Product Bulletin No.: ST80-04-02 Revision A ST-80 Iron Roughneck Release Date: December 15, 2004 Subject: Detachment of Duplex Extension Cylinder/Clevis on ST-80 Product: All ST-80 Iron Roughnecks Affected Assemblies: ST-80 Platform Assembly (P/Ns 30160030 and 30171698) Note: Inspect your serial number nameplate for the last three digits (e.g. ST80A01K001). Affected units include serial number 001 up to and including 091 and serial numbers 301 up to and including 382. Objective: Advise Operators of Cylinder Upgrade to Prevent Possible Clevis Failure Problem: The initial release of this product bulletin notified operators of an incident that occurred when the clevis detached from the Duplex Extension Cylinder (P/N 30170579) while the operator was extending the ST-80 Iron Roughneck to well center. The ST-80 Carriage was approximately one foot from well center when the clevis detached from the rod on the support arm end of the cylinder. As a result, the carriage pivoted forward and came to rest against the drill pipe. No injuries were reported as a result of this incident. The investigation has determined that the cylinder manufacturer may not be installing the rod end clevis on the duplex cylinder to the required torque. A clevis not torqued properly can result in a fatigue failure of the clevis threads and detachment of the clevis from the cylinder rod. Solution: As a precautionary measure Varco has established a plan to provide hardware to upgrade all ST-80 Duplex Extension Cylinders. The upgrade will consist of replacing the two existing clevises with new ones and torquing both to 500 ft-lbs. The Extension Cylinder Upgrade Kit (P/N 30175331) includes two new clevises, a greasable pivot pin and bushings, a special wrench and a kit drawing providing detailed instructions to the rig for implementing this upgrade. ST80-04-02 Rev A Page 1 of 3 To upgrade these duplex cylinders Varco will supply the kit parts only, free of charge. Each ST-80 owner should provide a no cost purchase order to your local Varco Service Center to order the kit. Varco recommends that all ST-80 operators immediately inspect the Duplex Extension Cylinder for loose or damaged clevises. Extension of the ST-80 will be required to verify that no gap exists between the rod end clevises and the rod ends. See Figures 1 & 2. If any damage or gap between the clevises and rod end is observed discontinue use until the kit is received and installed. Please contact your local Varco Service Center if you have any questions regarding this product bulletin. Pedestal Column Carriage Assembly Support Arm Figure 1 ST-80 Iron Roughneck Extension Duplex Cylinder ST80-04-02 Rev A Page 2 of 3 Cylinder Clevis Note: Inspect for gap between clevis and rod end shoulder Support Arm Cylinder Rod Figure 2 Close up View of Duplex Extension Cylinder (Support Arm End) ST80-04-02 Rev A Page 3 of 3 ST80 Index Safety Alert Rev ST80-03-01 - - ST-80 Performance Issues 1/29/03 All H & P ST-80 Iron Roughnecks ST80-03-02 Yes B ST-80 Control Valve Assembly Damaged Resulting in Pinch Hazard 7/7/03 All ST-80 Iron Roughneck ST80-03-03 - - ST-80 Handling Instructions for Lifting and Transport 6/13/03 All ST-80 Iron Roughneck ST80-03-04 - - 6/13/-03 All ST-80 Iron Roughneck ST80-03-05 - - ST-80 Operating Instructions for Positioning ST-80 Instructions for Proper Use of Spinning Wrench Controls 6/13/-03 All ST-80 Iron Roughneck ST80-03-06 - - ST-80 Set-up Instructions for System Pressure Setting 6/13/-03 All ST-80 Iron Roughneck ST80-03-07 - - ST-80 Hose Abrasion 7/7/03 All ST-80 Iron Roughneck ST80-04-01 - - Revisions to Lubrication Frequency on ST-80 5/10/04 ST-80 Wrench ST80-04-02 Yes A Detachment of Duplex Extension Cylinder/Clevis on ST-80 12/15/04 ST-80 Platform Assembly (P/Ns 30160030 and 30171698) Affected units include serial number 001 up to and including 091 and serial numbers 301 up to and including 382. No. Title Date Rel. Effectivity
