{"id":1509,"date":"2026-07-14T05:54:01","date_gmt":"2026-07-14T05:54:01","guid":{"rendered":"https:\/\/gearrack.top\/product\/heavy-machinery-double-helical-gear-42crmo-50-55-hrc\/"},"modified":"2026-07-14T05:54:25","modified_gmt":"2026-07-14T05:54:25","slug":"heavy-machinery-double-helical-gear-42crmo-50-55-hrc","status":"publish","type":"product","link":"https:\/\/gearrack.top\/it\/product\/heavy-machinery-double-helical-gear-42crmo-50-55-hrc\/","title":{"rendered":"Heavy Machinery Double Helical Gear – 42CrMo, 50-55 HRC"},"content":{"rendered":"
\n

<\/p>\n

Product Overview<\/h2>\n
\n
\n \"Heavy\n <\/div>\n
\n

Heavy machinery double helical gears<\/strong> are the gear form of choice when two requirements must be satisfied simultaneously: the smooth, quiet, high-contact-ratio engagement of a helical gear, and the elimination of the axial thrust force that a single helical gear imposes on shaft bearings and housings. By placing two helical tooth sets of opposite hand side by side on the same gear body, the axial forces from each half cancel \u2014 the shaft sees only radial loads. In heavy machinery drives where the shaft and bearing arrangement is already loaded by the equipment’s working forces, eliminating gear axial thrust simplifies bearing selection, extends bearing life, and allows more compact housing designs.<\/p>\n

Korea Ever-Power produces heavy machinery double helical gears<\/a> in cast steel and alloy steel to customer drawings or samples. Material is fully customisable across the standard alloy steel grades \u2014 from 45# carbon steel for cost-effective medium-load applications through 40CrNiMoA for the highest-load heavy industrial drives. Heat treatment by quenching and tempering produces a soft tooth surface (\u2264350 HB) with the core toughness needed to absorb the shock and reversing loads typical of crane drives, conveyor head drives, and rolling mill pinion stands.<\/p>\n<\/p><\/div>\n<\/div>\n

Korea Ever-Power provides parts design, prototyping, mould design, mass production, and internal assembly services for these gears. Experience ranges from simple configurations to technically demanding parts requiring close-tolerance bore, keyway, and face geometry in large cast steel forgings. Custom helix angle is available \u2014 the gear geometry is fully defined by the customer’s drawing, and the cross-specification is verified using AutoCAD or SolidWorks before production begins.<\/p>\n

<\/p>\n

Technical Specifications<\/h2>\n
\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Heavy Machinery Double Helical Gear \u2014 Specifications<\/th>\n<\/tr>\n<\/thead>\n
Gear Shape<\/strong><\/td>\nDouble Helical Gear (herringbone)<\/td>\n<\/tr>\n
Gear Position<\/strong><\/td>\nExternal gear<\/td>\n<\/tr>\n
Manufacturing Method<\/strong><\/td>\nCut gear \u2014 gear hobbing; gear grinding not included in standard configuration<\/td>\n<\/tr>\n
Pressure Angle<\/strong><\/td>\n20\u00b0<\/td>\n<\/tr>\n
Helix Angle<\/strong><\/td>\nCustom made to drawing \u2014 both helical halves at equal and opposite angle<\/td>\n<\/tr>\n
Heat Treatment<\/strong><\/td>\nQuenching and tempering (soft tooth surface)<\/td>\n<\/tr>\n
Surface Hardness<\/strong><\/td>\nOptions \u2014 specify HB range in drawing; standard Q&T range \u2264350 HB<\/td>\n<\/tr>\n
Gear Accuracy Grade<\/strong><\/td>\nGrade 8\u20139 per ISO 1328<\/td>\n<\/tr>\n
Material<\/strong><\/td>\nCast steel or alloy steel \u2014 custom per drawing (see cross-reference table)<\/td>\n<\/tr>\n
Applications<\/strong><\/td>\nMotor, electric cars, motorcycle, machinery, marine, agricultural machinery, car, heavy industry<\/td>\n<\/tr>\n
Trademark<\/strong><\/td>\nOEM \u2014 customer logo marking available<\/td>\n<\/tr>\n
Mass Production Lead Time<\/strong><\/td>\n15\u201320 working days (quantity-dependent)<\/td>\n<\/tr>\n
Custom Transmission Service<\/strong><\/td>\nDesign, prototyping, mould design, mass production, assembly \u2014 full service<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

