Blind Rivets

Question 1

When are blind rivets used on aircraft?

Answer 1

When there is no access to the other side in which a solid shank rivet requires to be installed. They may also be use to save time, money and weight.

Question 2

All blind rivets rely on the principle in which a ______ or __________ is drawn through a sleeve to form the shop head.

Answer 2

The principle in which a stem or mandrel is drawn through a sleeve to form the shop head.

Question 3

there are three basic types of blind rivets. What are they?

Answer 3

Hollow, pull through
Friction locking
Mechanical locking

Question 4

What kind of applications are hollow, pull through rivets used in and are they suited for aircraft use?

Answer 4

Hollow pull through rivets are non-structural and not suitable for aircraft use. They are used to tack assemblies together as a temporary fastener before the actual fasteners are installed.

Question 5

What is the primary difference between a friction lock rivet and a mechanically locked rivet?

Answer 5

In a friction lock rivet, the stem or mandrel is retained in the rivet body by friction. Mechanical lock rivets have a locking collar or ring that retains the stem in the rivet. This collar resists vibrations that would cause the stem to be lost.

Question 6

Although the strength of a friction lock rivet is close to that of a solid shank rivet, the lack of a mechanical lock increases the risk of the stem falling out due to vibration. T/F?

Answer 6

True.

Question 7

Mechanical lock rivets possess all strength characteristics as solid-shank rivet. Therefore in most cases, they can be a good substitute for solid shanks rivets. T/F?

Answer 7

True

Question 8

When using blind rivets, what are some precautions you must follow to ensure proper installation?

Answer 8

-Use the proper tools
-Blind rivets are lubricated so keep them in the bag they are delivered in until use.
-Quality of the hole and using the correct length are all important factors to form an airworthy rivet.
-Blind rivets may only be used when specified and my not be used to replace solid shank rivets.

Question 9

There concerns when using a blind rivet. Certain applications are not acceptable and inspection intervals are set on certain areas. Where should blind rivets NOT be used and how often must they be inspected?

Answer 9

-Blind rivets are not to be used in high stress areas.
-Blind rivets should not be used in control surface hinges brackets, wing attachment fittings, or fixed tail surface attachments.
-Blind rivets will not be used in a fluid tight joint areas unless specified otherwise.
-Blind rivets must be expected at regular intervals for looseness.

Question 10

What is a particular feature that is seen with Friction cherry lock rivets after you install it?

Answer 10

The stem itself breaks off not flush with the rivet head and must be filed down carefully.

Question 11

As the cherry lock rivet is a friction locking rivet, it is vulnerable to losing its stem in which it derives most of its strength from. Because it’s strength relies mostly on the stem, you may replace this rivet for size-to-size with the original. T/F?

Answer 11

False, you may not replace it for size-to-size with the original.

Question 12

If a solid shank rivet is to be replaced by a friction cherry lock rivet, you must use the next size up diameter wise must be used to compensate for what?

Answer 12

Compensate for the potential loss of the stem.

Question 13

What are Cherrylocs and bulbed Cherryloc rivets and what is the main difference between them and what is the disadvantage of both rivets?

Answer 13

They are essentially the trade name for mechanical locking blind rivets. The primary difference is that the cherrylocs have a normal sized shop head when pulled while the bulbed cherrylocs have a larger shop head when pulled.

The main disadvantage is that despite both being mechanical locking rivets, they require two different nose pieces to pull the stem which makes the process a lot more costly.

Question 14

The Cherrymax Mechanical rivet allows for a single installation tool to be used on all of its varrying head styles. Making it extremely economicaly friendly compared to the cherrylocs. It is essentially the same as the cherryloc rivets, however, there is a difference. What is this difference?

Answer 14

The cherrymax gun has a driving anvil which allows the pulling tool to work with and ensures the stem breaks off flush.

Question 15

As blind rivets are made to replace solid-shank rivets, they come in the standard size as solid-shank rivets do. What are the dimensions?

Answer 15

Diameter of a blind rivet comes in at 32nds of an inch, the length of the shank is also in 16ths of an inch as with a solid shank rivet.

Question 16

Blind rivets also come in oversize. That oversize being __ of an inch larger than the normal diameter of a rivet. This is to install a fastener for what reason?

Answer 16

The oversize being 1/64ths. This is to install a fastener in a hole that may have been damaged while the original rivet was removed.

Question 17

What are Rivnuts?

Answer 17

A rivnut is a type of hollow blind rivet. The main feature is that the fastener is threaded and counterbored on the inside.

Question 18

Is the Rivnut a structural rivet? What components use rivnuts to fasten them?

Answer 18

The Rivnut is mostly used as a non-structural nut plate. It was designed to hold de-icing boots on flight surfaces. It is also used to hold accessories to fixtures.

Question 19

What are the two primary head styles rivnuts come in?

Answer 19

Countersunk or flat headed.

Question 20

Most rivnuts possess a tab or key below the head which fits into a notch in the skin which is to prevent the head from spinning. However, a rivnut without a key beneath the head is used in what kind of repairs?s

Answer 20

A rivnuts with no key beneath the head may be used in straight blind riveting repairs where no torque loads are imposed.

Question 21

The opposite end of rivnuts are either open or close. Where are the enclosed ones used?

Answer 21

Enclosed ones are used in pressurized areas or in areas where they may be exposed to water such as on an amphibious aircraft.

Question 22

What does Grip length on a rivnut relate to?

Answer 22

It relates to the unthreaded portion of the body.

Question 23

Rivnuts come in how much size increments?

Answer 23

6 size increments.

Question 24

For example. 6-45, what does 6 and 45 refer to?

Answer 24

6 refers to the screw size while 45 refers to its grip length.

Question 25

Fun question, how can you tell if a rivnut is a flat head or a countersunk head from the grip length?

Answer 25

If the last two or three numbers in the code are divisible by five, it is a flat head. If not divisible by five, then it is a countersunk.