{"product_id":"mod-1-steel-spur-gear-12-teeth-bore-4-5-6-7mm-motor-transmission-pinion-gears","title":"Mod 1 Steel Spur Gear 12 Teeth Bore 4\/5\/6\/7mm Motor Transmission Pinion Gears","description":"\u003cdiv class=\"hdiy-desc\"\u003e\n\n  \u003cdiv class=\"hdiy-overview\"\u003e\n    \u003ch2\u003eMod 1 Steel Spur Gear 12T — Reliable Pinion Gear for Motor Transmission Builds\u003c\/h2\u003e\n    \u003cp\u003eWhen a slipping or undersized pinion gear stalls your project, every minute of downtime costs you. Whether you're a robotics builder, RC hobbyist, or automation engineer, finding a dimensionally accurate Mod 1 spur gear with the right bore size shouldn't be a bottleneck. These Mod 1 Steel Spur Gears with 12 teeth are engineered for builders who need consistent mesh quality and dependable torque transfer across a range of shaft diameters.\u003c\/p\u003e\n    \u003cp\u003eEach gear is machined from carbon steel, offering a balance of strength and machinability suited to motor-driven transmission systems. The module (Mod 1) defines the tooth pitch, ensuring direct compatibility with any other Mod 1 gear in your drivetrain. Available bore sizes range from 4mm to 7mm (~0.157\" to ~0.276\"), covering the most common motor shaft diameters used in small-to-medium power transmission applications. Tooth count is fixed at 12T, with an outer diameter typically in the 14mm range (~0.55\").\u003c\/p\u003e\n    \u003cp\u003eThese pinion gears are well-suited for DC motor gearbox assemblies, 3D printer extruder drives, and light CNC axis drives where a compact, low-tooth-count spur gear is required for speed reduction or torque multiplication. Long-tail use cases include \"Mod 1 12 tooth pinion gear for NEMA 17 motor\", \"steel spur gear bore 5mm for robot drivetrain\", and \"replacement transmission gear for RC crawler gearbox\".\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 all Mod 1 (Module 1) spur, helical, and rack gears. Verify your motor shaft diameter matches the selected bore size before ordering.\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"hdiy-features\"\u003e\n    \u003ch2\u003e✅ Key Features of These Mod 1 Steel Spur Pinion Gears\u003c\/h2\u003e\n    \u003cdiv class=\"hdiy-list\"\u003e\n      \u003cdiv\u003e\n        \u003cspan class=\"hdiy-icon\"\u003e🔩\u003c\/span\u003e\n        \u003cstrong\u003eCarbon Steel Construction\u003c\/strong\u003e\n        \u003cp\u003eMachined from carbon steel for reliable strength in motor transmission and drivetrain applications without excessive weight.\u003c\/p\u003e\n      \u003c\/div\u003e\n      \u003cdiv\u003e\n        \u003cspan class=\"hdiy-icon\"\u003e📐\u003c\/span\u003e\n        \u003cstrong\u003eMod 1 Standard Tooth Profile\u003c\/strong\u003e\n        \u003cp\u003eModule 1 tooth geometry ensures direct mesh compatibility with any Mod 1 gear, rack, or pinion in your system — no custom adaptation needed.\u003c\/p\u003e\n      \u003c\/div\u003e\n      \u003cdiv\u003e\n        \u003cspan class=\"hdiy-icon\"\u003e🎯\u003c\/span\u003e\n        \u003cstrong\u003eMultiple Bore Sizes Available\u003c\/strong\u003e\n        \u003cp\u003eChoose from 4mm, 5mm, 6mm, 6.35mm (1\/4\"), or 7mm bore to match your motor shaft precisely. Each variant is machined to tolerance for a secure fit.\u003c\/p\u003e\n      \u003c\/div\u003e\n      \u003cdiv\u003e\n        \u003cspan class=\"hdiy-icon\"\u003e⚡\u003c\/span\u003e\n        \u003cstrong\u003e12-Tooth Pinion for Speed Ratio Flexibility\u003c\/strong\u003e\n        \u003cp\u003eA 12T pinion paired with a larger driven gear delivers effective speed reduction and torque increase — ideal for compact gearbox stages.\u003c\/p\u003e\n      \u003c\/div\u003e\n      \u003cdiv\u003e\n        \u003cspan class=\"hdiy-icon\"\u003e🔄\u003c\/span\u003e\n        \u003cstrong\u003eSmooth, Low-Noise Mesh\u003c\/strong\u003e\n        \u003cp\u003eAccurately cut tooth flanks promote consistent contact ratio and reduced backlash, contributing to quieter operation in precision motion systems.\u003c\/p\u003e\n      \u003c\/div\u003e\n      \u003cdiv\u003e\n        \u003cspan class=\"hdiy-icon\"\u003e🛠️\u003c\/span\u003e\n        \u003cstrong\u003eDrop-In Replacement Compatibility\u003c\/strong\u003e\n        \u003cp\u003eDimensionally consistent with standard Mod 1 pinion gears, making these a straightforward replacement for worn or damaged gears in existing assemblies.