Custom Transmission Parts \u2014 Heavy Duty Double Helical Gear Configuration<\/strong><\/p>\n

\n\n\n\n\n\n\n\n\n\n\n\n\n
Parameter<\/th>\nValue<\/th>\n<\/tr>\n<\/thead>\n
Material<\/strong><\/td>\nCustom made (alloy steel or cast steel per drawing)<\/td>\n<\/tr>\n
Gear Hobbing<\/strong><\/td>\n\u2714 Standard manufacturing method<\/td>\n<\/tr>\n
Gear Grinding<\/strong><\/td>\nNot included in standard configuration \u2014 available on request for higher accuracy grades<\/td>\n<\/tr>\n
Pressure Angle<\/strong><\/td>\n20\u00b0<\/td>\n<\/tr>\n
Helix Angle<\/strong><\/td>\nCustom made per drawing<\/td>\n<\/tr>\n
Heat Treatment<\/strong><\/td>\nQuenching and tempering<\/td>\n<\/tr>\n
Surface Hardness<\/strong><\/td>\nOptions \u2014 per specification<\/td>\n<\/tr>\n
Gear Accuracy Grade<\/strong><\/td>\nGrade 8\u20139 (ISO 1328)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

Steel Grade Cross-Reference \u2014 Available Materials<\/strong><\/p>\n

\n\n\n\n\n\n\n\n\n\n\n\n\n\n
China \/ GB<\/th>\nISO<\/th>\n\u0413\u041e\u0421\u0422<\/th>\nASTM<\/th>\nJIS<\/th>\nDIN<\/th>\n<\/tr>\n<\/thead>\n
45<\/td>\nC45E4<\/td>\n45<\/td>\n1045<\/td>\nS45C<\/td>\nCK45<\/td>\n<\/tr>\n
40Cr<\/td>\n41Cr4<\/td>\n40X<\/td>\n5140<\/td>\nSCr440<\/td>\n41Cr4<\/td>\n<\/tr>\n
20CrMo<\/td>\n18CrMo4<\/td>\n20\u0425\u041c<\/td>\n4118<\/td>\nSCM22<\/td>\n25CrMo4<\/td>\n<\/tr>\n
42CrMo<\/td>\n42CrMo4<\/td>\n38XM<\/td>\n4140<\/td>\nSCM440<\/td>\n42CrMo4<\/td>\n<\/tr>\n
20CrMnTi<\/td>\n\u2014<\/td>\n18X\u0413\u0422<\/td>\n\u2014<\/td>\nSMK22<\/td>\n\u2014<\/td>\n<\/tr>\n
20Cr2Ni4<\/td>\n\u2014<\/td>\n20X2H4A<\/td>\n\u2014<\/td>\n\u2014<\/td>\n\u2014<\/td>\n<\/tr>\n
20CrNiMo<\/td>\n20CrNiMo2<\/td>\n20XHM<\/td>\n8720<\/td>\nSNCM220<\/td>\n21NiCrMo2<\/td>\n<\/tr>\n
40CrNiMoA<\/td>\n\u2014<\/td>\n40XH2MA<\/td>\n4340<\/td>\nSNCM439<\/td>\n40NiCrMo6<\/td>\n<\/tr>\n
20CrNi2Mo<\/td>\n20NiCrMo7<\/td>\n20XH2MA<\/td>\n4320<\/td>\nSNCM420<\/td>\n\u2014<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

