Industrial Double Helical Gears – Alloy Steel, OD to 1370mm

Industrial double helical gears — the herringbone gear form — are among the most demanding products in gear manufacturing. Two helical tooth sets of opposite hand cut side by side on a common blank produce a gear that transmits high power with smooth, low-vibration tooth engagement, zero net axial thrust on the shaft bearings, and greater load-sharing capacity per unit of centre distance than any other external parallel-shaft gear type. These properties come at a cost in manufacturing complexity: double helical gears require more production steps than single helical or spur gears of equivalent size, and hence cost more — but the performance difference justifies the premium in demanding industrial drives.

Korea Ever-Power produces industrial double helical gears up to 1,370 mm (54 inches) outer diameter, 250 mm (10 inches) full face width, and 30° helix angle, with a wide selection of pitch cutters. Material, diameter, capacity, and all geometric parameters are customisable to the customer's drawing. Drawing files in PRO/E, AutoCAD, SolidWorks, and UG are accepted.

Custom Production to Drawing or Sample

All products made to customer artwork or sample — free samples available for simple and low-value configurations. Drawing formats accepted: PRO/E, AutoCAD, SolidWorks, UG. Material, module, diameter, face width, helix angle, and bore all specified per drawing.

Sample Inspection Reports

Official inspection reports submitted with every sample delivery: material report confirming alloy grade, mechanical property report confirming tensile and hardness, and dimensional report confirming all geometric parameters against the drawing. Third-party inspection report from an accredited body available on request.

Quality Guarantee

One-year quality guarantee from the date the customer receives the products. In the event of a quality issue, the complaint procedure activates immediately and a resolution and compensation scheme is implemented within 48 hours.

Storage Service

Buffer stock storage available for customers with continuing supply programmes. Gears stored are inspected and documented before storage and re-inspected before each shipment release.

Cranes

Industrial crane hoisting and slewing gearboxes up to the maximum 1,370 mm diameter. Double helical gears eliminate axial thrust from the hoisting gear stage and reduce gear-generated vibration and noise transmitted to the crane structure and cab.

Fluid Pumps

Large fluid pump gearboxes for water supply, wastewater, and industrial fluid handling. Thrust-free operation eliminates gear axial thrust from the pump shaft seal loading — a significant contributor to seal wear and leakage in conventional single helical pump drives.

Naval Propulsion

Power transmission to propulsion screws in military ships for quieter and lower-vibration operation than conventional spur or single helical gearboxes. Double helical propulsion gears in large naval vessels reach the maximum diameter range — the 1,370 mm capacity accommodates the main reduction gear wheel in frigate and destroyer class propulsion systems.

Industrial Compressors

Speed increaser and reduction gearboxes in large industrial gas compressors, where the herringbone tooth form reduces the vibration transmitted to compressor pipework and foundations compared with spur or single helical gearboxes at the same power level.

General Industrial Power Transmission

Heavy conveyors, extruders, mixers, and general industrial reduction gearboxes in the large OD range where the power density advantage of the double helical form — higher torque per unit centre distance — justifies the higher manufacturing cost compared with equivalent spur gears.

Wholesale and OEM Export

Industrial double helical gears manufactured for export OEM programmes in Europe, Southeast Asia, North America, the Middle East, and East Asia. Competitive wholesale pricing at volume, with full inspection documentation and quality guarantee for international OEM supply chains.

What is the maximum double helical gear size Korea Ever-Power can produce?

The maximum external double helical gear is 1,370 mm (54 inches) outer diameter with a full face width of 250 mm (10 inches) at up to 30° helix angle. This capacity covers the majority of industrial double helical gear applications including large crane drives, compressor gearboxes, and naval propulsion main reduction gears. For gear sizes above this limit, contact our team — we can assess whether the specific configuration can be produced or can identify appropriate sourcing alternatives.

Can Korea Ever-Power produce double helical gears from a sample rather than a drawing?

Yes — production from a sample (reverse engineering) is available. Send the sample gear and Korea Ever-Power will measure the outer diameter, tooth count, module, helix angle, hand of helix, pressure angle, bore, hub dimensions, and groove width, and prepare a production drawing for your approval before cutting begins. For large industrial double helical gears where shipping the full sample is impractical, we can work from a detailed dimensional measurement report prepared by the customer's engineering team, with key measurements confirmed by photographs.

What inspection reports are available with sample and production deliveries?

Sample deliveries include official inspection reports covering: material report (chemical composition confirming the alloy grade), mechanical property report (tensile strength, yield strength, elongation, hardness), and dimensional report (all gear parameters against the drawing dimensions). Third-party inspection from a recognised accredited body is available on request for customers whose quality systems require independent verification. For production deliveries, the same report format is available on request at the order stage.

What is the quality guarantee on industrial double helical gears?

Korea Ever-Power provides a one-year quality guarantee from the date the customer receives the products. If a quality issue arises during the guarantee period, the customer complaint procedure activates immediately upon notification and a resolution and compensation scheme is implemented within 48 hours. This guarantee covers manufacturing defects in material, geometry, and surface condition identifiable against the agreed drawing specification and inspection reports.

Is wholesale service available for distributors and trading companies?

Yes — Korea Ever-Power offers wholesale service for distributors and trading companies purchasing for resale or for consolidation into industrial equipment programmes. Competitive pricing at volume is available; contact our team with annual volume estimates and the specific gear configurations required. The same quality documentation and guarantee terms apply to wholesale orders as to direct OEM orders. Contact us to discuss wholesale pricing and terms.

"We required 1,100 mm OD double helical gears for a large industrial crane hoisting gearbox. Korea Ever-Power confirmed the size was within their 1,370 mm capacity, produced from our AutoCAD drawing with the material and mechanical property reports required by our quality system. The dimensional report confirmed all tooth parameters within our drawing tolerance."

Kim Hyeon-joo  |  Gearbox Procurement Manager, Incheon Heavy Lifting Equipment  ·  Q1 2026

"We supply water treatment pumping station gearboxes and used Korea Ever-Power's industrial double helical gears to replace a failed single helical stage. Seal life at the pump shaft improved after eliminating gear-driven axial load. Sample inspection reports met our incoming QA requirement without supplemental documentation."

Park Jae-won  |  Pump Systems Engineer, Seoul Water Treatment Engineering  ·  Q4 2025

"We manufacture compressor speed increaser gearboxes and needed 30° helix angle double helical gears at 850 mm OD. Korea Ever-Power confirmed the configuration was within their capacity (1,370 mm OD limit, 30° max helix angle), produced from our SolidWorks drawing with third-party dimensional inspection. Storage service allows us to hold 4 gear sets in China as a maintenance spare buffer."

Lee Byeong-jun  |  Compressor Gearbox Design Lead, Daejeon Industrial Gas Systems  ·  Q2 2026

"We import industrial double helical gears from Korea Ever-Power for wholesale distribution to European machinery rebuilders. The one-year guarantee and the third-party inspection reports are the two documentation items our European customers always require at incoming inspection. Both are available from Ever-Power as standard — no special requests needed."

Choi Bo-ram  |  Import Trading Manager, Busan Industrial Components Export  ·  Q3 2025

"We needed free samples of two double helical gear configurations for a prototype naval auxiliary drive before committing to production tooling. Korea Ever-Power provided the samples with the full inspection report set. Sample dimensions matched the drawing at our incoming CMM check. Production order placed for 12 sets immediately after prototype approval."

Ryu Min-jun  |  Naval Systems Component Engineer, Gyeongnam Defence Equipment Co.  ·  Q1 2025