\u003c\/p\u003e\n      \u003c\/div\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"hdiy-table-wrap\"\u003e\n    \u003ch2\u003e📐 Technical Specifications — Mod 1 Spur Pinion Gear\u003c\/h2\u003e\n    \u003ctable\u003e\n      \u003ctbody\u003e\n        \u003ctr\u003e\n\u003cth\u003eModule\u003c\/th\u003e\n\u003ctd\u003eMod 1 (Module 1)\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eNumber of Teeth\u003c\/th\u003e\n\u003ctd\u003e12T\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eBore Size Options\u003c\/th\u003e\n\u003ctd\u003e4mm \/ 5mm \/ 6mm \/ 6.35mm \/ 7mm\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eOuter Diameter\u003c\/th\u003e\n\u003ctd\u003eSee variant options\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\u003eMaterial\u003c\/th\u003e\n\u003ctd\u003eCarbon Steel\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eFinish\u003c\/th\u003e\n\u003ctd\u003eSee variant options\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\u003eGear Type\u003c\/th\u003e\n\u003ctd\u003eSpur Gear (Pinion)\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eHub \/ Set Screw\u003c\/th\u003e\n\u003ctd\u003eSee variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eQuantity per Pack\u003c\/th\u003e\n\u003ctd\u003e1 piece\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 shaft diameter with a caliper. Common sizes are 4mm, 5mm, 6mm, 6.35mm (standard 1\/4\" imperial shaft), and 7mm. Select the bore that matches your shaft exactly — a loose fit will cause slippage under load, while an oversized shaft will not insert. If your shaft is between sizes, a 6.35mm bore with a set screw can sometimes accommodate a 6mm shaft with shimming.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eWhat does \"Mod 1\" mean and will this gear mesh with my existing gears?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003e\"Mod 1\" (Module 1) is a standardized metric tooth size designation. It means the pitch diameter equals the number of teeth in millimeters (so a 12T Mod 1 gear has a 12mm pitch diameter). Any two Mod 1 gears with the same pressure angle (20° is standard) will mesh correctly regardless of tooth count. Do not mix modules — a Mod 1 gear will not mesh properly with a Mod 0.8 or Mod 1.5 gear.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eIs this gear strong enough for my application?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eThese gears are machined from carbon steel, which provides good tensile strength for light-to-medium duty motor transmission tasks such as robotics, 3D printer drives, and small CNC systems. For heavy industrial loads or continuous high-torque applications, consult the torque rating of your specific motor and verify the gear's face width and material grade are appropriate. Contact us to confirm suitability for demanding use cases.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eAre these gears corrosion resistant?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eCarbon steel has moderate corrosion resistance. For indoor, dry environments these gears perform well without additional treatment. If your application involves moisture, humidity, or occasional exposure to liquids, applying a light machine oil or grease to the gear teeth will extend service life. For outdoor or wet environments, consider stainless steel alternatives.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eCan I use this gear with a rack (linear gear)?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eYes. A Mod 1 spur gear meshes directly with a Mod 1 gear rack, making this 12T pinion suitable for linear motion systems such as small CNC gantries, camera sliders, or drawer actuators. Ensure the rack's pressure angle matches (20° standard) and that the gear is mounted at the correct center distance from the rack surface.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eHow do I secure the gear to the motor shaft?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eSecuring method depends on the variant. Many pinion gears of this type include a set screw (grub screw) on the hub that tightens against the shaft — check the product images for your selected variant. For shafts with a flat (D-shaft), align the set screw to the flat for maximum grip. If no set screw is present, a press fit or adhesive retaining compound (e.g., Loctite 638) can be used for permanent installation.