Chapter 11. Safety, Ground Operations, & Servicing
Safety Around Machine Tools
Hazards in a shop’s operation increase when the operation
of lathes, drill presses, grinders, and other types
of machines are used. Each machine has its own set of
safety practices. The following discussions regarding
precautions should be followed to avoid injury.
The drill press can be used to bore and ream holes, to
do facing, milling, and other similar types of operations.
The following precautions can reduce the chance
of injury:
- Wear eye protection.
- Securely clamp all work.
- Set the proper RPM for the material used.
- Do not allow the spindle to feed beyond its limit
of travel while drilling.
- Stop the machine before adjusting work or
attempting to remove jammed work.
- Clean the area when finished.
Lathes are used in turning work of a cylindrical nature.
This work may be performed on the inside or outside
of the cylinder. The work is secured in the chuck to
provide the rotary motion, and the forming is done by
contact with a securely mounted tool. The following
precautions can reduce the chance of injury:
- Wear eye protection.
- Use sharp cutting tools.
- Allow the chuck to stop on its own. Do not attempt
to stop the chuck by hand pressure.
- Examine tools and work for cracks or defects
before starting the work.
- Do not set tools on the lathe. Tools may be caught
by the work and thrown.
- Before measuring the work, allow it to stop in the
lathe.
Milling machines are used to shape or dress; cut gear
teeth, slots, or key ways; and similar work. The following
precautions can reduce the chance of injury:
- Wear eye protection.
- Clean the work bed prior to work.
- Secure the work to the bed to prevent movement
during milling.
- Select the proper tools for the job.
- Do not change the feed speed while working.
from the work.
- Ensure all clamps and bolts will pass under the
arbor.
Grinders are used to sharpen tools, dress metal, and
perform other operations involving the removal of
small amounts of metal. The following precautions
can reduce the chance of injury:
- Wear eye protection even if the grinder has a
shield.
- Inspect the grinding wheel for defects prior to use.
- Do not force grinding wheels onto the spindle.
They fit snugly, but do not require force to install
them. Placing side pressure on a wheel could
cause it to explode.
- Check the wheel flanges and compression washer.
They should be one-third the diameter of the
wheel.
- Do not stand in the arc of the grinding wheel while
operating, in case the wheel explodes.
Welding should be performed only in designated areas.
Any part to be welded should be removed from the
aircraft, if possible. Repair would then be accomplished
in the welding shop under a controlled environment.
A welding shop should be equipped with proper tables,
ventilation, tool storage, and fire prevention and extinguishing
equipment.
Welding on an aircraft should be performed outside, if
possible. If welding in the hangar is necessary, observe
these precautions:
- During welding operations, there should be no
open fuel tanks, and no work on fuel systems
should be in progress.
- No painting should be in progress.
- No aircraft are to be within 35 feet of the welding
operation.
- No flammable material should be in the area
around the welding operation.
- Only qualified welders should be permitted to do
the work.
- The welding area should be roped off and placarded.
- Fire extinguishing equipment of a minimum rating
of 20B should be in the immediate area with 80B
rated equipment as a backup. These ratings will
be explained later in this chapter.
- There should be trained fire watches in the area
around the welding operation.
- Aircraft being welded should be in towable
condition, with a tug attached, and the aircraft
parking brakes released. A qualified operator
should be on the tug, and mechanics available to
assist in the towing operation should it become
necessary to tow the aircraft. If the aircraft is in
the hangar, the hangar doors should be opened.
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