Aviation Maintenance Practices II Prelim B PDF

Aviation Maintenance Practices II Prelim B  Learning objectives: By the end of this week, learners will be able to: Identify and utilize the tools essential for riveting and dimpling. Perform inspections on riveted joints, ensuring quality and structural integrity. Rivet Inst...

Aviation Maintenance Practices II Prelim B  Learning objectives: By the end of this week, learners will be able to: Identify and utilize the tools essential for riveting and dimpling. Perform inspections on riveted joints, ensuring quality and structural integrity. Rivet Installation Tools Hand Tools  Rivet Cutter Rivet cutter is used to trim rivets when rivets of the required length are unavailable. To use the rotary rivet cutter: 1. Insert the rivet in the correct hole 2. Place the required number of shims under the rivet head 3. Squeeze the cutter as if it were a pair of pliers.  Bucking Bar Bucking bar, sometimes called a dolly, bucking iron, or bucking block, is a heavy chunk of steel whose counter vibration during installation contributes to proper rivet installation.  Hand Rivet Set A hand set rivet is a specialized tool designed with a die for the purpose of driving the specific type of rivet. Types of rivet sets: 1. Universal rivets 2. Flush or flat sets  Countersinking Tool Countersinking is a tool that cuts a cone-shaped depression around the rivet hole to allow the rivet to set flush with the surface of the skin. Countersinks are made with angles to correspond with the various angles of countersunk rivet heads.  Countersinking Tool Special microstop countersinks (commonly called stop countersinks) are available that can be adjusted to any desired depth and have cutters to allow interchangeable holes with various countersunk angles to be made. Riveting Power Tools  Pneumatic Rivet Gun The pneumatic rivet gun is the most common rivet upsetting tool used in airframe repair work. Pneumatic guns operate on air pressure of 90 to 100 pounds per square inch and are used in conjunction with interchangeable rivet sets. Pneumatic Rivet Gun  Riveting Process The riveting process involves holding the rivet gun with the correct header (rivet set) snugly against the rivet head. A bucking bar of appropriate weight is held against the opposite end to absorb the gun’s force, preventing damage to the structure The rivet gun, triggered by the operator, delivers blows to drive and upset the rivet.  Precaution 1. Never point the rivet gun at anyone, and use it solely for driving or installing rivets. 2. Depress the trigger only when the set is held against wood or a rivet. 3. Disconnect the air hose when the gun is not in use for an extended period.  Rivet Sets/Headers Pneumatic rivet guns utilize interchangeable rivet sets or headers, with each set designed to fit specific rivet types and work location.  Rivet Sets/Headers Flush headers come in various sizes: Small flush headers – concentrate the driving force in a small area for maximum efficiency. Larger flush headers – spread the driving force over a larger area and are used for the riveting of thin skins. Compression Riveting  Compression Riveting Compression riveting, also known as squeezing, is a riveting method with limited applicability. It is primarily used over the edges of sheets or assemblies where conditions permit, and the rivet squeezer can reach deep enough.  Types of Rivet Squeezers There are three main types of rivet squeezers: 1. Hand rivet squeezer 2. Pneumatic Rivet Squeezer 3. Pneudraulic Rivet Squeezer Riveting Procedure  Riveting Procedure Riveting procedure consists of: 1. Hole transfer 2. Hole preparation 3. Drilling 4. Driving the rivets Hole Transfer  Hole Transfer Transfer holes from a drilled part to another by placing the second part over the first and using established holes as a guide. Alternatively, scribe hole locations from a drilled part onto the part to be drilled, spot with a center punch, and drill Hole Preparation  Hole Preparation Rivet holes must be of the correct size and shape and free from burrs Too small holes may scratch the rivet coating, while too large holes reduce joint strength. Countersinking methods should be adopted as needed, considering metal thickness. Drilling  Drilling Drilling can be done with either a light power drill or a hand drill. The standard shank twist drill is commonly used for rivet holes.  Drill Bit Sizes Rivet hole sizes should be the smallest that allows easy insertion, approximately 0.003-inch larger than the shank diameter’s largest tolerance. NOTE: Recommended clearance drill bits for common rivet diameters are usually specified in documents or manuals.  Drilling Procedure 1. Ensure that the bit is the correct size and shape of the intended hole. 2. Place the drill in the center-punched marker, and if using a power drill, rotate the bit a few turns before starting the motor 3. Maintain a 90 degree angle between the drill and the work or curvature of the material  Drilling Procedure 4. Avoid applying excessive pressure, let the bit do the cutting, and never push the bit through the stock. 5. After drilling, remove burrs with a countersink or file. 6. Clean away all drill chips to ensure a clean working area. Driving the Rivet  Driving the Rivet Riveting equipment, whether stationary or portable, is commonly used in airframe repair work to drive solid shank rivets. Who can perform the operation? 1. Solo or Individual 2. Team riveting or two technician 2.1 Signaling system (tap code) Inspection after Rivet Installation  Inspection after Rivet Installation After the rivet is installed, check for any evidence of rotation or looseness in the riveted parts. After trimming, examine for tightness by applying a force of 10 pounds to the trimmed stem.  Inspection after Rivet Installation A tight stem indicates an acceptable rivet installation Any degree of looseness suggests an oversize hole, necessitating the replacement of the rivet with an oversize shank diameter rivet  Inspection after Rivet Installation A rivet installation is considered satisfactory when: 1. The rivet head is seated snugly against the item to be retained 2. A 0.005-inch feeler gauge should not go under the rivet head for more than the half the circumference. 3. The stem is proven tight. Four Method of Flush Riveting A Walt Disney Industrial Training Film Removal of Rivets  Removal of Rivets The following steps outline the procedure for removing universal or protruding head rivets: 1. Prepare for drilling 2. Drilling process 3. Head removal 4. Shank removal  Removal of Rivets (Countersunk rivets) The following steps outline the procedure for removing countersunk rivets: 1. Drilling process 2. Head removal 3. Shank removal