{"product_id":"4-modulus-spur-gear-10t-22t-flat-gear-45-steel-transmission-gears-od-48-96mm","title":"4 Modulus Spur Gear 10T - 22T Flat Gear 45 Steel Transmission Gears OD 48-96mm","description":"\u003cdiv class=\"hdiy-desc\"\u003e\n\n  \u003cdiv class=\"hdiy-overview\"\u003e\n    \u003ch2\u003eModule 4 Spur Gear — Precision 45 Steel Flat Gear for Reliable Power Transmission\u003c\/h2\u003e\n    \u003cp\u003eWhen your drive system demands consistent torque transfer and dimensional accuracy, an undersized or poorly machined gear becomes the weakest link in the chain. Engineers, robotics builders, and machine designers who need a dependable module 4 spur gear with a verified tooth profile will find this flat gear a direct fit for demanding mechanical assemblies.\u003c\/p\u003e\n    \u003cp\u003eEach gear is machined from 45 steel (medium-carbon steel, equivalent to C45 \/ S45C), offering a balanced combination of strength and machinability. The module 4 spur gear range covers 10 teeth to 22 teeth, with outer diameters spanning 48 mm to 96 mm (approximately 1.89 in to 3.78 in). Tooth width (face width) is consistent with standard module 4 geometry; bore diameter varies by tooth count — see variant options for exact bore dimensions.\u003c\/p\u003e\n    \u003cp\u003eTypical applications include CNC router axis drives, robotic arm joint transmissions, conveyor indexing mechanisms, and small-batch automation equipment where a module 4 spur gear with a flat (non-helical) tooth profile is specified. The straight-tooth design simplifies alignment and allows axial assembly without thrust bearing considerations, making it a practical choice for parallel-shaft gear reduction stages and DIY power transmission projects.\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 standard Module 4 (Mod 4) spur gear, rack, or pinion. Verify center distance using the formula: \u003cem\u003eCD = (T₁ + T₂) × m \/ 2\u003c\/em\u003e, where m = 4 mm.\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"hdiy-features\"\u003e\n    \u003ch2\u003e✅ Key Features of These Module 4 Spur Gears\u003c\/h2\u003e\n    \u003cdiv class=\"hdiy-list\"\u003e\n      \u003cdiv\u003e\n        \u003cspan class=\"hdiy-icon\"\u003e🔩\u003c\/span\u003e\n        \u003cstrong\u003e45 Steel Construction\u003c\/strong\u003e — Medium-carbon steel delivers solid tensile strength and wear resistance for sustained mesh loads in industrial and hobbyist drive systems.\n      \u003c\/div\u003e\n      \u003cdiv\u003e\n        \u003cspan class=\"hdiy-icon\"\u003e📐\u003c\/span\u003e\n        \u003cstrong\u003eWide Tooth-Count Selection\u003c\/strong\u003e — 10T through 22T in a single listing; outer diameters from 48 mm (1.89 in) to 96 mm (3.78 in) to match your gear ratio requirements without custom machining.\n      \u003c\/div\u003e\n      \u003cdiv\u003e\n        \u003cspan class=\"hdiy-icon\"\u003e⚡\u003c\/span\u003e\n        \u003cstrong\u003eStandard Module 4 Tooth Profile\u003c\/strong\u003e — 20° pressure angle, straight spur tooth geometry; fully interchangeable with any Mod 4 mating gear or rack on the market.\n      \u003c\/div\u003e\n      \u003cdiv\u003e\n        \u003cspan class=\"hdiy-icon\"\u003e🎯\u003c\/span\u003e\n        \u003cstrong\u003eFlat Gear Design\u003c\/strong\u003e — No helix angle means zero axial thrust force, simplifying shaft and bearing selection in parallel-axis gearbox builds.\n      \u003c\/div\u003e\n      \u003cdiv\u003e\n        \u003cspan class=\"hdiy-icon\"\u003e🔄\u003c\/span\u003e\n        \u003cstrong\u003eMulti-Piece Quantity Options\u003c\/strong\u003e — Available in packs of 1, 2, or 3 per order; ideal for building matched gear pairs or stocking spares for ongoing production runs.\n      \u003c\/div\u003e\n      \u003cdiv\u003e\n        \u003cspan class=\"hdiy-icon\"\u003e🛠️\u003c\/span\u003e\n        \u003cstrong\u003eMachinable Bore\u003c\/strong\u003e — Standard bore can be re-bored or keyway-cut to match your shaft diameter, giving flexibility for custom shaft fits in prototype and small-batch builds.