WPW Series Universal Speed Worm Gearboxes-Product_0035

WK Series Worm Gear Reducer

The WK is the W-family’s standard hollow bore unit — the one that goes to size 200 with an Ø85 mm bore, covering shaft diameters that no WP-family hollow-bore unit can reach. Through-shaft input on both faces for motor positioning flexibility; FCWK variant adds IEC B5 motor flange. Smooth continuous loads; W-series dimensional footprint.

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Description

The WK Series Worm Gear Reducer — with its motor-flange variant designated FCWK — is the W family’s hollow-bore unit built on the standard W series housing geometry. The WK carries a through-shaft solid input (motor couples to either side via a standard jaw coupling) and a hollow bore output that seats directly onto the driven shaft. The FCWK replaces the through-shaft input with an IEC B5 motor flange, removing the input coupling from the drivetrain. Both variants extend to size 200 — the widest size range in the W-family hollow-bore category, covering output bore diameters from Ø20 mm at size 50 up to Ø85 mm at size 200 — and weight from 6 kg to 200 kg. For Australian conveyors, agricultural equipment, and material handling machinery designed around the W series dimensional convention, the WK/FCWK provides the shaft-mount hollow bore output within the same housing envelope that the machine was originally engineered for, with no baseplate modification required.

WK FCWK shaft direction and dimensional diagram

Technical Specifications — WK Series (and FCWK Variant)

WK — Through-Shaft Input

Solid input shaft extends from both housing faces — motor couples to either side via jaw coupling. Unused side capped with blanking cap. Hollow bore output. Sizes 50–200, foot-mounted.

FCWK — IEC Flange Input

IEC B5 motor flange replaces through-shaft input. No input coupling, no coupling guard. Same hollow bore output. Motor bolts directly; fixes to one face. Sizes 50–200, foot-mounted.

Size Ratio A (mm) B (mm) AC (mm) H (mm) HL (mm) Input HS (mm) Output Bore S (mm) Weight (kg)
50 1/10–1/60 175 107 115 150 35 30 Ø20 6
60 1/10–1/60 195 117 126 177 42 40 Ø25 8.5
70 1/10–1/60 234 131 155 215 55 40 Ø30 12.5
80 1/10–1/60 264 144 174 250 65 50 Ø35 20
100 1/10–1/60 322 175 224 310 80 50 Ø40 33
120 1/10–1/60 385 200 264 370 95 65 Ø45 50
135 1/10–1/60 435 212 304 425 105 75 Ø60 77
155 1/10–1/60 494 312 330 461 103 85 Ø70 100
175 1/10–1/60 548 334 370 521 123 85 Ø80 140
200 1/10–1/60 688 346 420 575 130 95 Ø85 200

Sizes 50–200
Ratio 10:1–60:1
W-Series Housing
Hollow Bore Ø20–85mm
WK: Through-Shaft Input
FCWK: IEC Flange Input

WK in the W-Family Bore Depth Hierarchy

The W family offers three hollow-bore depth grades at each size number. Understanding where the WK sits determines whether it is the right specification or whether the WKA (deeper bore, next article) is the correct selection:

Variant HL at Size 100 (mm) Shock Tolerance Best Application
WK / FCWK 80 mm Moderate (SF ≤ 1.5) Smooth continuous loads; legacy W series shaft-mount retrofits
WA 100 mm Moderate (SF ≤ 1.75) Standard shaft-mount applications; WP-family dimensional convention
WKA 150 mm High (SF ≤ 2.5) Shock loads, auger stone strikes, screw conveyor axial thrust; W series footprint

Selection guidance: The WK (HL = 80 mm at size 100) is the correct choice when the driven shaft load is smooth and continuous with no significant shock, and the W series dimensional convention is required — particularly when replacing an existing W series solid-shaft unit with a shaft-mount hollow-bore unit on the same machine without baseplate modification. For any shock loads, specify the WKA.

WK Series FCWK Worm Gear Reducer — Hollow Bore Output

WK/FCWK Key Advantages

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Size 200 — Largest W-Family Hollow Bore

The WK extends to size 200 with a Ø85 mm output bore and 200 kg unit weight — the largest hollow-bore specification available in the W family. No WP-series hollow-bore unit reaches this frame. For large conveyor head shafts and bulk handling equipment built around the W series convention, the WK200 is the only available hollow-bore option at this scale.

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WK: Motor on Either Side

The WK through-shaft input allows the motor coupling to be placed on either side of the housing. In legacy W series equipment where structural elements constrain motor position, this flexibility eliminates the need to redesign the motor mounting bracket when retrofitting the shaft-mount configuration.

