19591433 Bridgeport Milling Machine Operation Student Handout

5/23/2018 19591433 Bridgeport Milling Machine Operation Student Handout

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Milling Machine Operations

03/05/2004



TABLE OF CONTENTS

Lesson 1 Objectives........................................................................................................ .....3Vertical Mill 4Milling Machine Accessories....................................................... ............................23Common Milling Cutters...................................................................... ...................24Metal Saws 24n! Mills 2"

#$Slot Cutter 2"%ovetail Cutter................................................................................................ .......2"&oo!ru'' (e)seat Cutter........................................................... .............................2"*l)cutters 2+Cutting S,ee!s an! *ee!s....................................................................... ...............2+Calculating S,ee!s an! *ee!s............................................................... .................2+Milling Machine Sa'et)........................................................................................... .3-

Lesson 2 Objectives.................................................................................................... .......32Milling Machine Set$,........................................................................... ................33Alignment #echni/ues................................................................... .........................33Common Milling Machine O,erations.................................................................. ....34Mill O,erations...................................................................................... .................34Alignment o' the 0ea!.............................................................. .............................34Machining a *lat Sur'ace.................................................................. ......................3"S/uaring &or on a Milling Machine................................................ .......................3"Machining the n!s S/uare............................................................... .....................3Machining an Angular Sur'ace................................................................ ................3Cutting Slots an! (e)wa)s............................................................ .........................3

&oo!'u'' (e)s4-



Milling Machine Operationsage 3 o! 3"

CO#$SE TE$M%NAL OB&ECT%'E

Given a job assignment requiring the use of a milling machine, the MaintenanceMechanic will describe the components of the milling machine and the variousoperations that can be performed. Mastery will be demonstrated by the completionof a comprehensive written examination with a minimum score of 80 complete.

LESSON ONE TE$M%NAL OB&ECT%'E

Given a job assignment requiring the use of a milling machine, the Maintenance

Mechanic will describe the components and accessories of a milling machine.

LESSON ONE ENABL%N( OB&ECT%'ES

!"#$ %escribe the components of a vertical milling machine

!"&$ 'dentify and state the purpose of the common milling machine accessories.

!"($ 'dentify and state the purpose of the common milling cutters.

!")$ *tate the methods for determining the proper cutting speeds, feeds, and depthof cut for various materials and cutters.

!"+$ *tate the safety precautions when woring on a milling machine.




-he

standard

vertical

milling

machine has the cutter spindle mounted in a vertical position. -he head on most vertical milling

machines may be swiveled, which readily permits the machining of angular surfaces. -he cutters

used are of the end mill or shell end mill types. -his type of machine is particularly suited to the use

of the rotary table, permitting the machining of circular grooves and positioning of holes that have

been laid out with angular measurements.

A$TS OF T)E $AM*T+E

'E$T%CAL M%LL

-he baseis made of ribbed cast iron. 't

may contain a coolant reservoir.

-he columnis often cast integrally withthe base. -he machined face of the column

provides the ways for vertical movement of

the nee. -he upper part of the column is

machined to receive a turreton which the

overarm is mounted.

-he overarmis round, or of the ram type.

't may be adjusted toward or away from the

column to increase the capacity of the

machine.

-he headis attached to the end of the

ram. rovision is made to swivel the headin one plane. "n universal$type machines,

the head may be swiveled in two planes.

Mounted on top of the head is the motor

which provides the drive to the spindle.

-he spindle may be fed by means of a hand

lever, a handwheel, or automatic power

feed. Most machines are equipped with a

micrometer quill stop for precision drilling

or boring to depth.

-he kneemoves up and down on the face

of the column and supports the saddle and the table. /ertical milling machines are normally equippedwith plain tables only.

EO0,* -ESC$%BE T)E COMONENTS OF A 'E$T%CAL

M%LL%N( MAC)%NE




-he turret pivots the entire upper assembly for special setups or to use the slotting attachment

accessory1.

-he following pages describe, in detail, the head controls for the 2ridgeport Mills.



Milling Machine Operationsage . o! 3"



Milling Machine Operationsage " o! 3"



Milling Machine Operationsage o! 3"



Milling Machine Operationsage ,0 o! 3"



Milling Machine Operationsage ,, o! 3"



Milling Machine Operationsage ,. o! 3"



Milling Machine Operationsage ," o! 3"



Milling Machine Operationsage , o! 3"



Milling Machine Operationsage 2, o! 3"




M%LL%N( MAC)%NE ACCESSO$%ES

3 wide variety of accessories, which greatly increase its versatility and productivity, are

available for the milling machine. -hese accessories may be classified asfixturesor attachments.

