Wednesday, August 12, 2015

The World of Hand-Held Grinders

In the world of the steel fabrication shop, hand-held grinders are used every day.  Although they are fairly innocuous looking tools, they are actually quite hazardous if handled improperly.  And, injuries from these tools can range from minor cuts to amputations, or even worse.

Hand-held grinders are used to grind, or smooth and shape steel to a nice finish before painting.   They are used much like the disk sander that you might use when doing woodwork.  Hand-held grinders in the steel fabrication shop are meant to take several different types of blades, but to keep it simple, let's reduce that to two categories:  1.  a "hard" inflexible disk; and 2. a flexible disk (like a sanding disk or buffing "blade).

            7" Grinder with "hard" disk properly guarded

When using the "hard" disk, a guard is required on the grinder.  The guard is designed to keep pieces of a broken disk from hitting the grinder operator.  Although the guard may protect a workers's fingers, it's primary purpose is to keep broken blade pieces from causing harm.  

With the "flexible" disk, or "sanding" disk, a guard is not required.  The guard might protect the operator's hand from contacting the disk, but remember, the primary purpose of the guard is to protect the worker from flying pieces of a broken disk.
       4.5" grinder with flexible disk and no guard

         4.5" grinder with flexible disk and guard

Are broken "hard" disks common?  Well, not in my experience, but it does happen and there have been deaths as a result of pieces striking workers.  The good news is that with the proper precautions, we can reduce the likelihood of injuries when using hand-held grinders.

  1. Always inspect disks for imperfections, cracks, and other damage.  Performing a "ring" test may help identify cracks that you may not be able to see.
  2. Always follow the appropriate lockout/tagout (LOTO) procedures when changing disks.  In this case, LOTO means unplugging the tool before you change disks or guards.  And, be sure that you keep your hands clear of the trigger plugging it back in.
  3. Wear gloves when operating this tool.  The disks operate at high speed and can "kick" back at you.  Gloves can prevent many minor injuries to your hands.
  4. Never use the grinder above chest height. 
  5. Always wear the appropriate Personal Protective Equipment (PPE).  In this case, at least use safety glasses, hearing protection, gloves, and a face shield.  Our shop reduced eye injuries in our shop by 65% after we required the wearing of face shields in addition to safety glasses.  Although all previous eye injuries were minor, it is evident that face shields work!
Because these tools are potentially hazardous, we conduct training on the use of grinders beginning at safety orientation.  Then, throughout the year, we also conduct tool box safety talks on grinder safety.

Recently, we conducted a tool box safety talk about grinders emphasizing the use of guard and we always end with a reminder of the LOTO procedures.  Imagine my surprise when, about 20 minutes after the training session, I was called the the first aid room to find an employee with a grinder injury.  He had just completed a blade change (a "hard" disk) and had followed the proper LOTO rules.  But, when picking up the grinder to begin work, the glove web between thumb and forefinger contacted the grinder's trigger.  The spinning disk pulled his gloved left forefinger into the blade pinching it between the blade and the guard.  He had an ugly gash on his left forefinger, but luckily, required only a few stitches - no permanent injury.

So, even when you think you are following all of the safety rules, PPE, LOTO, etc., you must always remain diligent when using a grinder.  And always keep you mind focused only on what you are doing.

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