{"product_id":"straight-spur-gear-45-steel-motor-gears-2mod-17t-1mod-20t","title":"Straight Spur Gear 45# Steel Motor Gears 2Mod 17T 20Pcs and 1Mod 20T 20Pcs","description":"\u003cdiv class=\"hdiy-desc\"\u003e\n\n  \u003cdiv class=\"hdiy-overview\"\u003e\n    \u003ch2\u003eStraight Spur Gear 45# Steel — Reliable Motor Gears for Precision Drive Systems\u003c\/h2\u003e\n    \u003cp\u003eWhen a slipping or mismatched gear brings your build to a halt, you need components machined to spec — not close enough. Engineers, robotics builders, and DIY automation enthusiasts working on compact drive trains demand gears that mesh cleanly, hold torque, and resist wear over thousands of cycles. This combo pack delivers two proven module sizes in one order, eliminating the sourcing friction of matching gears across separate listings.\u003c\/p\u003e\n    \u003cp\u003eThis set includes two gear types: 2Mod 17-tooth spur gears (20 pieces) and 1Mod 20-tooth spur gears (20 pieces), totaling 40 pieces. Both are machined from 45# medium-carbon steel, a material known for its balance of machinability and mechanical strength. The 2Mod gears have a reference pitch diameter of 34 mm (~1.34 in) and a tooth height of approximately 4.5 mm; the 1Mod gears have a reference pitch diameter of 20 mm (~0.79 in) and a tooth height of approximately 2.25 mm. Bore diameter varies by variant — see variant options for exact bore specs.\u003c\/p\u003e\n    \u003cp\u003eTypical applications include small robotic arm joints requiring 1Mod 20T pinion-to-gear reduction, 2Mod 17T stage drives in CNC axis assemblies, and multi-stage gearbox prototypes where both module sizes are needed in a single compact enclosure. Long-tail use cases: DIY motorized camera slider gear drive, 3D printer extruder gear replacement, tabletop automation conveyor reduction stage.\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 2Mod gears mesh with any standard Module 2 spur or helical gear; 1Mod gears mesh with any standard Module 1 spur gear. Verify bore diameter and keyway requirements before ordering.\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"hdiy-features\"\u003e\n    \u003ch2\u003e✅ Key Features of These 45# Steel Straight 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\u003eDual-Module Combo Pack\u003c\/strong\u003e\n        \u003cp\u003eIncludes 20 pcs of 2Mod 17T and 20 pcs of 1Mod 20T in one order — ideal for multi-stage gearbox builds without separate sourcing.\u003c\/p\u003e\n      \u003c\/div\u003e\n      \u003cdiv\u003e\n        \u003cspan class=\"hdiy-icon\"\u003e🏗️\u003c\/span\u003e\n        \u003cstrong\u003e45# Medium-Carbon Steel Construction\u003c\/strong\u003e\n        \u003cp\u003eMachined from 45# steel for a practical balance of tensile strength, wear resistance, and ease of secondary machining such as bore enlargement or keyway cutting.\u003c\/p\u003e\n      \u003c\/div\u003e\n      \u003cdiv\u003e\n        \u003cspan class=\"hdiy-icon\"\u003e📐\u003c\/span\u003e\n        \u003cstrong\u003eStandard Module Tooth Profile\u003c\/strong\u003e\n        \u003cp\u003eFull-depth involute tooth form per standard module specifications ensures smooth meshing and interchangeability with other standard-module gears in your drivetrain.\u003c\/p\u003e\n      \u003c\/div\u003e\n      \u003cdiv\u003e\n        \u003cspan class=\"hdiy-icon\"\u003e⚡\u003c\/span\u003e\n        \u003cstrong\u003eConsistent Tooth Accuracy\u003c\/strong\u003e\n        \u003cp\u003eMachined tooth flanks reduce backlash and vibration in motor-driven applications, supporting quieter operation in robotics and automation stages.\u003c\/p\u003e\n      \u003c\/div\u003e\n      \u003cdiv\u003e\n        \u003cspan class=\"hdiy-icon\"\u003e🔄\u003c\/span\u003e\n        \u003cstrong\u003eVersatile Bore Options\u003c\/strong\u003e\n        \u003cp\u003eAvailable in multiple bore diameters to fit common motor shaft sizes — select your required bore from the variant options above before adding to cart.\u003c\/p\u003e\n      \u003c\/div\u003e\n      \u003cdiv\u003e\n        \u003cspan class=\"hdiy-icon\"\u003e📦\u003c\/span\u003e\n        \u003cstrong\u003eBulk Quantity for Prototyping\u003c\/strong\u003e\n        \u003cp\u003e20 pieces per module size supports iterative prototyping, spare-part stocking, and small-batch production runs without reordering delays.\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 — Straight Spur Gears\u003c\/h2\u003e\n    \u003ctable\u003e\n      \u003ctbody\u003e\n        \u003ctr\u003e\n\u003cth\u003eMaterial\u003c\/th\u003e\n\u003ctd\u003e45# Medium-Carbon Steel\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eModule (Gear 1)\u003c\/th\u003e\n\u003ctd\u003e2 Mod\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eTooth Count (Gear 1)\u003c\/th\u003e\n\u003ctd\u003e17T\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eQuantity (Gear 1)\u003c\/th\u003e\n\u003ctd\u003e20 pcs\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eReference Pitch Diameter (Gear 1)\u003c\/th\u003e\n\u003ctd\u003e34 mm (~1.34 in)\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eModule (Gear 2)\u003c\/th\u003e\n\u003ctd\u003e1 Mod\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eTooth Count (Gear 2)\u003c\/th\u003e\n\u003ctd\u003e20T\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eQuantity (Gear 2)\u003c\/th\u003e\n\u003ctd\u003e20 pcs\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eReference Pitch Diameter (Gear 2)\u003c\/th\u003e\n\u003ctd\u003e20 mm (~0.79 in)\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eTooth Profile\u003c\/th\u003e\n\u003ctd\u003eStandard Involute (Full Depth)\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\u003eBore Diameter\u003c\/th\u003e\n\u003ctd\u003eSee 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\u003eSurface Finish\u003c\/th\u003e\n\u003ctd\u003eSee variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eTotal Pieces per Set\u003c\/th\u003e\n\u003ctd\u003e40 pcs (20 + 20)\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 between the 2Mod 17T and 1Mod 20T gears for my project?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eModule size determines which gears can mesh together — a 2Mod gear can only mesh with another 2Mod gear, and a 1Mod gear only with 1Mod. Choose based on the module of the mating gear already in your drivetrain. The 2Mod 17T is suited for higher-torque, lower-speed stages; the 1Mod 20T fits compact, higher-speed reduction stages where space is limited.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eWhat is the tensile strength of 45# steel, and is it strong enough for my motor drive?