{"product_id":"0-5-mod-brass-spur-gear-38-teeth-bore-4-12mm-motor-gear-transmission-pinion-gear","title":"0.5 Mod Brass Spur Gear 38 Teeth Bore 4~12mm Motor Gear Transmission Pinion Gear","description":"\u003cdiv class=\"hdiy-desc\"\u003e\n\n  \u003cdiv class=\"hdiy-overview\"\u003e\n    \u003ch2\u003e0.5 Mod Brass Spur Gear 38T — Reliable Pinion Gear for Precision Drive Systems\u003c\/h2\u003e\n    \u003cp\u003eWhen a slipping or undersized gear throws off your entire drivetrain, the downstream damage — stripped teeth, misaligned shafts, lost torque — costs far more than the part itself. Hobbyists, robotics builders, and small-machine engineers who need a dimensionally consistent, metal-bodied pinion gear will find this 0.5 module brass spur gear a dependable drop-in solution.\u003c\/p\u003e\n    \u003cp\u003eEach gear is machined from brass, offering a balance of machinability, moderate corrosion resistance, and low-noise meshing. The gear features 38 teeth at 0.5 module (Mod 0.5), with a pitch diameter of 19 mm (approx. 0.748 in). Bore options span 4 mm to 12 mm (approx. 0.157 in to 0.472 in), covering the most common motor shaft diameters used in compact drive applications. Overall gear width is typically 5–8 mm depending on bore variant.\u003c\/p\u003e\n    \u003cp\u003eTypical use cases include RC car transmission pinion replacement, stepper motor output gears in 3D printer extruder assemblies, and compact robotic joint actuators requiring a 0.5 mod 38-tooth spur gear with a defined bore-to-shaft fit.\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 Mod 0.5 spur or helical gear. Verify bore diameter matches your motor or drive shaft before ordering.\n  \u003c\/div\u003e\n\n  \u003ch2\u003e✅ Key Features of These 0.5 Mod Brass 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\u003eBrass Construction\u003c\/strong\u003e\n      \u003cp\u003eMachined from brass for reliable torque transmission, quiet meshing, and resistance to surface oxidation in typical indoor environments.\u003c\/p\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv\u003e\n      \u003cdiv class=\"hdiy-icon\"\u003e📐\u003c\/div\u003e\n      \u003cstrong\u003e38 Teeth, 0.5 Module\u003c\/strong\u003e\n      \u003cp\u003e19 mm pitch diameter with 38 evenly spaced teeth at Mod 0.5 — compatible with the full range of 0.5 module gear systems used in compact drives.\u003c\/p\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv\u003e\n      \u003cdiv class=\"hdiy-icon\"\u003e🎯\u003c\/div\u003e\n      \u003cstrong\u003eMulti-Bore Options (4–12 mm)\u003c\/strong\u003e\n      \u003cp\u003eAvailable in bore diameters of 4, 5, 6, 6.35, 7, 8, 10, and 12 mm to match standard motor shaft sizes 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\u003eDirect Pinion Replacement\u003c\/strong\u003e\n      \u003cp\u003eDesigned as a drop-in pinion gear for RC vehicles, extruder drives, and small automation systems where Mod 0.5 gearing is specified.\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, 2, 5, or 10-piece packs — ideal for prototyping single builds or stocking spares for production runs.\u003c\/p\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv\u003e\n      \u003cdiv class=\"hdiy-icon\"\u003e⚖️\u003c\/div\u003e\n      \u003cstrong\u003eConsistent Dimensional Tolerances\u003c\/strong\u003e\n      \u003cp\u003eEach gear is produced to consistent tooth profile and bore tolerances, reducing backlash variation across multi-gear assemblies.\u003c\/p\u003e\n    \u003c\/div\u003e\n\n  \u003c\/div\u003e\n\n  \u003ch2\u003e📐 Technical Specifications — 0.5 Mod Brass Spur Gear\u003c\/h2\u003e\n  \u003cdiv class=\"hdiy-table-wrap\"\u003e\n    \u003ctable\u003e\n      \u003ctbody\u003e\n        \u003ctr\u003e\n\u003cth\u003eModule\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\u003e38T\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003ePitch Diameter\u003c\/th\u003e\n\u003ctd\u003e19 mm (0.748 in)\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eBore Diameter\u003c\/th\u003e\n\u003ctd\u003e4 \/ 5 \/ 6 \/ 6.35 \/ 7 \/ 8 \/ 10 \/ 12 mm — See variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eMaterial\u003c\/th\u003e\n\u003ctd\u003eBrass\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eGear Type\u003c\/th\u003e\n\u003ctd\u003eSpur Gear (Pinion)\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\u003eFace Width\u003c\/th\u003e\n\u003ctd\u003eSee variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eHub Style\u003c\/th\u003e\n\u003ctd\u003eSee variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eFinish\u003c\/th\u003e\n\u003ctd\u003eNatural brass (uncoated)\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003ePack Quantity\u003c\/th\u003e\n\u003ctd\u003e1 \/ 2 \/ 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 diameter 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 option that matches exactly — for example, a 5 mm shaft requires the Bore 5 mm variant. If your shaft is imperial (e.g., 1\/4 in = 6.35 mm), choose the 6.35 mm bore option. A loose bore fit will cause shaft slippage under load.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eIs this gear strong enough for continuous-duty motor applications?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eBrass spur gears at Mod 0.5 are well-suited for light-to-medium duty applications such as RC drivetrains, 3D printer extruders, and small robotic joints. For high-torque or continuous industrial duty cycles, consider steel gears. Brass offers quieter operation and adequate strength for most hobbyist and maker use cases.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eWill this gear corrode or oxidize over time?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eBrass has inherent corrosion resistance in dry and typical indoor environments. Surface tarnishing (oxidation) may occur over time but does not significantly affect mechanical performance. For outdoor or high-humidity applications, periodic light lubrication is recommended.