Worm and Wheel – High Precision Brass, M3-M12, 20:1-300:1

Worm and wheel — also called worm gear transmission — is a gear pair in which a helical screw-form worm meshes with a mating worm wheel to transmit motion and power between two shafts whose axes are perpendicular and non-intersecting. The standard shaft angle is 90°. The worm resembles a bolt externally; the worm wheel resembles a helical spur gear. What makes the worm-and-wheel pair unique is the tooth contact geometry: the worm wheel tooth face is curved in the axial direction to partially envelop the worm thread, so the mating surfaces meet in line contact rather than the point contact that occurs in crossed-helical (skew) gears. This conformal contact dramatically increases the load capacity of the pair and is the geometric foundation of Korea Ever-Power's high-precision brass worm and wheel sets.

Korea Ever-Power supplies custom special high-precision worm and wheel sets for transmission — manufactured in brass, C45 steel, stainless steel, copper, POM, aluminium, and alloy steel. Module M3, M4, M5, M8, M12, and custom. Payment before shipment; T/T, L/C. Sample fee refunded on bulk order. Reverse engineering from damaged gear accepted. All metric sizes available.

① Large Transmission Ratio — Compact

Single-stage ratios of 20:1 to 300:1 in a right-angle package smaller than an equivalent planetary or spur gear multi-stage train. The ratio i = Z_wheel / n_starts (worm wheel teeth / worm thread starts). More compact than crossed-shaft helical gear mechanisms at the same ratio — ideal for applications where both high ratio and small footprint are required simultaneously.

② Line Contact — High Bearing Capacity

The enveloping tooth geometry produces line contact between the meshing surfaces — the worm wheel's concave tooth face wraps around the worm thread, distributing the contact load across a line rather than a point. This conformal contact gives worm-and-wheel transmission significantly higher bearing capacity than crossed-helical gears at the same module, and is the geometric explanation for the high torque density achievable in compact worm reducers.

③ Multi-Tooth Meshing — Smooth and Quiet

Worm drive is equivalent to a helical gear drive — it is a multi-tooth meshing drive where several worm wheel teeth engage the worm thread simultaneously at any instant. This simultaneous multi-tooth contact averages out individual tooth errors, reduces the transmission error at the mesh frequency, and produces smooth, low-vibration, low-noise operation — quieter than equivalent spur or even helical gear pairs at the same power and ratio.

④ Self-Locking — Safety Protection

When the worm lead angle is smaller than the equivalent friction angle between the meshing surfaces, the transmission is self-locking: the worm can drive the wheel, but the wheel cannot back-drive the worm. This reverse self-locking property provides built-in safety protection in heavy machinery lifting drives — if the motor fails or power is lost, the load cannot lower the worm, preventing uncontrolled descent without a separate brake.

⑤ Lower Efficiency — Design Consideration

The high relative sliding velocity between the worm thread and worm wheel tooth produces significant friction losses — efficiency ranges from 40–50% at low lead angles (self-locking range) to 80–90% at high lead angles (multi-start worms). The high sliding velocity also causes accelerated tooth surface wear and heat generation, requiring good-quality lubricant with anti-wear and anti-scuffing additives, and adequate oil cooling in high-duty-cycle applications.

⑥ Large Axial Worm Force

The worm transmits torque through an axial thrust force on the worm shaft, which is reacted by the worm shaft bearings. The axial force F_a = 2T / d_worm, where T is the worm shaft torque and d_worm is the worm pitch diameter. For high-torque worm drives, the worm shaft axial bearing selection is critical — typically angular contact or tapered roller bearings arranged in pairs to handle both the axial and radial loads on the worm shaft simultaneously.

Cast Tin Bronze (GB: ZCuSn10P1)

The standard high-duty worm wheel material. Excellent anti-friction properties, excellent anti-scuffing (galling) resistance, and good conformability — the bronze yields slightly under contact stress, improving the actual contact area progressively during run-in. Price is higher than aluminium bronze due to the tin content. Slightly lower ultimate strength than aluminium bronze. Best for: all high-duty, continuous-operation worm drives where long service life is the primary requirement.

Aluminium Iron Bronze (GB: ZCuAl10Fe3)

Higher ultimate tensile strength than tin bronze, lower cost, good wear resistance. Slightly inferior anti-friction and anti-scuffing properties compared with tin bronze — requires better lubrication conditions and lower sliding velocity to achieve equivalent service life. Best for: medium-duty worm drives where cost is a consideration and the sliding speed is moderate (≤ 5 m/s).

Cast Iron (Grey / Ductile)

Grey cast iron: adequate for low-speed, non-critical worm drives with sliding velocity ≤ 1 m/s. Ductile (nodular) cast iron: better toughness, suitable for low-speed medium-duty. Aging treatment required for cast iron worm wheels to relieve residual casting stress and prevent dimensional distortion in service. Best for: open drives, low-speed index drives, and cost-sensitive non-critical applications.

