71606 H.B. Smith 1-1/2" Cast Iron Split Lock Nut
OEM replacement cast iron split lock nut for H.B. Smith Mills 650 series boilers.
This rugged 1-1/2" nut secures and aligns boiler sections, providing a tight, leak-free fit under high heat and pressure conditions.
✅ Key Features
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✅ Durable cast iron construction built to withstand boiler temperatures and pressures
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✅ 1-1/2" split design for quick installation and removal
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✅ Designed specifically for Mills 650 boiler assemblies
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✅ Maintains boiler section alignment and prevents leaks
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✅ OEM-quality replacement for reliable, long-term performance
📊 Specifications
| Parameter | Detail |
|---|
| Part Number |
71606 |
| Manufacturer |
H.B. Smith |
| Material |
Cast Iron |
| Type |
Split Lock Nut |
| Size |
1-1/2 Inch |
| Compatible Boilers |
Mills 650 Series |
| Application |
Boiler Section Connection / Assembly |
🔁 Cross Reference Table
| Manufacturer | Part Number | Notes |
|---|
| H.B. Smith |
71606 |
OEM replacement |
| Mills |
650 Series |
Boiler compatibility reference |
⚠️ Common Symptoms of a Failing Lock Nut
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Section misalignment or joint separation
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Leaking or pressure loss at section connections
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Rattling or vibration from loose boiler hardware
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Corrosion or cracking on the existing lock nut
❓ Frequently Asked Questions (FAQ)
Q: Is this an original H.B. Smith replacement part?
A: Yes — it’s an OEM replacement designed to match the original Mills 650 boiler hardware.
Q: How is the split nut installed?
A: The two halves are clamped around the section tie rod and tightened evenly to secure the boiler section joint.
Q: Can it be used on other boiler models?
A: It’s designed for Mills 650 units. Check fitment before applying to other Smith models.
🛒 Shopping Tips
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Always replace in pairs for consistent pressure and alignment.
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Check tie rods and gaskets for wear during replacement.
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Keep a spare set on hand to reduce downtime during maintenance.
