REG NASA-LLIS-0255-1993 Lessons Learned - Grinding Wheel Detachment.pdf

1、Lessons Learned Entry: 0255Lesson Info:a71 Lesson Number: 0255a71 Lesson Date: 1993-08-26a71 Submitting Organization: LERCa71 Submitted by: S. PapellSubject: Grinding Wheel Detachment Description of Driving Event: The Flexovit grinding wheel, National stock number 3460-00-027-0942, abrasive, resin b

2、ound, 7“ by 1/4“, shape 1397, grit 24, was released from a portable air powered grinder, commonly referred to as a “Bayflex Grinder“, just after the grinder was turned off. The grinding wheel was propelled across the room by its inertial force created during the grinding operation.The problem is ass

3、ociated with the size of the flat surface on the nut, which is torqued to the flange on the grinder. The grinding wheels were manufactured with two different flat surface sizes for the nut, 1/16“ and 3/8“. The 1/16“ flat surface may allow the grinding wheel to unthread itself from the grinder when t

4、he air is cut off. The grinding wheel with the 3/8“ flat surface is the correct one to use.Lesson(s) Learned: Grinders that have Flexovit grinding wheels pose a hazard when turned off. The wheels can detach from the flange mount on the grinder and become dangerous missiles.Recommendation(s): Remove

5、all Flexovit grinding wheels from service that have the 1/16 inch flat surface nuts, which are torqued to the flange on the grinder.Evidence of Recurrence Control Effectiveness: N/AProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Documents Related to

6、Lesson: N/AMission Directorate(s): N/AAdditional Key Phrase(s): a71 Hardwarea71 Industrial OperationsAdditional Info: Approval Info: a71 Approval Date: 1994-06-15a71 Approval Name: Maria Havenhilla71 Approval Organization: LERC/EBASa71 Approval Phone Number: 216-977-1483Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-