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W-Series Footprint — No Baseplate Change

WK housing dimensions match the W series convention — A, B, H, and foot pad bolt pattern are identical to the W series baseline. When replacing a W series solid-shaft unit with a WK hollow-bore unit on the same machine, the baseplate, motor base, and coupling guard are the only components that change. The structural machine bay requires no modification.

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Self-Locking at ≥ 30:1

Static self-locking at 30:1 and above holds the output bore stationary on power-off without a brake. In foot-mounted configuration with the shaft-mount bore engaged, the locking torque acts directly on the driven shaft through the bore connection. For gravity-loaded conveyors and gate actuators, this eliminates a separate braking device.

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FCWK: Motor-Direct, Zero Input Coupling

The FCWK IEC B5 flange eliminates the input coupling and coupling guard — any IEC B5 motor of the correct frame bolts directly to the flange face. Motor shaft and worm shaft are concentric within 0.05 mm TIR. In OEM production, this saves 45–60 minutes of motor base fabrication and coupling alignment time per unit.

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No Output Coupling — Shaft-Mount Direct

The hollow bore output eliminates the output coupling, coupling guard, and output alignment procedure. The driven shaft becomes the mounting reference — the WK/FCWK slides directly onto it and is retained by key and locking element. In wet-area and food-grade environments, this removes one coupling gap and one rotating guard surface from compliance obligations.

Application Environments — WK for Legacy Retrofit, FCWK for New Motor-Direct Builds

  • 🔄 Legacy W Series Machine Shaft-Mount Retrofit (WK)
    When an existing W series solid-shaft machine is upgraded to shaft-mount drive (eliminating the output coupling as part of a maintenance simplification programme), a WK replaces the W series unit: same baseplate, same motor, same motor coupling — only the output connection changes. Sizes 50–200 match the full W series range.
  • ⛓️ Conveyor Head Shaft Drives — Large Shaft Diameters (WK/FCWK)
    Large conveyor head shafts at sizes 155–200 (Ø70–85 mm bore) in Australian bulk handling and mining are exclusively served by the WK/FCWK — no WP-series hollow-bore unit reaches these bore diameters. FCWK configuration at this scale eliminates the input coupling, which is a significant fretting and maintenance liability on the large-diameter input shafts of Class 3 and 4 conveyors.
  • 📦 OEM Packaging Machines — Motor-Direct Shaft-Mount (FCWK)
    FCWK size 50–80 for packaging conveyor and metering drives where both the motor coupling (input) and the output coupling are eliminated. W series dimensional convention is preserved for OEM builders standardised on W series frame dimensions. No baseplate redesign required between motor-coupled W series and FCWK production generations.
  • 🌾 Agricultural Implement Electric Conversion (FCWK)
    Tractor PTO-driven implements converted to electric motor drive use FCWK size 80–120 where the motor must flange-mount directly to the reducer and the bore seats on the existing implement shaft. The IEC B5 flange accommodates any standard electric motor; the W series housing fits the implement’s existing frame clearance envelope that was originally designed around the W series reducer. For PTO shaft sizing reference, see our PTO shaft technical resources.
  • 💧 Water Treatment and Irrigation Infrastructure (WK)
    Gate actuators and paddle mixers in Australian irrigation infrastructure built around W series dimensional conventions use WK for shaft-mount output — the through-shaft input allows motor positioning to clear headstock structural members on either side. The sealed housing with hollow bore output presents no coupling gap for water ingress in flood-prone installations.

Drive Accessories and Input Integration

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WK: Motor + Jaw Coupling

Standard jaw coupling to either WK input stub. Couple to the motor-access side; cap the other with the blanking cap and lip seal. Inspect both seals — the capped stub and the active input shaft seal — at every oil change interval.

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FCWK: IEC B5 Motor — Frame Check Critical

Verify motor IEC frame against FCWK flange dimensions: Z×L foot bolt, BD/BE cross dimensions. Motor shaft length must not exceed T×V bore depth. Record the motor IEC frame on the plant maintenance schedule for remote-site replacement planning.

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Output Bore Locking Element

Set screw for smooth continuous loads (WK HL = 80 mm provides moderate engagement). For any reversing or cyclic loads, specify a shrink disc — the WK’s shorter bore depth concentrates shock torque over a smaller key face area than the WKA, making shrink disc locking more important at the margin.

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Torque Arm

In shaft-mount configuration, torque arm anchors housing against reaction torque. For FCWK, torque arm load includes motor weight moment — size accordingly. WK size 175 and 200 require heavy-duty torque arm with dual rubber bushes given the 140–200 kg combined reducer weight alone.

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Oil and Breather

ISO VG 220 mineral gear oil standard fill. For sizes 175 and 200, verify fill level for the installed orientation — non-standard shaft-mount orientations at large frame sizes create significant oil redistribution. A pressure-equalising breather prevents seal weeping under positive housing pressure at high duty cycles.

