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Carbon steel shaft coupling, 4-1/2 inch length, keyed bores

Dayton

Dayton 3ZN51 Rigid Shaft Coupling 4-1/2 in

SKU CH-B27V-S74QZ MPN 3ZN51

Connects two 1 3/8 in round keyed shafts with a 4 1/2 in carbon steel one-piece coupling rated for 1,500 in-lb torque at 1,800 RPM

  • Product typeDrain Components
  • Transmits up to 1,500 in-lb torque for heavy-duty drives
  • Handles 1,800 RPM maximum speed in continuous operation
  • One-piece carbon-steel body eliminates joint movement
  • Round keyed bores with 5/16 in keyways ensure positive lock
  • 4-1/2 in overall length fits standard shaft spacing

Rigid Shaft Coupling for Power Transmission

This rigid shaft coupling joins two rotating shafts with identical 1 3/8 in round keyed bores. Its one-piece carbon steel construction transmits torque without flexibility or misalignment compensation. The 4-1/2 in overall length suits fixed shaft spacing in industrial machinery. Maximum rated speed is 1,800 RPM and maximum torque capacity is 1,500 in-lb.

For Inline Shaft Connections Only

This coupling suits maintenance teams replacing a worn rigid coupling on equipment with perfectly aligned shafts and matching 1 3/8 in keyed bores. It will not work for applications that require angular or parallel misalignment accommodation, vibration damping, or different bore diameters on each shaft. Buyers needing flexible or tapered bore couplings should look elsewhere.

1 3/8 in Identical Keyed Bores Decide Fit

Both bores measure 1 3/8 in with 5/16 in keyway width and 5/32 in keyway depth, so the shafts must match these dimensions exactly. The 2 3/8 in outside diameter and 2.38 in clearance diameter define the space envelope around the connection. Verify shaft size, keyway geometry, and alignment before ordering.

How it compares

Measured against everything we stock in Drain Stoppers, Strainers & Traps, at today’s prices. Recalculated every night.

Price $42.99
Pricier than about 58% of the 4,240 comparable items (median $31.99).

Specifications

Product
Brand nameDayton
Model name3ZN51
Product typeDrain Components

Questions about this item

What shaft diameter must I already have for the 1 3/8 in bore to fit?

Both shafts must measure exactly 1 3/8 in outer diameter to match the coupling's round keyed bores.

Will the 1 800 RPM limit and 1 500 in-lb torque rating suit an older motor running at lower speeds?

Yes, the coupling handles up to 1 800 RPM and 1 500 in-lb, so slower legacy motors stay well within its ratings.

How do I confirm the coupling is seated correctly after tightening the set screws?

Verify the 4 1/2 in overall length spans the shafts evenly and that no wobble appears when the assembly rotates by hand.

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