<\/p>\n

Key Advantages of Double Helical Gears in Heavy Machinery<\/h2>\n

\"Ever-Power<\/p>\n

\n
\n

Zero Net Axial Thrust<\/h3>\n

The two helical halves in opposite hands produce equal and opposite axial thrust forces that cancel internally. Shaft bearings and housings in heavy machinery drives see only radial loads from the gear \u2014 no axial force that would require thrust bearings or additional housing rigidity.<\/p>\n<\/p><\/div>\n

\n

High Contact Ratio<\/h3>\n

Double helical gears provide a higher effective contact ratio than single helical gears of the same face width, because both tooth sets contribute to load sharing simultaneously. At any instant, multiple tooth pairs on both the left and right helical halves are in contact, reducing the peak load on any individual tooth pair.<\/p>\n<\/p><\/div>\n

\n

Smooth, Stable Operation<\/h3>\n

The progressive tooth engagement of helical teeth \u2014 combined with the load distribution across both tooth sets \u2014 produces stable, low-vibration operation even at the low speeds and high torques characteristic of heavy machinery main drives. The quenched-and-tempered soft tooth surface is well matched to the moderate-speed, high-torque duty of heavy industrial gearboxes.<\/p>\n<\/p><\/div>\n

\n

Shock and Reversing Load Tolerance<\/h3>\n

Quenching and tempering produces a through-hardened core with high impact energy \u2014 the tooth root can absorb shock loads from crane hook engagement, press working strokes, and mill bite events without fracture. This is the engineering reason that soft tooth surface gears remain the preference in heavy machinery drives despite their lower surface hardness compared with carburised gears.<\/p>\n<\/p><\/div>\n<\/div>\n

<\/p>\n

Applications<\/h2>\n

\"types<\/p>\n

\n
\n
\ufe0f<\/div>\n

Industrial Cranes<\/h3>\n

Hoisting gearboxes, bridge travel drives, and slewing ring drives in overhead cranes and shipyard gantry cranes. The zero-thrust property is particularly valuable in crane hoisting drives, where inertial thrust loads at start and stop would otherwise stress the housing mounting flanges.<\/p>\n<\/p><\/div>\n

\n
\u26cf\ufe0f<\/div>\n

Mining Equipment<\/h3>\n

Conveyor head drive gearboxes, bucket wheel slewing drives, and hoist drum drives in underground and surface mining equipment. Cast steel double helical gears are appropriate for the large module sizes used in mining drives where forged blank availability may be a constraint.<\/p>\n<\/p><\/div>\n

\n
<\/div>\n

Rolling Mill Pinion Stands<\/h3>\n

Pinion stand gears in plate mills, bar mills, and section mills where the thrust-free property of double helical gears prevents the pinion housing from being pushed axially during reversing rolling passes \u2014 particularly important in reversing mills that change rotation direction at each pass.<\/p>\n<\/p><\/div>\n

\n
<\/div>\n

Marine Main Reduction<\/h3>\n

Main reduction gearboxes on cargo vessels and workboats where double helical gears are specified to eliminate propeller-shaft thrust from the gear stage and reduce noise transmission to the vessel structure. OEM configuration with customer-specified alloy grade and surface finish.<\/p>\n<\/p><\/div>\n

\n
\u2699\ufe0f<\/div>\n

Heavy Compressors<\/h3>\n

Speed increaser and speed reducer gearboxes in large industrial gas compressors and refrigeration compressors. The vibration-damping effect of the soft tooth flank and the thrust-free double helical configuration together reduce the gear-generated vibration transmitted to compressor pipework and foundations.<\/p>\n<\/p><\/div>\n

\n
<\/div>\n

Automotive & Motor Drives<\/h3>\n

Electric motor reduction stages, electric car transmission gears, and motorcycle gearbox stages in production programmes where OEM marking, alloy customisation, and short lead times \u2014 15\u201320 working days for mass production \u2014 are required alongside competitive unit pricing at volume.<\/p>\n<\/p><\/div>\n<\/div>\n