Brass (for Light Duty)

Brass worm wheels (see Korea Ever-Power's dedicated Brass Worm Wheel product) are used for light-duty, low-sliding-velocity worm drives — consumer electronics, instruments, and light mechanisms. Brass machines easily to fine tolerances at small modules, enables the combination shaft-and-wheel miniature worm sets used in precision instruments, and is corrosion-resistant. Not suitable for high sliding speeds or heavy loads where bronze is required.

Industrial Worm Gear Reducers

Tin bronze worm wheels M5–M12 in industrial worm gearbox reducers for conveyor drives, agitator drives, packaging machinery, and material handling equipment. The right-angle output and high single-stage ratio make the worm gearbox the standard compact right-angle reducer for industrial drives requiring 20:1 to 60:1 in one stage.

Security Gates and Lifting Drives

Self-locking worm and wheel sets in security shutter drives, rolling gate actuators, lifting platform drives, and vehicle barrier mechanisms. The self-locking property holds the gate or barrier in position without motor power and prevents back-driving if power is cut — a required safety feature in security and lifting applications.

Automatic Control Machines

High-precision worm and wheel sets in CNC rotary table drives, indexing heads, and robotic wrist joint drives where the right-angle output and high ratio are required in a compact, backlash-controlled assembly. Korea Ever-Power's DIN 6–7 worm and wheel sets provide the accuracy needed for positioning and indexing applications.

Solar Energy Tracking

Alloy steel worm and wheel sets in solar tracker azimuth and elevation drives. The worm gear's self-locking property holds the solar panel at the correct angle without motor power between tracking steps, reducing energy consumption and extending motor life in solar tracker drives that run for 25+ years in outdoor environments.

Machine Tools

Precision worm and wheel sets DIN 6–7 in lathe cross-slide drives, milling machine table feeds, and grinding machine wheel dresser drives. Machine tool worm drives require fine pitch control (low backlash), smooth low-speed motion (no stick-slip), and adequate rigidity — all achievable with Korea Ever-Power's ground worm thread and precision-hobbed bronze worm wheel sets.

High-Speed Rail and Aviation

Alloy steel worm and wheel sets in aircraft flap actuator drives, rail switch machine drives, and aircraft ground support equipment steering drives. These applications require full material traceability, precision tooth grinding, and independent inspection confirmation — all supplied by Korea Ever-Power with each batch delivery.

Can Korea Ever-Power accept payment after shipment?

No — Korea Ever-Power only accepts payment before shipment. Standard payment terms are T/T or L/C. The sample fee and freight are paid by the customer; after the sample is confirmed, the sample fee is refunded when the bulk order is placed. This payment structure ensures both parties' commitments are clear before production and shipment begin.

Can Korea Ever-Power manufacture worm and wheel sets not listed on the website?

Yes — all standard and custom worm and wheel sets are available with the same excellent delivery options. We have tooling to manufacture any metric module. For non-standard configurations (unusual ratios, non-standard centre distances, or special materials), send the drawing or specification and Korea Ever-Power will confirm feasibility and lead time. Reverse engineering from a damaged worm and wheel set is also available.

How do I get the lowest price on worm and wheel sets?

Increasing order quantity reduces the unit price — the more parts ordered, the lower the price. Material selection also significantly affects cost: cast iron worm wheels are the least expensive; aluminium iron bronze is moderate; tin bronze is higher due to tin content; stainless steel is the highest. Send the specification and target quantity and Korea Ever-Power will provide a tiered price schedule. Contact our team to begin.

"We manufacture industrial conveyor drive worm gearboxes and source tin bronze worm and wheel sets M8 from Korea Ever-Power. The worm thread grinding and worm wheel hobbing quality produced confirmed line contact across 85% of the face width at our incoming contact pattern check. No scuffing failures in 14 months of continuous operation at 3 m/s sliding velocity. Lead time 24 business days bulk — within the 25-day commitment."

Kim Jae-hyeon  |  Worm Gearbox Design Engineer, Incheon Industrial Drive Systems Co.  ·  Q1 2026

"We build solar tracker azimuth drives and specified alloy steel worm and wheel sets with self-locking lead angle from Korea Ever-Power. Self-locking confirmed at our test bench: applied 120% rated torque to the wheel shaft — zero back-drive rotation recorded. Panel position holds without motor power. 30 tracker units installed and operating for 18 months without worm gear maintenance."

Lee Seong-min  |  Solar Tracker Actuator Engineer, Gyeonggi Renewable Energy Systems Co.  ·  Q4 2025

"We needed a non-standard worm and wheel set — M5, 75:1 ratio (3-start worm, 225-tooth wheel), stainless steel worm with POM wheel for a food processing application requiring FDA-compliant materials. Korea Ever-Power confirmed feasibility, produced a sample in 22 business days, and confirmed mesh pattern and backlash before bulk production. No material issues at FDA inspection."

Park Min-cheol  |  Food Processing Machine Engineer, Busan Food Machinery Co.  ·  Q2 2026