Product Description
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Milwaukee 5/8-11 Spindle Hub Assembly with Pinion
Model Number: 14-73-0500
The Milwaukee 14-73-0500 is a genuine OEM 5/8-11 Spindle Hub Assembly with Pinion designed for the Milwaukee 2780-20 M18 FUEL 4-1/2 in. / 5 in. Angle Grinder with Paddle Switch and No-Lock (serial code F33D), the 2781-20 M18 FUEL 4-1/2 in. / 5 in. Angle Grinder with Slide Switch and Lock-On (serial code F32D), and the matching 2781-22HD kit. Identified as Figure 61 on Milwaukee service bulletin 54-38-7012, this is the complete pre-assembled spindle hub unit that includes the bevel gear, output bearing, 5/8-11 threaded spindle shaft, and lower case as a single replacement assembly with the pinion gear that engages the rotor. The spindle hub is the structural and mechanical heart of the grinder's output side, taking the rotational input from the rotor pinion at the rear of the gearcase, transferring it through the bevel gear at the platform's 3.54 to 1 reduction ratio, and delivering the 8,500 RPM rotational output to the 5/8-11 UNC threaded spindle that mounts grinding wheels, flap discs, cutting wheels, wire cups, and other 5/8 in. arbor accessories up to 5 in. (127 mm) in diameter.
Replacing the spindle hub assembly with this OEM service part restores correct gear engagement, smooth bearing rotation, accurate spindle runout, and reliable accessory mounting after wear, gear damage, bearing failure, spindle thread damage, or impact damage to the lower case. Because the 14-73-0500 ships as a comprehensive pre-assembled service kit that includes the pinion, O-ring, guard locking tang, locking spring, steel pin, and the locking tang retaining screw all bundled together, the repair eliminates the labor and tooling required to disassemble, replace, and re-shim individual gear, bearing, and guard-lock components, restoring the tool to factory specification with a single part number. This is one of the most complete spindle hub service kits Milwaukee offers, since it captures both the rotational drive components and the guard-lock mechanism in one assembly. Because Milwaukee Tool specifies replacement parts by both catalog number and serial number, always verify your tool's serial number against the official Milwaukee 2780-20 or 2781-20 service parts diagram before ordering, since Milwaukee occasionally implements running production changes that affect part compatibility within the same catalog number. The 14-73-0500 is specific to the 2780-20, 2781-20, and 2781-22HD platforms (F32D and F33D serial codes) and is NOT interchangeable with the spindle hub assemblies used on the newer M18 FUEL grinder generations such as the 2880-20, 2881-20, 2888-20, or 2889-20 (L64A, L65A, L70A serial codes), which use the different 14-73-2000 spindle hub assembly. Verify by serial number using Milwaukee's online parts lookup before ordering to confirm correct fitment.
Features
- Genuine Milwaukee OEM replacement, direct factory part for the 14-73-0500 reference
- Designed for the Milwaukee 2780-20 (F33D), 2781-20 (F32D), and 2781-22HD (F32D) M18 FUEL 4-1/2 in. / 5 in. Angle Grinders
- Comprehensive pre-assembled service kit with pinion, O-ring, bevel gear, output bearing, 5/8-11 spindle shaft, lower case, guard locking tang, locking spring, steel pin, and retaining screw
- 5/8-11 UNC threaded spindle for standard grinder accessory mounting
- 3.54 to 1 gear reduction ratio drives the platform's 8,500 RPM working speed
- Single-part replacement eliminates the need to source and assemble individual gear, bearing, and guard-lock components
- Includes the complete guard-lock mechanism, restoring proper guard rotation detents and lock function
- Manufactured to Milwaukee factory tolerances, gear geometry, and bearing fit specifications
- Direct-fit replacement, no modification required for installation
- Restores smooth gear engagement, accurate spindle runout, reliable accessory mounting, and correct guard locking after wear or damage
- Compatible with all standard 5/8 in. arbor accessories: grinding wheels, flap discs, cutting wheels, wire cups, and polishing pads up to 5 in. diameter
Specifications
- Manufacturer: Milwaukee Tool
- Part Number: 14-73-0500
- Official Description: 5/8-11 Spindle Hub Assembly with Pinion
- Component Type: Complete Pre-Assembled Spindle Hub Unit
- Spindle Size: 5/8 in. (5/8-11 UNC standard grinder thread)
- Gear Ratio: 3.54 to 1
- Output Speed: 8,500 RPM (per platform specification)
- Wheel Capacity: Up to 5 in. (127 mm) x 1/4 in. (6 mm)
- Confirmed Compatible Models: 2780-20 (F33D) M18 FUEL 4-1/2 in. / 5 in. Grinder Paddle Switch No-Lock, 2781-20 (F32D) M18 FUEL 4-1/2 in. / 5 in. Grinder Slide Switch Lock-On, 2781-22HD (F32D) Kit
- Service Bulletin Reference: 54-38-7012, Figure 61
- Quantity: Sold as a complete assembly, 1 hub per order
- Part Type: OEM Service Replacement Assembly
Includes
- (1) Milwaukee 14-73-0500 5/8-11 Spindle Hub Assembly with Pinion, complete with all sub-components listed below
- (1) Pinion gear
- (1) Bevel gear (pre-installed)
- (1) Output bearing (pre-installed)
- (1) 5/8-11 threaded spindle shaft (pre-installed)
- (1) Lower case (pre-installed)
- (1) O-Ring (Milwaukee 34-40-0180)
- (1) Steel Pin (guard lock detent)
- (1) Spring (guard lock return spring)
- (1) Guard Locking Tang (Milwaukee 44-20-0155)
- (1) M3 x 5mm Pan Head Self-Tapping T-8 Screw (Milwaukee 05-81-0020)
- Note: Gearcase Assembly (Milwaukee 14-30-1167), Electronics Kit (Milwaukee 14-20-2690), Housing Kit (Milwaukee 31-44-0895), Rotor Assembly (Milwaukee 16-07-2690), Baffle Assembly (Milwaukee 42-14-0040), and other tool components are NOT included and sold separately
- Note: Grinding wheels, flap discs, cutting wheels, wire cups, and other accessories are NOT included and sold separately
- Note: This assembly is specific to the 2780-20, 2781-20, and 2781-22HD platforms (F32D, F33D serial codes). It is NOT compatible with the newer M18 FUEL grinder generations 2880-20, 2881-20, 2888-20, or 2889-20 which use the different Milwaukee 14-73-2000 spindle hub assembly
- Note: Verify your tool's catalog number and serial number against the official Milwaukee parts diagram before ordering
