Product Overview
The 516718-8 Armature Rotor is a precision-engineered direct-fit replacement for the 255mm miter saws built on the LS1040 / LS1045 platform. This armature is the heart of the motor – converting electrical energy into the rotational force that drives the blade through hardwood, softwood, and engineered materials with precision and consistency.[reference:4]
Designed for professional repair technicians and equipment maintenance specialists, this armature restores factory-spec performance to tools exhibiting sluggish operation, loss of cutting power under load, or complete motor failure. The 2,600 RPM no-load speed delivers the cutting efficiency required for clean, accurate crosscuts in demanding workshop applications.
Built with robust copper windings and a durable commutator, this armature is engineered to withstand the rigors of continuous cutting operations. The precision-balanced rotor ensures smooth operation with minimal vibration – reducing wear on bearings and extending the service life of the complete tool.[reference:5]
This armature is referenced under OEM part number 516718-8 and is the direct replacement for the original equipment armature in LS1040, LS1040N, LS1045, LH1040, and LH1040F miter saws.[reference:6][reference:7]
💡 Pro Tip – Pre-Installation Diagnostic: Before replacing the armature, perform a visual inspection and continuity test. Remove the armature from the motor housing and inspect the commutator surface – if it’s heavily grooved, scored, or shows signs of arcing, the armature has failed. Use a multimeter to test for shorts between commutator segments (all segments should show similar resistance, typically 0.5–2.0 ohms) and between any segment and the shaft (infinite resistance = no short to ground). Also inspect the field coil (stator) for continuity – if the field coil is damaged, armature replacement alone won’t resolve the issue. Always disconnect the tool from mains power before beginning any disassembly.
Diagnostic & Fitment – When to Replace
Specification Comparison
| Specification | Worn / Generic Aftermarket | FixPartHub Precision Replacement ✅ |
|---|---|---|
| No-Load Speed | Inconsistent – below 2,600 RPM | 2,600 RPM – OEM-spec |
| Winding Quality | Substandard copper – high resistance | OEM-spec copper windings – optimal conductivity |
| Rotor Balance | Unbalanced – vibration & bearing wear | Precision-balanced – smooth operation |
| Commutator Durability | Soft copper – rapid grooving | Robust commutator – extended service life |
| Compatibility | Vague or incorrect fitment claims | LS1040 / LS1040N / LS1045 / LH1040 / LH1040F – direct-fit guaranteed |
Teardown & Replacement Workflow
Compatibility – Cross-Reference & OEM Part Numbers
Diagnostic Q&A
❓ Q: My miter saw runs slowly and lacks cutting power – is this definitely an armature problem?
A: Not always. First, check the carbon brushes – if they’re worn below 5mm or show signs of glazing, replace them. Check the field coil (stator) for continuity with a multimeter. If the brushes and field coil check out, the armature is the likely culprit. Worn armature windings or a damaged commutator will cause loss of power and reduced cutting efficiency – requiring replacement of the 516718-8 armature.
❓ Q: What models are compatible with the 516718-8 armature?
A: This armature is compatible with LS1040, LS1040N, LS1045, LH1040, and LH1040F 255mm miter saws.[reference:8][reference:9]Always verify your tool’s model number against the compatibility list before ordering.
❓ Q: How do I test if the armature is faulty with a multimeter?
A: Use a multimeter in resistance mode. Test between adjacent commutator segments – they should all show similar resistance (typically 0.5–2.0 ohms). A short (0 ohms) between any two segments indicates a shorted winding. An open circuit (infinite resistance) indicates a broken winding. Also test between any commutator segment and the armature shaft – there should be infinite resistance (no short to ground). If the armature fails any of these tests, replacement is required.
❓ Q: What is the weight of the 516718-8 armature?
A: The 516718-8 armature weighs approximately 1,200g (1.2 kg) – a substantial, heavy-duty rotor designed for professional-grade miter saw applications.[reference:10]
Safety Notes
- 🔴 Always disconnect the tool from mains power before beginning any disassembly or armature replacement procedure.
- ⚡ Allow the motor to cool completely before handling internal components – motors can reach high temperatures during cutting operations.
- 🔧 Use correct torque values – housing screws and bearing retainers typically require 1.5–2.0 Nm (13–18 in-lbs). Over-torquing can strip threads or damage the housing.
- 🧤 Wear ESD-safe gloves when handling the armature to prevent static discharge damage to sensitive components.
- 📐 Verify commutator alignment before final assembly – the armature should spin freely with no binding or grinding feel.
- ✅ Perform a no-load test before reinstalling the blade and guard – verify smooth operation at full speed with minimal sparking.
A: Common symptoms include loss of cutting power under load, reduced blade speed, excessive sparking through the motor vents, a burning smell during operation, or complete failure to start. A multimeter test can confirm – check for shorts between commutator segments or shorts to ground (the armature shaft). If the armature fails any of these tests, replacement with a 516718-8 armature is required.
A: This armature is compatible with LS1040, LS1040N, LS1045, LH1040, and LH1040F 255mm miter saws.Always verify your tool’s model number against the compatibility list before ordering.
A: The armature delivers 2,600 RPM no-load speed – the OEM specification for the LS1040 series miter saws.