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003e45# medium-carbon steel has a typical tensile strength of approximately 600–800 MPa in the normalized condition, making it suitable for moderate-load motor drive applications such as robotics joints, small CNC axes, and automation conveyors. For very high-shock or high-RPM applications, consider whether a heat-treated or alloy steel gear would better suit your load requirements.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eAre these gears corrosion-resistant? Can I use them in humid or outdoor environments?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003e45# steel is not inherently corrosion-resistant. In humid or outdoor environments, we recommend applying a light machine oil coating, using a protective enclosure, or selecting a variant with a surface treatment if available. For environments with direct water exposure, stainless steel or plastic gears may be more appropriate.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eWill these gears fit standard motor shafts from common robotics platforms?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eBore diameter compatibility depends on the specific variant you select. Common bore sizes for this type of gear range from 4 mm to 12 mm. Check the variant options above for available bore diameters and match them to your motor shaft diameter. If your shaft requires a keyway or set-screw flat, verify that the selected variant includes it or that the bore can be machined to your spec.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eCan I use these gears together in the same gearbox stage?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eThe 2Mod and 1Mod gears cannot mesh directly with each other — they must be used in separate stages. However, both can be incorporated into a multi-stage gearbox where each stage uses its own matching module pair. This combo pack is designed for builders who need both module sizes for different stages of the same assembly.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eHow do I calculate the center distance between two meshing gears from this set?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eFor standard spur gears, center distance = (T1 + T2) × Module \/ 2. For two 2Mod gears where one is 17T and the mating gear is N teeth: center distance = (17 + N) × 2 \/ 2 mm. For 1Mod gears: center distance = (20 + N) × 1 \/ 2 mm. This formula assumes standard (non-profile-shifted) gears with a 20° pressure angle.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eWhat is the best way to secure these gears to a shaft?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eThe most common methods are a set screw through the hub (if the variant includes a tapped hole), a press fit for tight-tolerance bores, or a shaft key and keyway. Check the variant description for hub features. For prototyping, a set-screw hub is the most convenient; for production, a keyed or interference-fit bore provides more reliable torque transmission.\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 diameter and module 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 between the 2Mod 17T and 1Mod 20T gears for my project?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Module size determines which gears can mesh together — a 2Mod gear can only mesh with another 2Mod gear, and a 1Mod gear only with 1Mod. Choose based on the module of the mating gear already in your drivetrain. The 2Mod 17T is suited for higher-torque, lower-speed stages; the 1Mod 20T fits compact, higher-speed reduction stages where space is limited.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"What is the tensile strength of 45# steel, and is it strong enough for my motor drive?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"45# medium-carbon steel has a typical tensile strength of approximately 600–800 MPa in the normalized condition, making it suitable for moderate-load motor drive applications such as robotics joints, small CNC axes, and automation conveyors.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Are these gears corrosion-resistant? Can I use them in humid or outdoor environments?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"45# steel is not inherently corrosion-resistant. In humid or outdoor environments, apply a light machine oil coating or use a protective enclosure. For direct water exposure, stainless steel or plastic gears may be more appropriate.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Will these gears fit standard motor shafts from common robotics platforms?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Bore diameter compatibility depends on the specific variant you select. Common bore sizes range from 4 mm to 12 mm. Check the variant options above for available bore diameters and match them to your motor shaft diameter.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Can I use these gears together in the same gearbox stage?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"The 2Mod and 1Mod gears cannot mesh directly with each other — they must be used in separate stages. Both can be incorporated into a multi-stage gearbox where each stage uses its own matching module pair.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"How do I calculate the center distance between two meshing gears from this set?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"For standard spur gears, center distance = (T1 + T2) × Module \/ 2. For 2Mod gears with 17T: center distance = (17 + N) × 2 \/ 2 mm. For 1Mod gears with 20T: center distance = (20 + N) × 1 \/ 2 mm.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"What is the best way to secure these gears to a shaft?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Common methods include a set screw through the hub, a press fit for tight-tolerance bores, or a shaft key and keyway. Check the variant description for hub features. For prototyping, a set-screw hub is most convenient; for production, a keyed or interference-fit bore provides more reliable torque transmission.\"\n      }\n    }\n  ]\n}\n\u003c\/script\u003e","brand":"HomeDIYer","offers":[{"title":"Default Title","offer_id":52442997424402,"sku":"NHHCLDZ1161","price":225.96,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0884\/8936\/1682\/files\/Picture2of8_4f7a6a2a-e227-4d2e-84ea-3876302a206b.jpg?v=1783953668","url":"https:\/\/homediyer.com\/products\/straight-spur-gear-45-steel-motor-gears-2mod-17t-1mod-20t","provider":"HomeDIYer","version":"1.0","type":"link"}