DDT EXAM #1

Parallel

Extending in the same direction, and not meeting

Tolerance

Permissible variation from a given dimension

Datum

Point line surface or plane from which the location of other features is established

Limits

Maximum and minimum dimensions, apply tolerance to basic dimensions

Included angle

The inside angle formed between one side and another

Symmetrical

The same on each side

Non-Ferrous

Without Iron

Extension Spring

A spring that stretches when a force is applied

Flange

Projecting rim or collar on an object

Die

Used to cut external threads

Tap

Used to cut internal threads

Face

Machining a flat surface on an object

Gauge

The thickness of sheet metal or wire designated by a number

Keyseat

Groove in a shaft that positions the key

CAD Drawing

A drawing created by computer aided drafting

Boss

A raised circular projection that provides extra metal around a hole in casting or forging

Pinion

The smallest of two mating gears

Pattern

A model made of wood metal or other material that forms a cavity in the sand for pouring castings

Allowance

Minimum clearance between two mating parts

Radii

Plural of Radius

Quencing

Cooling metals rapidly by submerging in water oil or air

Concentric

Sharing the same center point

Casting

A metal object made by pouring molten metal into a mold

SYM

Symmetrical

SECT

Section

PC

Pitch

HRS

Hot Rolled Steel

CHAM

Chamfer

FAO

Finish All Over

ID

Inside Diameter

SCR

Screw

STL

Steel

BC

Bolt Circle

LG

Length

CSK

Countersink

CI

Cast Iron

MIN

Minimum/Minute

FIN

Finish

REF

Reference

DR

Drill

THD

Thread

THK

Thick

DIM

Dimension