Aircraft maintenance tooling

There is a whole industry designing and manufacturing custom aircraft maintenance tooling. Driven by the need of customers to create new capabilities, and with a solid background in component maintenance and tool design, there are always new tooling solutions. There is of course a development risk.

Obviously, there is no need to develop tooling when it can be bought from the market. Below are examples from the market for original tooling through OEM's, authorized manufacturers.

Bench And Floor Tools

Squaring Shears

Squaring shears are aviation maintenance tooling that can be operated either manually or hydraulically. A foot-operated treadle can be inexpensively converted to a hydraulic type by installing a hydraulic power pack on the machine. A hydraulic squaring shear can cut aluminium alloy up to 1/2 of an inch thick and aircraft steel up to 16 gauge

The primary purpose of the side fence is to square metal to the cutting blade. A piece of sheet metal can be squared by placing it beyond the cutter, shearing off one side and turning the metal 90' to make another cut.

Extending from the back of the machine are two rods, which, like the side fence, have a measuring scale embossed on them. Connected to these two rods is a stop fence that can be adjusted for longer cuts. The rods can be set to measure the distance from the cutting blade to the adjusted stop.

For example, if a sheet metal skin is to be cut 10 inches long and has to be squared, slide the skin along the fixed side fence, pushing it until it contacts the stop fence, which has been set at 10 inches. Then cut by stepping on the treadle.

Bending Brakes

There are many different sizes and types of bending brakes. The most versatile and widely used is the box and pan brake. The box and pan brake is fully adjustable and comes in various lengths. It has removable nose pieces that make the construction of a pan rib possible.

The whole brake section can be moved backwards and forwards, allowing the addition of thicknesses of metal to the nose of the brake to increase the radius of the bend. As the bend radius is increased, the nose brake clearance must also be increased.

Straight bending brakes range from four to twelve feet in length. They are usually not adjustable, and it is difficult to install a bend radius bar on the nose of the brake. The straight bending brake is used to make long stringers.

Slip Roller

A slip roller is used to make a cylinder or a duct. The slip roller consists of three rollers interconnected by gears and turned by a hand crank. The rollers can be individually adjusted to produce a tight or a loose roll. After a metal cylinder is formed, it is removed from the roller by activating a release which allows the roller to slip free of its holder at one end. The part can then be removed.

Drill Press

A drill press is used to drill precision holes. Its use on skins is limited by the reach, or distance, between the center line of the spindle and the stand which holds the drill's drive mechanism. It is more commonly used to predrill holes in new spars or stringers.

Slip roll former

The drill press has four main parts: Floor stand, adjustable table, adjustable spindle, and electric motor. The table can be raised upwards toward the spindle to reduce the distance that the spindle has to travel downward to meet the work.

On some drill presses, the spindle has a threaded stop which can be adjusted to control the amount of downward travel and thus allow the drill press to be used as a stop countersink cutter. The drill press electric motor is bolted to the same frame as the spindle. Drill speed is determined by the belt's location on the motor and by the spindle pulleys. If low speed is required for drilling, the small pulley on the motor will be connected to the large pulley on the spindle.

Combination Band Saw

A combination hack and band saw is used when thick sheet metal cannot be cut with the squaring shears. A medium-size combination saw will do most such cutting jobs.

Electric Grinders

The electric grinder is used regularly to sharpen dull or broken drills. A grinder does not have to be large; a small 1/2 to 3/a horsepower motor is adequate. The grinding wheel best suited for sharpening drills is a fine grit stone. When a grinding wheel becomes grooved and uneven, it should be re-dressed and squared with a dressing tool. Care should be taken to avoid dropping the grinding wheel because it can develop small cracks which could later cause the wheel to fly apart and seriously injure the operator.

Note: Never use a grinding wheel that has been dropped or that has a flaw of any kind.

Airframe Special Tools

Tools used for aligning fuselages or supporting wings while they are being repaired are called slings or jigs. Most of the fuselage slings are shop-made for the specific repair to be done. For example, fuselage slings or saddles support the undamaged parts of the fuselage while the damaged parts are being removed.

When a braced wing needs to be repaired and the strut must be removed, a wing jig or stand is placed underneath one of the compression ribs.