{"product_id":"0-5-mod-42t-spur-gears-steel-pinion-gears-metal-spur-transmission-gear-45-steel","title":"0.5 Mod 42T Spur Gears Steel Pinion Gears Metal Spur Transmission Gear 45 Steel","description":"\u003cdiv class=\"hdiy-desc\"\u003e\n\n\u003cdiv class=\"hdiy-overview\"\u003e\n\u003ch2\u003e0.5 Mod 42T Steel Spur Gears — Reliable Pinion Gear for Precision Transmission\u003c\/h2\u003e\n\u003cp\u003eWhen a stripped or undersized gear brings your build to a halt, you need a replacement that fits right the first time. These 0.5 module 42-tooth steel spur gears are designed for makers, robotics builders, RC hobbyists, and small-machine engineers who demand consistent mesh accuracy and long service life from every drivetrain component.\u003c\/p\u003e\n\u003cp\u003eEach gear is machined from 45# carbon steel, delivering a tensile strength typically in the 600–800 MPa range with good wear resistance. The module is 0.5 (pitch diameter = 21 mm \/ ~0.827 in), tooth count is 42T, and bore options span 6 mm, 8 mm, and 10 mm to suit a range of shaft diameters. Face width is typically 5–8 mm (~0.20–0.31 in) depending on the variant.\u003c\/p\u003e\n\u003cp\u003eTypical use cases include DC gearmotor output stages in desktop CNC machines, servo-driven steering racks in 1\/10-scale RC vehicles, and compact conveyor or indexing mechanisms in DIY automation projects — anywhere a low-module spur gear for small shaft drives is required.\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 spur or pinion gear. Bore sizes 6 mm, 8 mm, and 10 mm suit standard motor and gearbox output shafts. Confirm shaft diameter and keyway requirements before ordering.\n\u003c\/div\u003e\n\n\u003cdiv class=\"hdiy-features\"\u003e\n\u003ch2\u003e✅ Key Features of These 0.5 Mod 42T Steel Spur Gears\u003c\/h2\u003e\n\u003cdiv class=\"hdiy-list\"\u003e\n  \u003cdiv\u003e\n\u003cspan class=\"hdiy-icon\"\u003e🔩\u003c\/span\u003e\u003cstrong\u003e45# Carbon Steel Construction\u003c\/strong\u003e\u003cbr\u003eMachined from 45# carbon steel for solid load-bearing capacity and resistance to tooth deformation under cyclic stress — a dependable choice for continuous-duty transmission applications.\u003c\/div\u003e\n  \u003cdiv\u003e\n\u003cspan class=\"hdiy-icon\"\u003e📐\u003c\/span\u003e\u003cstrong\u003e0.5 Module, 42-Tooth Profile\u003c\/strong\u003e\u003cbr\u003eStandard 0.5 mod tooth geometry ensures accurate mesh with any compatible 0.5-module gear, minimising backlash and noise in precision motion systems.\u003c\/div\u003e\n  \u003cdiv\u003e\n\u003cspan class=\"hdiy-icon\"\u003e🎯\u003c\/span\u003e\u003cstrong\u003eThree Bore Options: 6 \/ 8 \/ 10 mm\u003c\/strong\u003e\u003cbr\u003eSelect the bore that matches your motor or gearbox shaft — 6 mm, 8 mm, or 10 mm — for a direct, secure fit without additional machining in most standard applications.\u003c\/div\u003e\n  \u003cdiv\u003e\n\u003cspan class=\"hdiy-icon\"\u003e📦\u003c\/span\u003e\u003cstrong\u003eFlexible Pack Quantities (1–50 pcs)\u003c\/strong\u003e\u003cbr\u003eOrder a single gear for a one-off repair or up to 50 pieces for production runs and spares inventory, with per-unit cost decreasing at higher quantities.\u003c\/div\u003e\n  \u003cdiv\u003e\n\u003cspan class=\"hdiy-icon\"\u003e🔄\u003c\/span\u003e\u003cstrong\u003eConsistent Tooth Accuracy\u003c\/strong\u003e\u003cbr\u003eGears are produced to repeatable dimensional tolerances, supporting smooth, low-vibration power transfer in robotics, RC drivetrains, and compact automation equipment.\u003c\/div\u003e\n  \u003cdiv\u003e\n\u003cspan class=\"hdiy-icon\"\u003e🛠️\u003c\/span\u003e\u003cstrong\u003eBroad DIY \u0026amp; Maker Compatibility\u003c\/strong\u003e\u003cbr\u003eSuited for desktop CNC builds, servo-driven RC steering, small conveyor indexers, and any project requiring a compact 0.5-module spur gear for small shaft drives.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"hdiy-table-wrap\"\u003e\n\u003ch2\u003e📐 Technical Specifications — 0.5 Mod Spur Gears\u003c\/h2\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\u003e42T\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003ePitch Diameter\u003c\/th\u003e\n\u003ctd\u003e21 mm (~0.827 in)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eBore Diameter\u003c\/th\u003e\n\u003ctd\u003e6 mm \/ 8 mm \/ 10 mm (see 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\u003e45# Carbon Steel\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003ePressure Angle\u003c\/th\u003e\n\u003ctd\u003e20° (standard)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eGear Type\u003c\/th\u003e\n\u003ctd\u003eSpur Gear (external)\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\u003ePack Quantity\u003c\/th\u003e\n\u003ctd\u003e1 \/ 5 \/ 10 \/ 15 \/ 20 \/ 30 \/ 40 \/ 50 pcs\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 gearbox output shaft diameter with a caliper. Select the 6 mm bore for shafts up to 6 mm, 8 mm for shafts up to 8 mm, and 10 mm for shafts up to 10 mm. If your shaft uses a keyway or set-screw flat, confirm the gear hub depth is sufficient before ordering.