Aircraft Rivets
- Rivet Codes - A rivet is any type of fastener that obtains its clamping action by having one of its ends mechanically upset.
- Airforce Navy - AN
- Military Standards 20 - MS20
- AN 470 AD 4 - 5
- First component of the system denotes the numbering system used (AN/MS20)
- The second component, the 3 digit number, denotes the style of the rivet head
- Universal - 470
- Countersunk- 426
- To ensure head-to-gunset contact, it is recommended that the countersink head protrude about .005-.007 of an inch from the skin of the aircraft.
- To smooth it after installation, use a microshaver.
- To ensure head-to-gunset contact, it is recommended that the countersink head protrude about .005-.007 of an inch from the skin of the aircraft.
- Flat head - 442
- Round Head - 455
- The third is a 1 or 2 digit code representing the alloy in the rivet.
- A - 1100 - Pure aluminum - Plain Head
- Lacks sufficient strength for structural applications
- Used on Fairings, Engine Baffles, and Furnishings.
- Is driven cold so shear strength increases because of cold working.
- AD - 2117 - Copper Alloy - Dimple Head
- High strength and shock resistance
- Most widely used for manufacturers and Maintenance
- B - 5056 - Magnesium - Raised Cross
- Contain about 5% magnesium
- Maximum sheer strength is 28,000 PSI
- D - 2017- Copper Alloy- Icebox rivets - Raised do
- Crack free rivet with shear strength of 34KSI
- Icebox rivets - Kept at freezing temperatures (annealed state) until ready to use. They become hard when they warm up to room temperature.
- DD - 2024 - Copper Alloy - Icebox rivets - Two Raised Dots
- E - 7050 - Zinc Alloy - Raised Ring
- Has been percipitation heat treated
- Staineless steel rivets are used for fastening corrosion resistant steel sheets in applications such as firewalls and exhaust shrouds
- they have no markings
- Monel rivets are identified with two recessed dimples in their head.
- They are used in place of stainless steel rivets where their lower sheer strength is not a detriment.
- A - 1100 - Pure aluminum - Plain Head
- The fourth is the shank diameter, indicated in 1/32 of an inch
- The fifth is the length, indicated in 1/16 of an inch
- Head Design - the two standards used are universal and countersunk
- Counter Sinking - a process in which the metal in the top sheet is cut away in the shape of the rivet head.
- Dimpling - A process that mechanically dents the sheets being joined to accomidate the rivet head.
- Crown Flush Rivets - have a slightly crowned heda to allow full contact with the gun-set
- It forms a fully cold worked rivet that needs no microshaving
- Special Rivets
- Blind Rivets - are installed with access to only one end of the rivet.
- Pop Rivets - have limited use on aircraft and are never used for structural repairs.
- Useful for temporarily lining up holes.
- Available in flat head, countersunk head, and modified flush heads with standard diameters of 1/8, 5/32, and 3/16
- Made from soft aluminum alloy, copper, steel, and monel.
- Friction Lock Rivets (Cherry Friction lock Rivets)
- Still used for repairing light aircraft
- Available in universal and 100 degree countersunk head styles and 1/8, 5/32, 3/16 inch diameters
- larger sizes can be specifically ordered in sizes up to 5/16 in
- A friction lock Can Not replace a solid shank rivet size for size it must be at least one size larger in diameter
- Mechanical-Lock Rivets - Designed to prevent center stem of a rivet from falling out as a result of vibration encountered during aircraft operation by permanently locking the stem into place and vibration can not shake it loose.
- Huck-Locks - were the first mechanical-lock rivets
- Used as structural replacements for solid shank rivets.
- Available in for standard diameters 1/8, 5/32, 3/16 and 1/4 in and come in three different alloy combinations:
- 5056 sleeve with a 2024 pin
- A-286 sleeve with an A-286 pin
- Monel 400 sleeve with a A-286 pin
- Cherrylocks - the center stem is locked into place with a lock ring resulting in shear and bearing strengths that are high enough to allow them to be used for solid shank rivets.
- Two head styles; 100 degree countersunk and universal with diameters of 1/8, 5/32 and 3/16 of an inch with an oversize for each of 1/64
- Made of 2017 aluminum alloy, 5056 aluminum alloy, Monel, or stainless steel.
