The Nord-Lock EZ Fit Expansion Bolt is a specialized fastening solution designed primarily for rotating flanges and shaft couplings where eliminating radial movement between the bolt and the hole is critical. It replaces traditional fitted or interference bolts.
How it works: Unlike standard bolts which have clearance in the bolt hole, the EZ Fit Expansion Bolt is designed to radially expand within the hole. This typically involves:
- Inserting the bolt assembly (which often includes a tapered bolt and an expanding sleeve) into the clearance hole.
- As the bolt is tightened axially, the tapered components interact, forcing the sleeve to expand outwards.
- This expansion completely fills the gap between the bolt shank and the hole wall, creating a rigid, zero-clearance connection.
- This ensures a true friction grip and prevents any relative movement between the coupled parts, even under high torque or reversing loads.
- Many designs also incorporate Nord-Lock's signature wedge-locking washers to secure the bolt axially and prevent loosening due to vibration or dynamic loads.
Problems it Solves & Benefits:
- Eliminates Radial Movement: Prevents unwanted play, fretting wear, and potential shear failure in couplings caused by hole clearance.
- No Need for Reaming: Unlike traditional interference bolts that require precisely machined, tight-tolerance holes (often requiring line reaming on-site), the EZ Fit bolts work in standard clearance holes, saving significant installation time and cost.
- Easy Installation & Removal: Installation is typically faster and simpler than pressing in interference bolts. Removal is also straightforward, unlike the often difficult extraction of seized interference bolts.
- Reusability: The bolts are generally designed to be reusable, reducing lifetime costs.
- Improved Safety & Reliability: Creates a more secure and reliable joint, reducing the risk of failure in critical rotating equipment.
- Reduced Downtime: Faster installation/removal and increased reliability contribute to less machinery downtime for maintenance or repairs.
- Handles High Torque & Dynamic Loads: Effectively transfers torque and withstands dynamic or reversing loads without slippage.