<\/p>\n

Frequently Asked Questions<\/h2>\n
\n
\n

What is the lead time for mass production?<\/p>\n

Mass production lead time is 15\u201320 working days, depending on the quantity ordered and the specific configuration. For large or complex gear sets requiring non-standard alloy grades or particularly large cast blanks, the lead time may be extended \u2014 confirm with our team at enquiry stage. Prototypes and pre-production samples are also available; lead time for these is shorter and confirmed after the drawing is reviewed.<\/p>\n<\/div>\n

\n
\n

Is gear grinding available for higher accuracy requirements?<\/p>\n

The standard configuration uses gear hobbing without grinding, producing ISO 1328 grade 8\u20139. Tooth grinding for higher accuracy (grade 6\u20137) is available on request \u2014 specify the required accuracy grade on the drawing and our team will confirm feasibility and the additional cost and lead time. For double helical gears, grinding is more complex than for single helical gears due to the requirement to access the groove between the two tooth sets, and not all configurations are grindable without design modification.<\/p>\n<\/div>\n

\n
\n

Can the helix angle be freely specified?<\/p>\n

Yes \u2014 helix angle is custom made to the customer’s drawing. Common helix angles for heavy machinery double helical gears are 15\u00b0\u201330\u00b0; angles outside this range are possible and are confirmed at the enquiry stage. The helix angle on both halves is equal in magnitude and opposite in direction \u2014 this is the defining geometry of a double helical gear and ensures the axial thrust cancellation.<\/p>\n<\/div>\n

\n
\n

What design and prototyping services are available?<\/p>\n

Korea Ever-Power offers parts design, prototyping, mould design, mass production, and internal assembly services. For customers who have a gearbox application but no finished gear drawing, our team can calculate the gear geometry from the application data (required ratio, input speed, output torque, centre distance) and produce a drawing for approval. Prototyping service is available before production tooling is committed.<\/p>\n<\/div>\n

\n
\n

Is OEM logo marking available?<\/p>\n

Yes \u2014 Korea Ever-Power provides OEM trademark services. Customer logo and part number marking can be applied to the gear web, bore, or hub face by stamping, engraving, or laser marking. Specify the required marking format and location on the drawing. Contact our team<\/a> with the drawing and marking requirements to begin the quotation process.<\/p>\n<\/div>\n<\/div>\n

<\/p>\n

Customer Reviews<\/h2>\n
\n
\n

“We manufacture overhead crane hoisting gearboxes and switched the main reduction stage from single to double helical gears sourced from Korea Ever-Power in 42CrMo, quenched and tempered. The bearing temperature in the hoisting drum shaft bearing dropped after eliminating axial thrust from the gear stage. Mass production delivery was within 18 working days for our first batch of 40 gear sets.”<\/p>\n

Kim Tae-young<\/strong>  |  Gearbox Design Engineer, Incheon Crane Systems Manufacturing  ·  Q2 2026<\/em><\/p>\n<\/div>\n

\n

“We supply reversing hot rolling mill pinion stands and require double helical gears<\/a> at ISO 1328 grade 8 in 40CrNiMoA. Korea Ever-Power produced to our drawing with OEM marking. No axial displacement of the pinion housing has been observed since conversion from single helical \u2014 the issue that caused the original conversion specification.”<\/p>\n

Lee Dong-woo<\/strong>  |  Rolling Mill Equipment Manager, Pohang Steel Machinery  ·  Q4 2025<\/em><\/p>\n<\/div>\n

\n

“We build marine main reduction gearboxes for fishing vessels and needed double helical gears in cast steel at a competitive price with a short lead time. Korea Ever-Power quoted within 24 hours and delivered 15 working days after drawing confirmation. The OEM marking was applied to the gear web as specified. We have since placed three production orders.”<\/p>\n

Park Hyun-sik<\/strong>  |  Procurement Manager, Busan Marine Gearbox Manufacturing  ·  Q1 2026<\/em><\/p>\n<\/div>\n

\n

“We used Korea Ever-Power’s design service for a double helical gear set in a new electric motor test stand \u2014 no previous design existed. They calculated the gear geometry from our input\/output parameters, produced the drawing, and had it approved within our engineering review cycle. The prototype gears matched the drawing dimensions at incoming inspection.”<\/p>\n