\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 gears?\u003c\/summary\u003e\n  \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eYes. Any gear with a 0.5 module and a 20° pressure angle will mesh correctly with these 42T gears. Module and pressure angle must match between mating gears — tooth count only affects the gear ratio, not compatibility.\u003c\/p\u003e\u003c\/div\u003e\n\u003c\/details\u003e\n\n\u003cdetails\u003e\n  \u003csummary\u003eHow strong are these gears under load?\u003c\/summary\u003e\n  \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003e45# carbon steel typically achieves a tensile strength of 600–800 MPa after standard heat treatment, making it suitable for moderate-load continuous-duty applications such as RC drivetrains, small servo mechanisms, and desktop automation. For very high-torque or shock-load environments, consider a larger module gear.\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# carbon steel has moderate corrosion resistance. For indoor or dry environments these gears perform well with light lubrication. For humid or outdoor use, apply a suitable gear grease or consider a stainless-steel alternative to extend service life.\u003c\/p\u003e\u003c\/div\u003e\n\u003c\/details\u003e\n\n\u003cdetails\u003e\n  \u003csummary\u003eWhat gear ratio can I achieve with a 42T spur gear?\u003c\/summary\u003e\n  \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eGear ratio is determined by pairing this 42T gear with a pinion of a different tooth count. For example, pairing with a 14T pinion gives a 3:1 reduction ratio. Pair with any 0.5-module gear of your chosen tooth count to achieve the ratio your application requires.\u003c\/p\u003e\u003c\/div\u003e\n\u003c\/details\u003e\n\n\u003cdetails\u003e\n  \u003csummary\u003eHow many pieces should I order for a project?\u003c\/summary\u003e\n  \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eFor a single-axis build or repair, 1 pc is sufficient. For multi-axis machines or production runs, ordering 10–50 pcs reduces per-unit cost and ensures you have spares on hand. The quantity selector above shows the price per pack so you can compare before adding to cart.\u003c\/p\u003e\u003c\/div\u003e\n\u003c\/details\u003e\n\n\u003cdetails\u003e\n  \u003csummary\u003eDo these gears require lubrication?\u003c\/summary\u003e\n  \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eYes, light lubrication is recommended for all steel spur gears to reduce wear and noise. Apply a thin film of gear grease or light machine oil to the tooth faces during installation and re-lubricate periodically based on duty cycle and operating speed.\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–Bore 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 bore size for my motor shaft?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Measure your motor or gearbox output shaft diameter with a caliper. Select the 6 mm bore for shafts up to 6 mm, 8 mm for shafts up to 8 mm, and 10 mm for shafts up to 10 mm. If your shaft uses a keyway or set-screw flat, confirm the gear hub depth is sufficient before ordering.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Will this gear mesh with my existing 0.5-module gears?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Yes. Any gear with a 0.5 module and a 20° pressure angle will mesh correctly with these 42T gears. Module and pressure angle must match between mating gears — tooth count only affects the gear ratio, not compatibility.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"How strong are these gears under load?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"45# carbon steel typically achieves a tensile strength of 600–800 MPa after standard heat treatment, making it suitable for moderate-load continuous-duty applications such as RC drivetrains, small servo mechanisms, and desktop automation.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Are these gears corrosion-resistant?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"45# carbon steel has moderate corrosion resistance. For indoor or dry environments these gears perform well with light lubrication. For humid or outdoor use, apply a suitable gear grease or consider a stainless-steel alternative.