\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 — Module 4 Spur Gear\u003c\/h2\u003e\n    \u003ctable\u003e\n      \u003ctbody\u003e\n        \u003ctr\u003e\n\u003cth\u003eModule (m)\u003c\/th\u003e\n\u003ctd\u003e4\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\u003eTooth Type\u003c\/th\u003e\n\u003ctd\u003eStraight spur (flat gear)\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eTeeth Range\u003c\/th\u003e\n\u003ctd\u003e10T – 22T\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eOuter Diameter (OD) Range\u003c\/th\u003e\n\u003ctd\u003e48 mm – 96 mm (1.89 in – 3.78 in)\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eMaterial\u003c\/th\u003e\n\u003ctd\u003e45 Steel (medium-carbon, C45 \/ S45C equivalent)\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eSurface Finish\u003c\/th\u003e\n\u003ctd\u003eSee variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eBore Diameter\u003c\/th\u003e\n\u003ctd\u003eSee variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eFace Width (Tooth Width)\u003c\/th\u003e\n\u003ctd\u003eSee variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eHub Diameter\u003c\/th\u003e\n\u003ctd\u003eSee variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eKeyway\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 \/ 2 \/ 3 pcs (select above)\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 tooth count for my application?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eSelect tooth count based on your required gear ratio and available center distance. For a 2:1 reduction, pair a 10T pinion with a 20T gear. Center distance (CD) = (T₁ + T₂) × 4 \/ 2. Smaller tooth counts produce more compact assemblies; larger tooth counts distribute load across more teeth for smoother, quieter operation.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eWhat is the load capacity of a Module 4 spur gear in 45 steel?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003e45 steel has a typical tensile strength of 600–800 MPa and yield strength of approximately 355 MPa in the normalized condition. Actual gear load capacity depends on tooth count, face width, operating speed, and lubrication. For high-cycle or shock-load applications, consider surface hardening (induction hardening or case hardening) after machining the bore to your shaft size.\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\u003e45 steel is a carbon steel and will oxidize if exposed to moisture without protection. For corrosion resistance, apply a light machine oil, grease, or a surface coating such as black oxide or zinc plating after installation. For environments with continuous moisture exposure, consider stainless steel or plastic gears instead.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eWill this gear mesh with my existing Module 4 rack or pinion?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eYes. Any gear or rack manufactured to the Module 4 standard with a 20° pressure angle will mesh correctly with these gears. Confirm the module and pressure angle of your existing components before ordering. Module 4 is not interchangeable with DP (diametral pitch) gears — if your existing system uses DP gearing, you will need a conversion.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eCan I re-bore or add a keyway to the standard bore?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eYes. 45 steel machines well on a lathe or mill. The bore can be enlarged and a keyway or set-screw flat can be added by a machine shop to match your shaft diameter. Ensure sufficient hub wall thickness remains after boring — contact us to confirm hub dimensions for your selected tooth count before machining.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eWhat quantity options are available, and when should I order multiples?