Sheet Metal Test 2

If two sheets are held together the rivet is in

single shear

If 3 sheets are together, the rivet may be in

double sheer

Edge distance should be _____ for universal head rivets

2-5D

Edge distance should be _____ for flush head rivets

2\.5-5D

Edge distance is measured to the

center of the rivet

Rivet Pitch should be _______ for universal head rivets

3-12D

Rivet Pitch should be _____ for flush head rivets

3\.5-12D

Transverse Pitch (second row of rivets) should be ______ of rivet pitch

75%

**Mold Point** is the

theoretical location of the turn.

***Setback*** is the

distance that we begin the turn before (and end after) the mold point

***Bend Radius*** is the

amount that we round off the corner

***Bend Allowance*** is the

amount of material we use in the real bend.

Setback formula (90 degrees)

SB = MT + BR

Bend allowance formula

BA = 1.57BR + .702MT

What is the value of the bend tangent lines

1BR

Bend allowance formula (not 90 degrees)

(0.0078MT + 0.01743BR) x degrees

Setback formula (not 90)

K(MT + BR)

stop drilling is used to

stop cracks from progressing

relief holes are used when

bending two flanges that come against each other.

Relief holes should just touch the intersection of

the two inside BTL’s.

Sheet metal tends to ____ along grain lines

fail, much stronger across grain lines.

The general rule for finding the proper rivet diameter is

three times the thickness of the thickest sheet

What is the minimum edge distance for aircraft rivets?

Two times the diameter of the rivet shank

What is the minimum spacing for a single row of aircraft rivets?

Three times the diameter of the rivet shank.

A factor which determines the minimum space between rivets is the

diameter of the rivets being used.

Which of the following need not be considered when determining minimum rivet spacing?

rivet length

Parts fabricated from Alclad 2024- T3 aluminum sheet stock must have all

scratches, kinks, tool marks, nicks, etc., must be held to a minimum.

Joggles in removed rivet shanks would indicate partial

shear failure

The purpose of a joggle is to

allow clearance for a sheet or an extrusion.

The sharpest bend that can be placed in a piece of metal without critically weakening the part is called the

minimum radius of bend.

Unless otherwise specified, the radius of a bend is the

inside radius of the metal being formed

When a piece of aluminum alloy is to be bent using a minimum radius for the type and thickness of material,

the layout should be made so that the bend will be 90° to the grain of the sheet.

If it is necessary to compute a bend allowance problem and bend allowance tables are not available, the neutral axis of the bend can be

found by adding approximately one-half of the stock thickness to the bend radius.

The most important factors needed to make a flat pattern layout are

the lengths of the legs (flat sections).

A piece of sheet metal is bent to a certain radius. The curvature of the bend is referred to as the

bend radius

Which rivets should be selected to join two sheets of .032- inch aluminum?

MS20470AD-4-4.

Rivet pitch is the distance between the

centers of adjacent rivets in the same row

Rivet gauge, or transverse pitch is the distance between the

centers of rivets in adjacent rows.

A single-lap sheet splice is to be used to repair a section of damaged aluminum skin. If a double row of 1/8-inch rivets is used, the minimum allowable overlap will be

13/16in

How many MS20470 AD-4-6 rivets will be required to attach a 10 x 5 inch plate, using a single row of rivets, minimum edge distance, and 4D spacing?

56

A piece of flat stock that is to be bent to a closed angle of 15° must be bent through an angle of

165

The flat layout or blank length of a piece of metal from which a simple L- shaped bracket 3 inches by 1 inch is to be bent depends upon the radius of the desired bend. The bracket which will require the greatest amount of material is one which has a bend radius of

1/8”

On a sheet metal fitting layout with a single bend, allow for stretching by

subtracting the setback from both legs.

The sight line on a sheet metal flat layout to be bent in a cornice or box brake is measured and marked

one radius from either bend tangent line

When bending metal, the material on the outside of the curve stretches while the material on the inside of the curve compresses. That part of the material which is not affected by either stress is the

neutral line