Fi1tres 3 fixture is a wor holding device fastened to the table of a machine or to a

machine accessory, such as a rotary table. 't is designed to hold worpieces that cannot readily be

held in a vise or in production wor when large quantities are to be machined. -he fixture is

generally custom designed so that the identical parts will be positioned exactly and held securely.

Attachents Milling machine attachments may be divided into three classes4

#. -hose designed to hold special attachments5 these are attached to the spindle and

column of the machine.

&. Arbors, colletsand adapterswhich are designed to hold standard cutters. -hese are

mounted in the spindle.

(. -hose designed to hold the worpiece, such as a vise, rotary table, and indexingor

dividing head.

Milling machine vises are the most widely used wor$holding devices for milling5

they are available inthree styles4

-heplain vise

may be bolted to the

table so that its jaws are

parallel or at right angles

to the 67 axis. -he

vise is positioned

quicly and accurately

by eys on the bottom

which fit into -$slots on

the table.

EO2- IDENTIFY AND STATE THE PURPOSE OF THE COMMON

MILLING MACHINE ACCESSORIES.




-he swivel base viseis similar to the

plain vise, except that it has a swivel base that

enables the vise to be swiveled through (90"in a

hori:ontal plane.

-he universal visemay be swiveled

through (90"in a hori:ontal plane and may be

tilted from 0 to ;0"in a vertical plane. 't is used

primarily by toolmaers, moldmaers, and

diemaers,

since it permits the setting of compound angles for milling.

/ises are a piece of precision equipment. %on(& $ (>#9in. 2ecause of their thin

cross section, they should be operatedat approximately one$quarter to one$

eighth of the feed per tooth used for

other cutters. -he arbor nut should be

pulled up as tightly as possible by hand

only. %o not use any cheaters, use the

wrench onl6.

EO3- IDENTIFY AND STATE THE PURPOSE OF

THE COMMON MILLING CUTTERS




EN- M%LLS

!nd mills have cutting teeth on the end as well as on the periphery and are fitted to the spindle

by a suitable adapter. -hey are of two types, the solid end millin which the shan and cutter are one

piece, and the shell end mill, which uses a separate shan.

*olid end mills, generally smaller than shell end mills, may have either straight or helical

flutes. -hey are available with straight and tapered shans and with two or more flutes. ?hen a slot

is cut with a two$flute end mill, the depth of cut should not exceed one$half the diameter of the cutter.

?hen the four$flute end mill is used for slot cutting, it is started at the edge of the metal.

T*SLOT C#TTE$

-he -$slot cutter @ig. #A$31 is

used to cut the wide hori:ontal groove at

the bottom of a -$slot after the narrow

vertical groove has been machined with

an end mill. 't consists of a small sidemilling cutter with teeth on both sides and a shan for mounting.

-O'ETA%L C#TTE$

-he dovetail cutter @ig. #A$21 is similar to a single$

angle milling cutter with an integral shan. %ovetail cutters

are available with an internal thread to be mounted on a

special shan. -hey are used to form the sides of a dovetail

after the tongue or groove has been machined with a side

milling cutter. %ovetail cutters are available with )+, +0, ++,

or 90

"

angles.

OO-$#FF 7E+SEAT C#TTE$

-he ?oodruff eyseat cutter is similar to

a plain and side milling cutter. *maller si:es are

made with a solid shan and straight teeth5 larger

si:es are mounted on an arbor and have

staggered teeth. -hey are used for milling semi$

cylindrical eyseat in shafts.



Milling Machine Operationsage 2. o! 3"

FL+C#TTE$S

-he flycutter is a single$pointed cutting

tool with the cutting end ground to the

desired shape. 't is mounted in a special

adapter or arbor. *ince all the cutting is

done with one tool, a fine feed must be

used. -hey are used in experimental wor

where the high cost of a special cutter

would not be warranted.

CALC#LAT%N( C#TT%N( SEE-S AN- M%LL%N( FEE-S Spee8 "ne of the most

important factors affecting the efficiency of a milling operation is cutter speed. -he cutting speed of

a metal may be defined as the speed, in surface feet per minute sfm1 at which the metal may be

machined efficiently. ?e will refer to surface feet per minute as cutting speed. ?hen wor ismachined on a lathe, it must be turned at a specific number of revolutions per minute rpm1,

depending on its diameter, to achieve the proper cutting speed. ?hen wor is machined in a milling

machine, the cutter must be revolved at a specified rpm, depending on its diameter, to achieve the

proper cutting speed.