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eEach variant is available in packs of 1, 2, or 3 pieces. Order 2 when building a matched gear pair (e.g., input and output gears of the same size for a parallel shaft). Order 3 when you need one installed gear plus spares for a production run or field maintenance kit. Buying in a pack is more economical than separate single-piece orders.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eWhat is the difference between a flat spur gear and a helical gear, and which should I choose?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eA flat (straight-tooth) spur gear has teeth parallel to the gear axis, producing no axial thrust force. This simplifies bearing selection and assembly. Helical gears have angled teeth that engage more gradually, resulting in quieter operation and higher load capacity, but they generate axial thrust that must be managed with thrust bearings. For most DIY, robotics, and light industrial applications, a straight spur gear is the simpler and more cost-effective choice.\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 Teeth-OD size and 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 tooth count for my application?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Select tooth count based on your required gear ratio and available center distance. For a 2:1 reduction, pair a 10T pinion with a 20T gear. Center distance (CD) = (T1 + T2) x 4 \/ 2. Smaller tooth counts produce more compact assemblies; larger tooth counts distribute load across more teeth for smoother, quieter operation.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"What is the load capacity of a Module 4 spur gear in 45 steel?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"45 steel has a typical tensile strength of 600-800 MPa and yield strength of approximately 355 MPa in the normalized condition. Actual gear load capacity depends on tooth count, face width, operating speed, and lubrication.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Are these gears corrosion-resistant?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"45 steel is a carbon steel and will oxidize if exposed to moisture without protection. Apply a light machine oil, grease, or surface coating such as black oxide or zinc plating after installation.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Will this gear mesh with my existing Module 4 rack or pinion?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Yes. Any gear or rack manufactured to the Module 4 standard with a 20 degree pressure angle will mesh correctly with these gears. Module 4 is not interchangeable with DP (diametral pitch) gears.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Can I re-bore or add a keyway to the standard bore?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Yes. 45 steel machines well on a lathe or mill. The bore can be enlarged and a keyway or set-screw flat can be added by a machine shop to match your shaft diameter.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"What quantity options are available, and when should I order multiples?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Each variant is available in packs of 1, 2, or 3 pieces. Order 2 when building a matched gear pair. Order 3 when you need one installed gear plus spares for a production run or field maintenance kit.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"What is the difference between a flat spur gear and a helical gear, and which should I choose?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"A flat (straight-tooth) spur gear has teeth parallel to the gear axis, producing no axial thrust force. Helical gears have angled teeth that engage more gradually, resulting in quieter operation and higher load capacity, but they generate axial thrust. For most DIY, robotics, and light industrial applications, a straight spur gear is the simpler and more cost-effective choice.