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eWhat other gears will mesh with this 0.5 Mod 38T spur gear?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eThis gear meshes with any Mod 0.5 spur or helical gear of the same pressure angle (20°). The mating gear tooth count determines the gear ratio. For example, pairing with a 19T pinion gives a 2:1 reduction ratio. Ensure the mating gear's face width and bore alignment are compatible with your assembly.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eHow do I decide between 1 PCS, 2 PCS, 5 PCS, or 10 PCS packs?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eFor single prototype builds or one-off repairs, the 1 PCS option is sufficient. If you are building a multi-gear assembly or want a spare on hand, 2 PCS is practical. The 5 PCS and 10 PCS packs offer a lower per-unit cost and are suited for small production runs, classroom kits, or stocking spare parts for ongoing projects.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eCan I use this gear with a set screw or do I need to press-fit it?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eThe bore is machined for a close sliding or light interference fit on the shaft. Whether you use a set screw, retaining ring, or press-fit depends on your assembly design. The gear does not include a pre-drilled set screw hole unless specified in the variant listing — check the variant details or contact us to confirm before ordering.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eIs the 6.35 mm bore option suitable for 1\/4-inch shafts?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eYes. 6.35 mm is the metric equivalent of 1\/4 inch (0.250 in), making the Bore 6.35 mm variant the correct choice for standard 1\/4-inch motor shafts commonly found in North American hobby motors and small DC gearmotors.\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 bore size and pack quantity 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 diameter for my motor shaft?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Measure your motor or drive shaft diameter with a caliper. Select the bore option that matches exactly — for example, a 5 mm shaft requires the Bore 5 mm variant. If your shaft is imperial (e.g., 1\/4 in = 6.35 mm), choose the 6.35 mm bore option. A loose bore fit will cause shaft slippage under load.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Is this gear strong enough for continuous-duty motor applications?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Brass spur gears at Mod 0.5 are well-suited for light-to-medium duty applications such as RC drivetrains, 3D printer extruders, and small robotic joints. For high-torque or continuous industrial duty cycles, consider steel gears. Brass offers quieter operation and adequate strength for most hobbyist and maker use cases.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Will this gear corrode or oxidize over time?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Brass has inherent corrosion resistance in dry and typical indoor environments. Surface tarnishing may occur over time but does not significantly affect mechanical performance. For outdoor or high-humidity applications, periodic light lubrication is recommended.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"What other gears will mesh with this 0.5 Mod 38T spur gear?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"This gear meshes with any Mod 0.5 spur or helical gear of the same pressure angle (20°). The mating gear tooth count determines the gear ratio. Ensure the mating gear's face width and bore alignment are compatible with your assembly.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"How do I decide between 1 PCS, 2 PCS, 5 PCS, or 10 PCS packs?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"For single prototype builds or one-off repairs, the 1 PCS option is sufficient. The 5 PCS and 10 PCS packs offer a lower per-unit cost and are suited for small production runs, classroom kits, or stocking spare parts for ongoing projects.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Can I use this gear with a set screw or do I need to press-fit it?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"The bore is machined for a close sliding or light interference fit on the shaft. Whether you use a set screw, retaining ring, or press-fit depends on your assembly design. Check the variant details or contact us to confirm before ordering.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Is the 6.35 mm bore option suitable for 1\/4-inch shafts?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Yes. 6.35 mm is the metric equivalent of 1\/4 inch (0.250 in), making the Bore 6.35 mm variant the correct choice for standard 1\/4-inch motor shafts commonly found in North American hobby motors and small DC gearmotors.\"\n      }\n    }\n  ]\n}\n\u003c\/script\u003e","brand":"HomeDIYer","offers":[{"title":"0.5 Mod 38T 【Bore 4mm】 \/ 1 PCS","offer_id":52442801504530,"sku":"AdaahGFCD04433x1","price":9.86,"currency_code":"USD","in_stock":true},{"title":"0.5 Mod 38T 【Bore 5mm】 \/ 1 PCS","offer_id":52442801537298,"sku":"AdaahGFCD04434x1","price":9.86,"currency_code":"USD","in_stock":true},{"title":"0.5 Mod 38T 【Bore 6mm】 \/ 1 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PCS","offer_id":52442802520338,"sku":"AdaahGFCD04440x10","price":64.31,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0884\/8936\/1682\/files\/Picture3of15_7ed92ab0-dc86-4a2d-af0f-ebd9a30bc227.jpg?v=1783596312","url":"https:\/\/homediyer.com\/products\/0-5-mod-brass-spur-gear-38-teeth-bore-4-12mm-motor-gear-transmission-pinion-gear","provider":"HomeDIYer","version":"1.0","type":"link"}