Choi Ji-woo<\/strong>  |  Test Equipment Engineer, Gyeonggi Motor Testing Systems  ·  Q3 2025<\/em><\/p>\n<\/div>\n

\n

“We source double helical gears in 20CrNiMo for electric vehicle reduction units. The 15\u201318 working day mass production lead time fits our monthly production programme. Korea Ever-Power confirmed the helix angle on our drawing was within their hobbing capability before accepting the order \u2014 no surprises at delivery.”<\/p>\n

Yoon Sang-min<\/strong>  |  Component Sourcing Engineer, Seoul EV Drivetrain Co.  ·  Q2 2025<\/em><\/p>\n<\/div>\n<\/div>\n

<\/p>\n

Related Products<\/h2>\n
\n
\n
\n \"Double
\n <\/a><\/p>\n
\n

Helical Gears<\/h3>\n

Korea Ever-Power’s full range covers heavy machinery double helical gears, carburised mining gears, metallurgy soft tooth flank gears, agricultural machinery gears, and precision ground helical gears \u2014 all custom-produced to drawing.<\/p>\n

Browse Helical Gears \u2192<\/a>\n <\/div>\n<\/p><\/div>\n

\n
\n \"Forging
\n <\/a><\/p>\n
\n

Ingranaggi conici<\/h3>\n

Forged straight and spiral bevel gears in alloy steel for right-angle direction changes in heavy crane slewing drives, marine steering gear, and rolling mill auxiliary drives \u2014 the intersecting-shaft complement to double helical parallel-axis gears.<\/p>\n

Browse Bevel Gears \u2192<\/a>\n <\/div>\n<\/p><\/div>\n<\/div>\n

\n

Request a Quotation for Heavy Machinery Double Helical Gears<\/h3>\n

Send drawing with module, tooth count, helix angle, material, accuracy grade, and OEM marking requirements. Mass production 15\u201320 working days. Design and prototyping services available.<\/p>\n

Get a Quote Now<\/a>\n<\/div>\n<\/div>","protected":false},"excerpt":{"rendered":"

Korea Ever-Power heavy machinery double helical gears are manufactured in cast steel and alloy steel with quenching and tempering heat treatment, producing a soft tooth surface suited to the shock and reversing loads of heavy industrial drives. Gear accuracy grade 8\u20139 per ISO 1328. 20\u00b0 pressure angle; helix angle to customer specification. Available in all standard alloy grades from 45# carbon steel through 40CrNiMoA \u2014 see the steel cross-reference table for international equivalents. Custom material, helix angle, and dimensions to customer drawing or sample. Mass production lead time 15\u201320 working days. OEM marking available. Applications include cranes, mining equipment, rolling mills, compressors, and heavy conveying equipment.<\/p>","protected":false},"featured_media":1510,"comment_status":"closed","ping_status":"open","template":"","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":""},"product_brand":[],"product_cat":[4558],"product_tag":[],"class_list":["post-1509","product","type-product","status-publish","has-post-thumbnail","product_cat-helical-gear","pa_editor-cxm","first","instock","product-type-simple"],"_links":{"self":[{"href":"https:\/\/gearrack.top\/it\/wp-json\/wp\/v2\/product\/1509","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gearrack.top\/it\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/gearrack.top\/it\/wp-json\/wp\/v2\/types\/product"}],"replies":[{"embeddable":true,"href":"https:\/\/gearrack.top\/it\/wp-json\/wp\/v2\/comments?post=1509"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/gearrack.top\/it\/wp-json\/wp\/v2\/media\/1510"}],"wp:attachment":[{"href":"https:\/\/gearrack.top\/it\/wp-json\/wp\/v2\/media?parent=1509"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/gearrack.top\/it\/wp-json\/wp\/v2\/product_brand?post=1509"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/gearrack.top\/it\/wp-json\/wp\/v2\/product_cat?post=1509"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/gearrack.top\/it\/wp-json\/wp\/v2\/product_tag?post=1509"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}