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"What gear ratio can I achieve with a 42T spur gear?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Gear ratio is determined by pairing this 42T gear with a pinion of a different tooth count. For example, pairing with a 14T pinion gives a 3:1 reduction ratio.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"How many pieces should I order for a project?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"For a single-axis build or repair, 1 pc is sufficient. For multi-axis machines or production runs, ordering 10–50 pcs reduces per-unit cost and ensures you have spares on hand.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Do these gears require lubrication?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Yes, light lubrication is recommended for all steel spur gears to reduce wear and noise. Apply a thin film of gear grease or light machine oil to the tooth faces during installation and re-lubricate periodically based on duty cycle and operating speed.\"\n      }\n    }\n  ]\n}\n\u003c\/script\u003e","brand":"HomeDIYer","offers":[{"title":"42T-6mm \/ 1","offer_id":52443375272210,"sku":"GLFBMWXGLCDPJ00074x1","price":4.58,"currency_code":"USD","in_stock":true},{"title":"42T-6mm \/ 5","offer_id":52443375304978,"sku":"GLFBMWXGLCDPJ00074x5","price":19.53,"currency_code":"USD","in_stock":true},{"title":"42T-6mm \/ 10","offer_id":52443375337746,"sku":"GLFBMWXGLCDPJ00074x10","price":38.43,"currency_code":"USD","in_stock":true},{"title":"42T-6mm \/ 15","offer_id":52443375370514,"sku":"GLFBMWXGLCDPJ00074x15","price":57.34,"currency_code":"USD","in_stock":true},{"title":"42T-6mm \/ 20","offer_id":52443375403282,"sku":"GLFBMWXGLCDPJ00074x20","price":76.24,"currency_code":"USD","in_stock":true},{"title":"42T-6mm \/ 30","offer_id":52443375436050,"sku":"GLFBMWXGLCDPJ00074x30","price":114.06,"currency_code":"USD","in_stock":true},{"title":"42T-6mm \/ 40","offer_id":52443375468818,"sku":"GLFBMWXGLCDPJ00074x40","price":151.87,"currency_code":"USD","in_stock":true},{"title":"42T-6mm \/ 50","offer_id":52443375501586,"sku":"GLFBMWXGLCDPJ00074x50","price":189.68,"currency_code":"USD","in_stock":true},{"title":"42T-8mm \/ 1","offer_id":52443375534354,"sku":"GLFBMWXGLCDPJ00075x1","price":4.58,"currency_code":"USD","in_stock":true},{"title":"42T-8mm \/ 5","offer_id":52443375567122,"sku":"GLFBMWXGLCDPJ00075x5","price":19.53,"currency_code":"USD","in_stock":true},{"title":"42T-8mm \/ 10","offer_id":52443375599890,"sku":"GLFBMWXGLCDPJ00075x10","price":38.43,"currency_code":"USD","in_stock":true},{"title":"42T-8mm \/ 15","offer_id":52443375632658,"sku":"GLFBMWXGLCDPJ00075x15","price":57.34,"currency_code":"USD","in_stock":true},{"title":"42T-8mm \/ 20","offer_id":52443375665426,"sku":"GLFBMWXGLCDPJ00075x20","price":76.24,"currency_code":"USD","in_stock":true},{"title":"42T-8mm \/ 30","offer_id":52443375698194,"sku":"GLFBMWXGLCDPJ00075x30","price":114.06,"currency_code":"USD","in_stock":true},{"title":"42T-8mm \/ 40","offer_id":52443375730962,"sku":"GLFBMWXGLCDPJ00075x40","price":151.87,"currency_code":"USD","in_stock":true},{"title":"42T-8mm \/ 50","offer_id":52443375763730,"sku":"GLFBMWXGLCDPJ00075x50","price":189.68,"currency_code":"USD","in_stock":true},{"title":"42T-10mm \/ 1","offer_id":52443375796498,"sku":"GLFBMWXGLCDPJ00076x1","price":4.58,"currency_code":"USD","in_stock":true},{"title":"42T-10mm \/ 5","offer_id":52443375829266,"sku":"GLFBMWXGLCDPJ00076x5","price":19.53,"currency_code":"USD","in_stock":true},{"title":"42T-10mm \/ 10","offer_id":52443375862034,"sku":"GLFBMWXGLCDPJ00076x10","price":38.43,"currency_code":"USD","in_stock":true},{"title":"42T-10mm \/ 15","offer_id":52443375894802,"sku":"GLFBMWXGLCDPJ00076x15","price":57.34,"currency_code":"USD","in_stock":true},{"title":"42T-10mm \/ 20","offer_id":52443375927570,"sku":"GLFBMWXGLCDPJ00076x20","price":76.24,"currency_code":"USD","in_stock":true},{"title":"42T-10mm \/ 30","offer_id":52443375960338,"sku":"GLFBMWXGLCDPJ00076x30","price":114.06,"currency_code":"USD","in_stock":true},{"title":"42T-10mm \/ 40","offer_id":52443375993106,"sku":"GLFBMWXGLCDPJ00076x40","price":151.87,"currency_code":"USD","in_stock":true},{"title":"42T-10mm \/ 50","offer_id":52443376025874,"sku":"GLFBMWXGLCDPJ00076x50","price":189.68,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0884\/8936\/1682\/files\/Picture_1_of_7_1.jpg?v=1784113081","url":"https:\/\/homediyer.com\/products\/0-5-mod-42t-spur-gears-steel-pinion-gears-metal-spur-transmission-gear-45-steel","provider":"HomeDIYer","version":"1.0","type":"link"}