- a disadvantage is that if a rivet is too short for an application, the lock ring sets prematurely resulting in a malformed shank header.
- Olympic-loks - a light weight spindle type blind rivet, with a lock ring stowed at the head.
- Head styles are universal, 100 degree flush, and 100 degree flush shear. Diameters are 1/8, 5/32 and 3/16 inch
- Alloys are 2017-T4, A-286, 5056, and Monel.
- Cherry Max - IS strong enough to replace solid shank rivets, size for size.
- Composed of five main parts; Pulling stem, a driving anvil, a safe lock locking collar, a rivet sleeve, and a bulbed blind head.
- Available in universal and countersunk head styles in diameters of 1/8, 5/32, 3/15, and 1/4
- Sleeve is made from 5056, Monel, and inco 600
- Stems are made from alloy steel, CRES, and inco x-750
- The ultimate sheer strength is 50ksi to 70ksi at temperatures of 250-1400 degrees F
- Removal of mechanical-lock rivets - (all brands of lock rivets are removed using the same technique)
- You must first file a flat spot on the rivet's center stem.
- a center punch is used to punch out the stem so the lock ring can be drilled out
- then you can tap out the remaining stem
- Then drill out the remaining head
- Huck-Locks - were the first mechanical-lock rivets
- Hi-Shear rivets
- Has the same strength characteristics as a high strength bolt
- It's secured by a crushing collar
- Available in two head styles flat and countersunk.
- Made to withstand high shear loads
- Made from steel alloy having the same tensile strength as an equal size AN bolt
- Special Fasteners
- Lock Bolts There are three type of lock-bolts used in aviation
- Pull-type Lockbolt - Has a pulling stem on which a pneumatic installation gun fits. The gun pulls the materials together and then drives the locking collar into the grooves of the lock-bolt. Once secure the gun fractures the pulling pin at it's breaking point
- Blind-type Lockbolt - To install a blind lock-bolt, it is placed into a blind hole and an installation gun is placed over the pulling stem. As the gun pulls the stem, a blind head forms and pulls the materials together. Once the materials are pulled tightly, a locking collar locks the bolt in place and the stem is broken off.
- Stump-type Lockbolts - Is installed in places where there is not enough room to use the standard pulling tool. The tool is similar to that used in the installation of Hi-Shear rivets.
- Available for both shear and tension applications. With shear lockbolts, the head is kept thin and there are only two grooves provided
- The locking collars used on both shear and tension bolts are color coded for easy identification
- Hi-Loks - Manufactured in several different alloys such as titanium, stainless steel, and aluminum
- Posses sufficient strength to withstnd bearing and shearing loads, and are available with flat and countersunk heads.
- the threads are compatible with standard AN bolts and nuts.
- Hi-Lites - Is made from lighter materials and has a shorter transition from the threaded section to the shank. It's main advantage is its high strength to weight ratio.
- Available in 3/16 - 3/8 in
- Installed with either a Hi-lok lockiing collar or a swaged collar
- Cherrybucks - Is a one-piece special fastener that combines two titanium alloys which are bonded together to form a strong structural fastener
- Composed of 6AL-4V alloy while Ti-Cb alloy is used in the lower shank.
- Since there is only once piece these are safe to install inside jet air intakes
- Taper-Lok - Is the strongest special fasteners used in aircraft
- They exert a force on the conical walls of a hole. It mimics the action of a driven solid shank rivet, however a taper-lok does this without shank swelling.
- Hi-Tigue - Has a bead that encircles the bottom of its shank and is a further advancement in special fastener design
- Available in aluminum, titanium, and stainless steel alloys. The collars are available as sealing, or non-sealing
- Jo-Bolts - Used in close-tolerance holes where strength requirements are high but physical clearance precludes the use of standard AN, MS, or NAS bolts.
- Removal of special fasteners - Split the collar with a small cape chisel. Knock away the two halves and tap the fastener from the hole.
- Threaded Rivets - Rivnuts - Use to attach rubber deicer boots to aircraft wing and tail surfaces.
- Lock Bolts There are three type of lock-bolts used in aviation
page revision: 2, last edited: 03 Nov 2008 18:48