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NSLS ESH Highlight #34

Injury To Hand While Operating A Lathe At The NSLS

Date: November 21, 2003
Editor: N. Gmür

On September 4, 2003 a worker set up a piece of 3/8" brass tubing in a lathe in the NSLS User Machine Shop such that the end of the tubing extended, unsupported, 13" beyond the collet drawer bar take-up wheel of the head stock. At the time, the lathe setting was 900 rpm for the low speed range. The worker successfully machined the ID of the tubing, working in the safe low speed range of 900 rpm. He then prepared to reduce the tubing OD. After changing the tooling, he inadvertently and momentarily activated the lathe in the high speed range (2700 rpm), causing the brass tubing extension to bend and whip around at nearly a right angle. Upon realizing he was in high speed range, the operator immediately switched the lathe into low speed and then to the off position to shut down the lathe. While switching over to low speed, his hand accidentally encountered the whirling extended tubing, thus causing an injury to his hand. The operator reported the accident and injury to the shop supervisor (the shop supervisor informed NSLS safety and management personnel). The operator went to the BNL Clinic where personnel administered first aid for lacerations. He was driven to a local hospital where he received additional treatment in the emergency room.

How can such an injury be prevented?
  1. If excess material is not necessary, cut off any stock extending beyond the collet take-up wheel. This will reduce material that can bend and injure workers or nearby personnel.

  2. If material extending from the head stock is necessary, provide proper supports, as covered in the shop training modules. Supports will prevent material from bending.

  3. If a job requires slow speed, such as 900 rpm, adjust the high range setting to 900 rpm before inserting the stock. No matter which direction the speed range lever is moved, the stock will not overspeed.