LiftMaster K12-19504 Keyed Flange Bearing — 1-Inch

The LiftMaster K12-19504 is the 1-inch keyed flange bearing identified in commercial door operator repair-parts information. It supports the specified shaft arrangement and must match the model’s bearing position, mounting and shaft dimensions. The manufacturer’s H-operator parts document lists this individual bearing separately from the K12-16607 two-bearing kit reference. Select the correct purchasing scope before ordering: a matching one-inch shaft size alone does not prove that another bearing has the right flange, keying or mounting geometry.

Compatibility — Models, Versions and Exclusions

Inspect the Shaft and Mounting Support with the Bearing

Noise, looseness or rough rotation can involve the bearing, shaft surface, alignment or mounting support. Have the technician check the complete assembly before deciding which parts to retain. A replacement bearing installed on a damaged shaft may not restore the intended fit, and a distorted support can leave the drive misaligned even after the bearing is replaced.

Locate the exact bearing position in the operator diagram and record the arrangement before disassembly. Do not enlarge a mounting opening or force a mismatched flange into place. Follow the manufacturer’s assembly, retention and lubrication guidance for the service part. Inspect related chain and shaft connections while access is available, then restore guards and complete the required door-operating checks.

Specifications and Product Identification

Before Ordering

• Record the complete operator model and bearing position.
• Match K12-19504 and the one-inch size designation.
• Inspect shaft condition, support alignment and retention hardware.
• Confirm whether the repair needs one bearing or a separately listed kit.

Package Contents and Separate Requirements

This offer identifies the K12-19504 bearing. Do not assume the quantity or contents of the separately listed two-bearing kit apply to this individual reference. A shaft, sprocket, chain, mounting support and complete operator are not promised as included. Confirm current supplied hardware and order any additional bearings or damaged drive parts separately using the correct parts diagram.

Safety Warnings — Read Before Installation or Service

• WARNING: A moving commercial door and exposed shafts and bearing supports can cause serious injury or death. Have a trained door-systems technician perform installation and service.
• Disconnect mains power and any battery backup before mechanical work or wiring. Secure the door against unexpected movement as directed by its manufacturer.
• Do not work on springs, cables or counterbalance components without appropriate training. Never bypass safety sensors or increase force to overcome binding.
• Restore guards and complete the model-specific travel, reversal and protection-device tests before returning the door to normal operation.

Related Products and Important Differences

• #50 roller chain — a separate drive component where the actual operator specifies this chain family.
• #50 master link — a separate chain component; bearing size alone does not establish chain compatibility.

Frequently Asked Questions

Is this a one-inch bearing?

Yes. The manufacturer parts description identifies the one-inch keyed flange bearing.

Does the offer include two bearings?

Do not assume that. The two-bearing kit has a separate service reference.

Can any one-inch bearing replace it?

No. The flange, keying, mounting and intended shaft arrangement must match.

Will a new bearing repair a worn shaft?

No. The shaft and support condition require separate assessment.

Need Help Confirming the Right Product?

Contact Garage-DoorParts.com before ordering. Send the full equipment model, readable part labels and photographs of the installed assembly. Include the dimensions, electrical configuration or accessory details relevant to your project so the listing can be checked against the actual installation.