\"\n      }\n    }\n  ]\n}\n\u003c\/script\u003e","brand":"HomeDIYer","offers":[{"title":"4Modul \/ 10T - OD 48mm \/ 1","offer_id":52442988478738,"sku":"PHGLFBLTYGLBZSJ058241x1","price":24.82,"currency_code":"USD","in_stock":true},{"title":"4Modul \/ 10T - OD 48mm \/ 2","offer_id":52442988511506,"sku":"PHGLFBLTYGLBZSJ058241x2","price":48.52,"currency_code":"USD","in_stock":true},{"title":"4Modul \/ 10T - OD 48mm \/ 3","offer_id":52442988544274,"sku":"PHGLFBLTYGLBZSJ058241x3","price":72.23,"currency_code":"USD","in_stock":true},{"title":"4Modul \/ 11T - OD 52mm \/ 1","offer_id":52442988577042,"sku":"PHGLFBLTYGLBZSJ058242x1","price":26.45,"currency_code":"USD","in_stock":true},{"title":"4Modul \/ 11T - OD 52mm \/ 2","offer_id":52442988609810,"sku":"PHGLFBLTYGLBZSJ058242x2","price":51.8,"currency_code":"USD","in_stock":true},{"title":"4Modul \/ 11T - OD 52mm \/ 3","offer_id":52442988642578,"sku":"PHGLFBLTYGLBZSJ058242x3","price":77.14,"currency_code":"USD","in_stock":true},{"title":"4Modul \/ 12T - OD 56mm \/ 1","offer_id":52442988675346,"sku":"PHGLFBLTYGLBZSJ058243x1","price":33.44,"currency_code":"USD","in_stock":true},{"title":"4Modul \/ 12T - OD 56mm \/ 2","offer_id":52442988708114,"sku":"PHGLFBLTYGLBZSJ058243x2","price":65.77,"currency_code":"USD","in_stock":true},{"title":"4Modul \/ 12T - OD 56mm \/ 3","offer_id":52442988740882,"sku":"PHGLFBLTYGLBZSJ058243x3","price":98.11,"currency_code":"USD","in_stock":true},{"title":"4Modul \/ 13T - OD 60mm \/ 1","offer_id":52442988773650,"sku":"PHGLFBLTYGLBZSJ058244x1","price":35.97,"currency_code":"USD","in_stock":true},{"title":"4Modul \/ 13T - OD 60mm \/ 2","offer_id":52442988806418,"sku":"PHGLFBLTYGLBZSJ058244x2","price":70.82,"currency_code":"USD","in_stock":true},{"title":"4Modul \/ 13T - OD 60mm \/ 3","offer_id":52442988839186,"sku":"PHGLFBLTYGLBZSJ058244x3","price":105.67,"currency_code":"USD","in_stock":true},{"title":"4Modul \/ 14T - OD 64mm \/ 1","offer_id":52442988871954,"sku":"PHGLFBLTYGLBZSJ058245x1","price":48.61,"currency_code":"USD","in_stock":true},{"title":"4Modul \/ 14T - OD 64mm \/ 2","offer_id":52442988904722,"sku":"PHGLFBLTYGLBZSJ058245x2","price":96.1,"currency_code":"USD","in_stock":true},{"title":"4Modul \/ 15T - OD 68mm \/ 1","offer_id":52442988937490,"sku":"PHGLFBLTYGLBZSJ058246x1","price":50.88,"currency_code":"USD","in_stock":true},{"title":"4Modul \/ 15T - OD 68mm \/ 2","offer_id":52442988970258,"sku":"PHGLFBLTYGLBZSJ058246x2","price":100.64,"currency_code":"USD","in_stock":true},{"title":"4Modul \/ 16T - OD 72mm \/ 1","offer_id":52442989003026,"sku":"PHGLFBLTYGLBZSJ058247x1","price":56.79,"currency_code":"USD","in_stock":true},{"title":"4Modul \/ 17T - OD 76mm \/ 1","offer_id":52442989035794,"sku":"PHGLFBLTYGLBZSJ058248x1","price":61.16,"currency_code":"USD","in_stock":true},{"title":"4Modul \/ 18T - OD 80mm \/ 1","offer_id":52442989068562,"sku":"PHGLFBLTYGLBZSJ058249x1","price":77.38,"currency_code":"USD","in_stock":true},{"title":"4Modul \/ 19T - OD 84mm \/ 1","offer_id":52442989101330,"sku":"PHGLFBLTYGLBZSJ058250x1","price":82.38,"currency_code":"USD","in_stock":true},{"title":"4Modul \/ 20T - OD 88mm \/ 1","offer_id":52442989134098,"sku":"PHGLFBLTYGLBZSJ058251x1","price":82.89,"currency_code":"USD","in_stock":true},{"title":"4Modul \/ 21T - OD 92mm \/ 1","offer_id":52442989166866,"sku":"PHGLFBLTYGLBZSJ058252x1","price":99.78,"currency_code":"USD","in_stock":true},{"title":"4Modul \/ 22T - OD 96mm \/ 1","offer_id":52442989199634,"sku":"PHGLFBLTYGLBZSJ058253x1","price":106.27,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0884\/8936\/1682\/files\/Picture5of8_ad840f62-7239-4556-be21-2d0941d4165a.jpg?v=1783953633","url":"https:\/\/homediyer.com\/products\/4-modulus-spur-gear-10t-22t-flat-gear-45-steel-transmission-gears-od-48-96mm","provider":"HomeDIYer","version":"1.0","type":"link"}