*ince different types of metals vary in hardness, structure, and machinability, different cutting

speeds must be used for each type of metal and for various cutter materials. *everal factors must be

considered when determining the proper rpm at which to machine a metal4

-he type of wor material

-he cutter material

-he diameter of the cutter -he surface finish required

-he depth of cut being taen

-he rigidity of the machine and wor setup

EO4* STATE T)E MET)O-S FO$ -ETE$M%N%N( T)E$OE$ C#TT%N( SEE-S9 FEE-S9 AN- -ET) OF

C#T FO$ 'A$%O#S MATE$%ALS AN- C#TTE$S



Milling Machine Operationsage 2" o! 3"

-o get optimum use for a cutter, the proper speed at which the cutter should be revolved must

be determined. ?hen machining mild steel, a high speed cutter would have to achieve a surface

speed of about ;0 ft>min. *ince the diameter of the cutter affects this speed, it is necessary to

consider the diameter in the calculation. -he following example illustrates how the formula is

developed.

E:AMLE

Balculate the speed required to revolve a ($inch diameter high$speed steel milling

cutter when cutting machine steel.

#. @irst, determine the circumference of the cutter. Bircumference of Butter C ( inches x (.#)#9

&. -o determine the proper cutter speed or DM, it is necessary only to divide the cutting speed

B*1 by the circumference of the cutter4

B* ft1

DM C circumference in.1

C ;0

( x (.#)#9

*ince the numerator is in feet and the denominator in inches, the numerator must be changed

to inches and the formula simplified4

) x B*

DM C %

3lthough these formulas are helpful in calculating the cutter spindle1 speed, it should be

remembered that they are approximate only, and the speed may have to be altered because of

the metal and>or the machine condition. 2est results may be obtained if the following rules

are observed4

@or longer cutter life, use the lower B* in the recommended range.




Enow the hardness of the material to be machined.

?hen starting a new job, use the lower range of the B* and gradually increase to the

higher range if conditions permit.

'f a fine finish is required, reduce the feed rather than increase the cutter speed.

-he use of coolant, properly applied will generally produce a better finish and

lengthen the life of the cutter because it absorbs heat, acts as a lubricant, and washes

chips away.

Fee8 Milling machine feed may be defined as the distance in inches per minute that the

wor moves into the cutter. "n most milling machines, the feed is regulated in inches per minute

'M1 and is independent of the spindle speed. -his arrangement permits faster feeds for larger,

slowly rotating cutters. -he milling feed is determined by multiplying the chip si:e chip per tooth1desired, the number of teeth in the cutter and the rpm of the cutter. Bhip per tooth B-1 is the

amount of material which should be removed by each tooth of the cutter as it revolves and advances

into the worpiece.

-he feed rate used on a milling machine depends on a variety of factors4

-he depth and width of cut

-he design or type of cutter

-he sharpness of the cutter

-he worpiece material

-he strength and uniformity of the worpiece

-he type of finish and accuracy required

-he power and rigidity of the machine

3s the wor advances into the cutter, each successive tooth advances into the wor an equal

amount, producing chips of equal thicness. 't is this thicness of the chips or the feed per tooth,

along with the number of teeth in the cutter, which form the basis for determining the rate of feed.

-he ideal feed rate may be determined as follows4

@eed C number of teeth x feed>tooth x cutter rpm

-he formula used to find the wor feed in inches per minute is4

'M C F x B- x DM

F C number of teeth in the cutter

B- C chips per tooth for a particular cutter and metal

DM C revolutions per minute of the spindle




E:AMLE

@ind the feed in inches per minute using a (.+$inch diameter #&$tooth helical cutter to

cut machine steel B* 801. 't would first be necessary to calculate the proper rpm for

the cutter4

) x B* ) x 80

DM C % C (.+ C ;#

@eed 'M1 C F x B- x DM

C #& x 0.0#0 x ;#

C #0.; or ##

-he calculated feeds would be possible only under ideal conditions, it is suggested that the

milling machine feed be set to approximately one$third or one$half the amount calculated. -he feed

can then be gradually increased to the capacity of the machine and the finish desired.

-epth o! ct ?here smooth accurate finish is desired, it is considered good milling practice

to tae a rough and finishing cut.

Doughing cuts should be deep, with a feed as heavy as the wor and the machine will allow.

eavier cuts may be taen with helical cutters having fewer teeth since they are stronger and

have a greater chip clearance than cutters with more teeth.