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WK: Blanking Cap — Dusty Environments

The WK unused input stub blanking cap is a critical seal in Australian agricultural and mining environments. Fit a secondary labyrinth dust cap over the standard blanking cap in dusty conditions. Inspect and replace the lip seal at every oil change — failed blanking cap seals are the leading cause of premature worm wheel wear in W-family units across Australian field service.

Maintenance Schedule — WK/FCWK

Interval Task WK/FCWK Note
First 500 hours Oil flush; bore fretting inspection; blanking cap check (WK) WK shorter HL means earlier fretting indicator — rust-brown powder at bore face within first 500 hours signals inadequate locking force; upgrade to shrink disc immediately
Every 2,500 hours Oil change; all seals; locking element re-torque WK: replace blanking cap lip seal proactively — Australian dust and moisture conditions accelerate lip hardening faster than clean-environment service intervals suggest
Every 5,000 hours Remove bore from shaft; bore and shaft contact inspection WK HL = 80 mm means bore fretting progresses to bore widening faster than WKA at same torque — confirm bore diameter within 0.03 mm of original spec; replace housing if bore is out of round
FCWK motor replacement Verify IEC frame and shaft length before ordering Log motor frame on maintenance schedule at installation — at large sizes (155–200), motor frame errors cause multi-day delays on remote Australian sites
WK FCWK worm reducer dimensional reference

For WK/FCWK size 175 and 200 procurement planning, dimensional cross-referencing with legacy W series equipment, bore locking element selection, and torque arm sizing at large frame weights, the engineering team at our worm gearbox technical portal provides application-specific support. Contact us via the technical enquiry page with driven shaft diameter, load torque, and ambient temperature for a confirmed selection recommendation.

Frequently Asked Questions — WK Series (FCWK)

1. When should I specify WK instead of WKA?
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Specify the WK when the driven load is smooth and continuous with a service factor of 1.5 or below, and the driven shaft diameter is matched to the WK bore S dimension. The WK’s shorter HL (80 mm at size 100) is sufficient for these conditions and provides a more economical specification than the WKA (150 mm at size 100). Specify the WKA when shock loads are present, the driven shaft generates axial thrust, or the application service factor exceeds 1.5 — the additional bore depth in the WKA is the engineering argument for each of these conditions.
2. Why does the WK extend to size 200 when the WKA does not?
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The WK and WKA both extend to size 200 — both are available at the full W series size range. At size 200, the WK bore (Ø85 mm, HL = 130 mm) and WKA bore (Ø85 mm, HL = 290 mm) provide different bore depth options for the same bore diameter. The WK size 200 suits large smooth-load conveyor head shaft applications; the WKA size 200 suits the same shaft diameters under heavy shock or sustained axial thrust. Neither WP-series hollow-bore unit offers a bore diameter above 80 mm (WPKS/WPDKS size 175), making both WK200 and WKA200 the exclusive specifications for shaft diameters of 85 mm within the worm gear reducer category.
3. Is the FCWK dimensionally compatible with the FCWD at the same size number?
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No — the FCWK has a hollow bore output while the FCWD has a solid shaft output. They share the same IEC B5 input flange standard at the same size number (LZ, LB, Q, Z×L match), but the output section is different in both geometry and the presence of a bore versus a shaft stub. They are not drop-in substitutes for each other on the output side. An FCWK can be used in place of an FCWD where a shaft-mount output is preferred over a solid-shaft-with-coupling output — but the output connection to the machine must be redesigned to accept the bore rather than a coupling bored to the FCWD shaft diameter.
4. What are the oil orientation requirements for the WK size 200 in a non-standard installation?
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The standard oil fill for the WK series applies to the horizontal worm shaft, horizontal bore axis orientation. At size 200, the housing mass and oil volume (typically 3.5–4.5 litres) means that non-standard orientations — bore axis vertical, or bore axis horizontal with motor shaft vertical — require specific fill levels that differ substantially from the horizontal reference. For shaft-mounted WK200 units in non-standard orientations, submit your installed orientation to the technical enquiry team and request the orientation-specific fill level before commissioning. Incorrect oil level at size 200 in a non-standard orientation is the most common cause of premature worm gear failure on large W-family units in the first 1,000 hours of service.
5. What is the stock and lead time for WK/FCWK at sizes 175 and 200 in Australia?
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WK/FCWK sizes 50 through 155 are held in stock with 3–5 business day despatch. Sizes 175 and 200 are manufactured to order with 6–8 week lead times — the casting, machining, and assembly requirements for a 140–200 kg unit justify early project procurement. For project scheduling, initiate procurement at least 10 weeks before the required installation date. Contact the technical enquiry team with your project timeline and quantity to confirm production scheduling and freight planning for large frame deliveries.

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