Basic Machine Basic Machine ProcessesProcesses

Competency D403.00Competency D403.00

Identify the basic concepts of Identify the basic concepts of the manufacturing processes.the manufacturing processes.

Basic Machine Basic Machine ProcessesProcesses

Objective D403.02Objective D403.02

Explain the ANSI standards of Explain the ANSI standards of applying annotations to a drawing applying annotations to a drawing

that best describes the that best describes the manufacturing process.manufacturing process.

Hole CalloutsHole CalloutsSection ISection I

How Finish Holes Are MadeHow Finish Holes Are Made

The drilling of a common drilled hole is done on a drill press.

Drilling can also be done on a lathe.

DrillingDrilling

Blind

Hole

Is the process used to cut a cylindrical hole with a drill press and drill bit.

BORINGBORINGThru

Hole

Enlarges the hole slightly and makes it rounder and straighter.

ReamingReaming

To enlarge a hole to a more accurate size and

surface quality.

Specialty Tools For Hole DevelopmentSpecialty Tools For Hole Development

ANSI Hole Identification SymbolsANSI Hole Identification Symbols

Diameter

Counterbore / Spotface

Countersink

Depth

Number of holes

Drill HolesDrill Holes - Size & Location Dimensions - Size & Location Dimensions

Always locate a drill hole by a common corner.

(Datum Corner)

Always add dimensions for size

and location, to profile of feature

L

L

ØS

DimensioningDimensioning Repeated HolesRepeated Holes

4X Ø.50

Don’t forget to provide a space

X = Number of holes required.

Blind HoleBlind HoleØ.50 .875

30°

Depth

A blind hole cuts into but does not pass completely through the object.

For blind holes always show a 30 degree bevel end to represent the drilling process.

Depth Symbol

Counterbore CalloutsCounterbore CalloutsØ.50 Ø1.00 .38

Counterbore – To enlarge the end of a drill hole to a specific diameter and depth in order to recess a mating part.

Counterbore

Symbol

Depth

Symbol

Through HolesThrough HolesØ.50

A through hole is one that passes all the way through the object.

The word THRU may be omitted in the annotation of the hole.

Spotface CalloutsSpotface Callouts

Spotface – The cutting of a shallow counterbore, usually about .0625 deep (depth symbol is omitted). A spotface provides an accurate bearing surface for the underside of a bolt head.

Ø.50 Ø1.00

Counterbore

Symbol

Countersink CalloutsCountersink Callouts

Countersink – To recess a hole with a conically (cone) shaped tool to provide a seat for flat head screws. (Does not need a depth to be specified.)

Ø.50 Ø1.00 X 82°

Countersink

SymbolAngle of The

Chamfer

Drawn At

90 Degrees

KnurlsKnurlsSection IISection II

KnurlingKnurling

Straight – parallel groves.

Diamond – crossing diagonal groves.

Common on thumbscrews and handles of to provide a better gripping surface

KnurlingKnurlingDimensioningDimensioning

The most commonly used diametrical pitches (DP) are 64 DP (coarse), 96 DP (medium), 128 DP (fine), and 160 DP (extra fine).

The callouts for a knurl should include the pitch, type, and the diameter.

1.89 .82

Ø1.25

96 DPSTRAIGHT K NURL

As

Seen

As

Drawn

ChamfersChamfersSection IIISection III

External Chamfers DimensioningExternal Chamfers Dimensioning

Bevel edges are normally applied to cylindrical parts.

.25 X 45°

.43

30°

Preferred For 45° Chamfers

Preferred For Angles Other Than 45°

OR

.25 X .25

CHAMFER

Internal Chamfer DimensioningInternal Chamfer Dimensioning

45° .72

Ø4.44

Ø3.06 THRU

Fillets & Fillets & RoundsRounds

Section IVSection IV

Fillets & RoundsFillets & Rounds Sharp corners are weak. They are likely to

yield cracks and other failures in the part. Fillets – are rounded inside corners. Rounds – are rounded outside corners.

Fillets and rounds are normally found Fillets and rounds are normally found on cast, forged, or plastic parts.on cast, forged, or plastic parts.

Rough Cast

RunoutsRunouts

Conventional methods for representing fillets and rounds

Conventional EdgesConventional Edges If an edge has a small radius, a line should be shown. If an edge has a large radius, no line should be shown. Draw lines for edges whenever such lines make the drawing

clearer.

No Line

Surface Texture Surface Texture SymbolsSymbols

Section VSection V

Surface Texture SymbolsSurface Texture Symbols Finish MarksFinish Marks

Tells the machinist which surfaces are to be finished or machined.

ANSI Standard Finish MarkANSI Standard Finish Mark(now in general use)

H = Standard Letter Height For General Notes.

3H1.5H

60°

Rules About Finish MarksRules About Finish Marks Shown on the edge view

of a surface to be finished.

The vertex of the finish mark should point inward toward the solid metal.

Position to read from the bottom of the sheet or from the right side of the sheet.

Rules About Finish MarksRules About Finish Marks

It is repeated in every view where the surface appears as

a line, including hidden lines and curved lines.

Machined Casting

Rules About Finish MarksRules About Finish Marks

Finish marks are not required for drill holes or any other holes where machining operations are clearly illustrated.

Rules About Finish MarksRules About Finish Marks

If a part is to be finished all over, omit the finish marks.

Letter as a general note on the drawing, such as FINISH ALL OVER or FAO.

NOTES:FINISH ALL OVER.FILLETS AND ROUNDS R.125.BREAK SHARP EDGES.

General note

Should be placed near the title block