@inishing cuts should be light, with a finer feed than is used for roughing cuts. -he depth of

the cut should be at least #>9)inch. Highter cuts and extremely fine feeds are not advisable

since the chip taen by each tooth will be thin and the cutter will rub on the surface of the

wor, rather than bite into it, dulling the cutter. ?hen a fine finish is required, the feed should

be reduced rather than speeding the cutter up. More cutters are dulled by high speeds than by

high feeds.

-o prevent damage to the finished surface, never stop the feed when the cutter is revolving

over the worpiece. @or the same reason, move the cutter before returning the wor to the

starting position upon completion of the cut.




M%LL%N( MAC)%NE SAFET+

-he milling machine, lie any other machine, demands the total attention of the operator and a

thorough understanding of the ha:ards associated with its operation. -he following points should be

observed when operating the milling machine4

2e sure that the wor and cutter are mounted securely before taing a cut.

3lways wear safety glasses.

?hen mounting or removing milling cutters, always hold them with a cloth to avoid the sharp

edges.

?hen setting up wor, move the table as far as possible from the cutter to avoid any injury.

2e sure that the cutter and machine parts will clear the wor before maing any cut.

Fever attempt to mount, measure, or adjust wor until the cutter is completely stopped. %o

not attempt to stop the cutter with your hand.

Eeep hands, brushes, and rags away from a revolving milling cutter at all times.

?hen using milling cutters, do not use an excessively heavy cut or feed. -his can cause thecutter to brea and the resulting flying pieces may cause injury.

3lways use a brush, never a rag, to remove the cuttings after the cutter has stopped revolving.

Fever reach over or near or around a revolving cutter5 eep hands at least #& inches from the

revolving cutter.

EO5- STATE THE SAFETY PRECAUTIONS WHEN

WORKING ON A MILLING MACHINE



Milling Machine Operationsage 3, o! 3"

Eeep the floor around the machine free of chips, oil, and cutting fluid.




LESSON TO TE$M%NAL OB&ECT%'E

Given a job assignment that requires the performance of milling machine operations,

the Maintenance Mechanic will describe the proper set$up and performance of the

various milling machine operations.

ENABL%N( OB&ECT%'ES

!"#$ %escribe the proper set$up of a milling machine for various milling machine

operations.

!"&$ %escribe the more common milling operations performed on a vertical milling

machine.




AL%(NMENT TEC)N%;#ES

?hen a worpiece is mounted in a

milling machine vise, the vise must be

properly aligned. Generally, the stationary

jaw of the vise must be either at right

angles to the face of the machine column,or it must be parallel with the face of the

column. Dight angle squareness of the

vise with the column can be checed by

placing the blade of a precision steel

square against the stationary jaw of the

vise while placing the beam of the square

against the machined surface of the

column.

3nother method to chec alignment is to place

parallel bars between the machine column and theangle plate. Fo light should show between the

parallel and the column.

-his is done for rough alignment. @inal

3lignment is to be done with dial indicator.

arallelism of the stationary jaw can be

checed with a dial indicator within .00#-'D1.Blamp the indicator to the spindle with the

plunger touching the stationary vise jaw.

Borrect any misalignment.

EO,* -ESC$%BE T)E $OE$ SET*# OF A

M%LL%N( MAC)%NE FO$ 'A$%O#S M%LL%N(

OE$AT%ONS




'E$T%CAL M%LL%N( MAC)%NE OE$AT%ONS

-he vertical milling machine offers a great deal of versatility. -he vertical milling machine

can be used for machining flat surfaces, angular surfaces, drilling, boring, and machining eyways

and circular grooves.

AL%(NMENT OF T)E 'E$T%CAL )EA-

roper alignment of the head is important when machining holes, pocets or when face

milling. 'f the head is not at an angle of ;0"to the table, the holes will not be square with the wor

surface when the cutting tool is fed. ?hen face milling, the machined surface will be stepped if the

head is not square with the table. 3lthough all heads are graduated in degrees and some have vernier

devices for setting the head, it is a good idea to chec the spindle alignment.

#. Mount a dial indicator on the spindle at ;0",

on a suitable rod.

&. osition the indicator over the top of the

table.

(. Barefully lower the spindle until the indicator

button touches the table and the dial indicator

registers about a half of a revolution. *et the

indicator to :ero and loc the spindle in place.

). Barefully rotate the vertical mill spindle #80"

by hand until the button bears on the opposite

side of the table. Bompare the two readings.

