DDT 9&10 Test

Unified Thread

Most commonly used form for fasteners

Thread Series

Coarse, Fine, Extra Fine

Class 2

Standard for most fastener applications

Class 1

Loosest class of fit

Class 3

Closest class of fit

Thread Pitch

Distance from one point on one thread to another thread

Arrowless

Dimension figures at the end of extension lines or center lines

Single-Lead

One revolution causes an advance of one thread

Form

Shape of a thread

Datum

Arrowless dimensioning is limited to what dimensioning method

External Thread

(A) in a thread spec represents what?

Internal Thread

(B) In a thread spec represents what?

Double-Lead

Each thread advances 2 threads per revoltution

Triple-Thread

Each thread advances 3 threads per revolution

Pitch

TPI = 1/?

TPI

Pitch = 1/?

UN

Unified National

C

Coarse

F

Fine

Major Diameter

(7/16)-14 UNC -1B

TPI

7/16-(14) UNC -1B

Form

7/16-14 (UN)C -1B

Series

7/16-14 UN(C) -1B

Class

7/16-14 UNC -(1)B

Internal External

7/16-14 UNC -1(B)

7/16-14 UNC-1B

Coarse, Major, .438, Unified National, Class 1, Internal

Circular

Preferred view of threaded holes

TYP

Abbreviation used after a single dimension, Avoids repetition

NTS

Heavy line under a revised dimension

Rockwell Hardness

Measures hardness

Repetitive

_____ Features or dimensions may be specified using “X” and the quantity

Revision

A ____ block is used to record changes after released for production

Patent

Exlcudes anyone else from manufacturing or selling a device for 17 years

Detail Drawing

Confined to one object

LD - (Ratio x Length)

SD

SD + (Ratio x Length)

LD