stock":true},{"title":"0.5Mod 20T Bore 6mm \/ 10pcs","offer_id":52441932136722,"sku":"GLFBNHHGLBZSJ057279x10","price":48.27,"currency_code":"USD","in_stock":true},{"title":"0.5Mod 20T Bore 6.35mm \/ 10pcs","offer_id":52441932169490,"sku":"GLFBNHHGLBZSJ057280x10","price":48.27,"currency_code":"USD","in_stock":true},{"title":"0.5Mod 20T Bore 4mm \/ 10pcs","offer_id":52441932202258,"sku":"GLFBNHHGLCDPJ00030x10","price":48.27,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0884\/8936\/1682\/files\/Picture4of9_b7f71f2e-2032-4492-9e1d-1fd722db82e6.jpg?v=1783585321","url":"https:\/\/homediyer.com\/products\/0-5-mod-20-teeth-spur-gear-4-5-6-6-35mm-bore-black-oxide-steel-with-set-screws","provider":"HomeDIYer","version":"1.0","type":"link"}