*hould be less than .00#-'D1

+. 'f there is any discrepancy in the readings,

loosen the locing nuts on the swivel mountingand adjust the head until the indicator registers

one$half the difference between the two

readings. -ighten the locing nuts.

9. Dechec the accuracy of the head and adjust

if necessary.

A. Dotate the vertical mill spindle ;0", and set

the dial indicator again.

8. Dotate the spindle #80"and compare the two

readings. 3djust as necessary.

;. -ighten the locing nuts on the swivel head.

#0. Dechec the readings and adjust as necessary.

EO2* -ESC$%BE T)E MO$E COMMON M%LL%N(

MAC)%NE OE$AT%ONS ON A 'E$T%CAL

M%LL%N( MAC)%NE




NOTE< ?hen readings are taen, it is important that the indicator button does not catch in the -$

slots on the table. -o prevent this, it is advisable to wor from the high reading first and then rotate

to the low reading. -he longer the rod used on the dial indicator, the more accurate the setting will

be.

MAC)%N%N( A FLAT S#$FACE

#. Blean the vise and mount the wor securely in the vise, on parallels if necessary.

&. Bhec that the vertical head is square with the table.

(. 'f possible, select a cutter, which will just overlap the edges of the wor. 't will then require

only one cut to machine the surface. 'f the surface to be machined is narrow, an end mill

slightly larger in diameter that the width of the wor should be used. 'f the surface is large

and requires several passes, a shell end mill or suitable fly cutter should be used.

). *et the proper spindle speed for the si:e and type of cutter and material being machined.

+. -ighten the quill clamps.

9. *tart the machine, and adjust the table until the end of the wor is under the edge of the cutter.

A. Daise the table until the wor surface just touches the cutter. Move the wor clear of the

cutter.

8. Daise the table about #>(& inch and tae a trail cut for approximately #>) inch.

;. Move the wor clear of the cutter, stop the cutter, and measure the wor.

#0. Daise the table the desired amount, and loc the nee clamp.

##. Mill the surface to si:e using the automatic feed or hand feed if desired1.

S;#A$%N( O$7 ON A M%LL%N( MAC)%NE

'n order to mill the four sides of a piece of wor so that they are square and parallel, it is

important that each side be milled in a definite order. 't is very important that dirt and burrs be

removed from the wor and vise since they can cause inaccurate wor.



Milling Machine Operationsage 3. o! 3"

Machining Si8e ,

#. Blean the vise thoroughly and remove all burrs from the worpiece.

&. *et the wor in the vise with the first surface *ide #1 facing up.

(. 'nsert a soft metal rod between the wor and the movable jaw if that portion of the wor is

rough or not square.

). -ighten the vise securely.

+. ?ith a soft$faced hammer, tap the worpiece down in the vise until it sits securely.

9. Mount a suitable cutter in the milling machine spindle.

A. *et the machine for the proper speed for the si:e of cutter and the material to be machined.

8. *tart the machine and raise the table until the cutter just touches the right$hand end of side #.



Milling Machine Operationsage 3" o! 3"

;. Move the wor clear of the cutter.

#0. Daise the table about .0(0 in. and machine side # using a steady feed rate.

##. -ae the wor out of the vise and remove all burrs from the edges with a file.

Machining Si8e 2

#&. Blean the vise and wor thoroughly.

#(. lace the wor on the vise with *ide # against the solid jaw of the vise and *ide & up.

#). lace a round bar between *ide ) and the movable jaw, if necessary.

#+. *ecure the worpiece in the vise by tapping with a soft$faced hammer.

#9. Machine *ide &.

#A. Demove the worpiece from the vise and file the burrs from the edges.

Machining Si8e 3

#8. Blean the vise and wor.

#;. lace *ide & facing down with *ide # remaining against the solid jaw of the vise.

&0. lace the round bar between side ) and the movable jaw.

. -ighten the vise securely and tap the worpiece down.

&&. *tart the machine and raise the table until the cutter just touches the right$hand end of *ide (.

&(. Move the wor clear of the cutter and raise the table about .0#0 in.

&). -ae a trial cut, stop the machine, and measure the width of the wor.

&+. Daise the table the required amount and machine *ide ( to the correct width.

&9. Demove the wor and file off all burrs.

Machining Si8e 4

&A. Blean the vise and wor.

&8. lace *ide # down on the vise with *ide ) up.

&;. -ighten the vise.

(0. Machine *ide ) to the correct si:e.