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eWhat gear ratio can I achieve with this 12T pinion?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eGear ratio = driven gear teeth ÷ driving gear teeth. With this 12T pinion driving a 36T gear, you get a 3:1 reduction (output speed is 1\/3 of input, torque is 3× input). Pair it with a 24T gear for 2:1, or a 60T gear for 5:1. The 12T count makes it well-suited as the first stage in a multi-stage gearbox where significant speed reduction is needed.\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 modulus-tooth and bore size 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 shaft diameter with a caliper. Common sizes are 4mm, 5mm, 6mm, 6.35mm (standard 1\/4\\\" imperial shaft), and 7mm. Select the bore that matches your shaft exactly. If your shaft is between sizes, a 6.35mm bore with a set screw can sometimes accommodate a 6mm shaft with shimming.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"What does Mod 1 mean and will this gear mesh with my existing gears?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Mod 1 (Module 1) is a standardized metric tooth size. A 12T Mod 1 gear has a 12mm pitch diameter. Any two Mod 1 gears with the same 20° pressure angle will mesh correctly. Do not mix modules — Mod 1 will not mesh with Mod 0.8 or Mod 1.5.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Is this gear strong enough for my application?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"These carbon steel gears are suitable for light-to-medium duty motor transmission tasks such as robotics, 3D printer drives, and small CNC systems. Contact us to confirm suitability for heavy-duty or continuous high-torque applications.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Are these gears corrosion resistant?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Carbon steel has moderate corrosion resistance. For dry indoor environments these gears perform well. Apply light machine oil or grease for humid or wet conditions. For outdoor use, consider stainless steel alternatives.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Can I use this gear with a rack (linear gear)?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Yes. A Mod 1 spur gear meshes directly with a Mod 1 gear rack, making this 12T pinion suitable for linear motion systems such as small CNC gantries, camera sliders, or drawer actuators.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"How do I secure the gear to the motor shaft?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Many pinion gears of this type include a set screw on the hub. For D-shafts, align the set screw to the flat for maximum grip. A press fit or retaining compound such as Loctite 638 can be used for permanent installation.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"What gear ratio can I achieve with this 12T pinion?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Gear ratio = driven gear teeth ÷ 12. A 36T driven gear gives 3:1 reduction, 24T gives 2:1, and 60T gives 5:1. The 12T count is ideal as the first stage in a multi-stage gearbox.\"\n      }\n    }\n  ]\n}\n\u003c\/script\u003e","brand":"HomeDIYer","offers":[{"title":"1M-12T \/ 4mm","offer_id":52442119012626,"sku":"GLFBCQFGLBZSJ057376x1","price":9.15,"currency_code":"USD","in_stock":true},{"title":"1M-12T \/ 5mm","offer_id":52442119045394,"sku":"GLFBCQFGLBZSJ057377x1","price":9.15,"currency_code":"USD","in_stock":true},{"title":"1M-12T \/ 6mm","offer_id":52442119078162,"sku":"GLFBCQFGLBZSJ057378x1","price":9.15,"currency_code":"USD","in_stock":true},{"title":"1M-12T \/ 6.35mm","offer_id":52442119110930,"sku":"GLFBCQFGLBZSJ057379x1","price":9.49,"currency_code":"USD","in_stock":true},{"title":"1M-12T \/ 7mm","offer_id":52442119143698,"sku":"GLFBCQFGLBZSJ057380x1","price":9.49,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0884\/8936\/1682\/files\/Main-01_f147418a-7880-4057-8962-b78dc4fdd22c.jpg?v=1783408273","url":"https:\/\/homediyer.com\/products\/mod-1-steel-spur-gear-12-teeth-bore-4-5-6-7mm-motor-transmission-pinion-gears","provider":"HomeDIYer","version":"1.0","type":"link"}