MAC)%N%N( T)E EN-S S;#A$E

-wo common methods are used to square

the ends of the worpieces in a vertical mill. *hort

pieces are generally held vertically in the vise and

are machined with an end mill or flycutter. Hong

pieces are generally held flat in the vise with one

end extending past the end of the vise. -he end

surface is then cut square with an end mill.

Short or= S>aring

#. *et the wor in the center of the vise with one of

the end up and tighten the vise.

&. old a square down firmly on the top and bring

the blade into contact with the side of the wor.

(. -ap the wor until its edge is aligned with theblade of the square.

). -ighten the vise securely and rechec the squareness.

+. -ae about 0.0(0 in. cut and machine the end square.

9. Demove the burrs from the end of the machined surface.

A. Blean the vise and set the machined end on paper feelers in the bottom of the vise.

8. -ighten the vise securely and tap the wor down until the paper feelers are tight.

;. -ae a trial cut from the end to clean up the surface.

#0. Measure the length of the worpiece with a depth micrometer.

##. Daise the table the required amount and machine the wor to length.

MAC)%N%N( AN AN(#LA$ S#$FACE

#. Hayout and mar the angular surface.

&. Blean the vise.

(. 3lign the vise with the direction of feed.

). Mount the wor on parallels in the vise.

+. *wivel the vertical head to the required angle.

9. -ighten the quill clamp.

A. *tart the machine and raise the table until the cutter touches the wor. Barefully raise the

table to set the desired depth of cut.

8. -ae a trial cut for about #>& inch.

;. Bhec the angle with a protractor

#0. 'f the angle is correct, continue the cut.




##. Machine to the required depth, taing several cuts if necessary

Alternate Metho8

3ngles may sometimes be cut by leaving the head in a vertical position and setting the wor

on an angle in the vise. -his will depend on the shape and si:e of the worpiece. *ometimes, a

universal vise can be set to the required angle.

C#TT%N( SLOTS AN- 7E+A+S

*lots and eyseats with one or two blind ends may be cut in shafts more easily on a vertical

milling machine, using a two$ or three$fluted end mill.

#. Hay out the position of the eyseat on the shaft and scribe reference lines on the end of the shaft.

&. *ecure the worpiece in a vise on a parallel. 'f the shaft is long, it may be clamped directly to the

table by placing it in one of the table slots, or on /$blocs

(. Ising the layout lines on the end of the shaft, set up the shaft so that the eyseat layout is in theproper position on the top of the shaft.

). Mount a two$ or three$fluted end mill of a diameter equal to the width of the eyway, in the

milling machine spindle.

NOTE




OO-$#FF 7E+S

Woodruff Keysare used when eying shafts and mating parts. ?oodruff eyseats are more

quicly cut than are square eyseats, and the ey should not require any fitting after the eyseat has

been cut. ?oodruff eys are semicircular in shape and can be purchased in standard si:es designated

by ! numbers1. -hey can also be made from round bar stoc of the required diameter.

Woodruff Keyseat cuttershave shan diameters of

#>& in. for cutters up to ##>& inches in diameter. -he shan

is undercut adjacent to the cutter to permit the cutter to into

the proper depth. -he sides of the cutter are slightly

tapered toward the center to permit clearance while cutting.

Butters over & in. are mounted on an arbor.

-he si:e of the cutter is stamped on the shan. -he

last two digits indicate the nominal diameter in eighths of

an inch. -he digit or digits preceding the last two numbersindicate the nominal width of the cutter in thirty$seconds of

an inch. -hus, a cutter mared 908 would be 8 x #>8 or #

inch in diameter, and 9 x #>(&, or (>#9 in. wide. -he ey would be a semicircular cross section to fit

the groove exactly.

Ctting a oo8r!! 7e6seat

#. 3lign the spindle of the vertical milling machine to ;0".

&. Hay out the position of the eyseat.

(. *et the shaft in the vise of the milling machine or on /$blocs. 2e sure that the shaft is level and

parallel to the table.

). Mount a cutter of the proper si:e in the spindle.+. *tart the cutter and touch the bottom of the cutter to the top of the worpiece. *et the vertical

graduated feed collar to :ero.

9. Move the wor clear of the cutter. Daise the table half of the diameter of the wor plus half the

thicness of the cutter. Hoc the nee at this position.

A. osition the center of the slot with the center of the cutter. Hoc the table in this position.

8. -ouch the revolving cutter to the wor. *et the crossfeed collar to :ero.

;. But the eyseat to the proper depth.

Documents

19591433 Bridgeport Milling Machine Operation Student Handout