BUFFALO ABRASIVES, INC. Disc Manual.pdf · Machine manufacturers provide means of introducing coolant into the grinding zone through nozzles that are directed between the discs and

BUFFALO ABRASIVES, INC. NUT INSERTED DISC MANUAL

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TABLE OF CONTENTS

BACKGROUND ............................................................................................................... 2 MARKET INFORMATION............................................................................................ 3 NUT INSERTED DISC GRINDER OPERATION ....................................................... 4

A) DOUBLE HORIZONTAL SPINDLE - THRU-FEED ............................. 4 B) DOUBLE HORIZONTAL SPINDLE - ROTARY FEED ........................... 5 C) DOUBLE VERTICAL SPINDLE - ROTARY FEED ............................. 5

COOLANTS ...................................................................................................................... 6 A) QUANTITY AND DISTRIBUTION ......................................... 6 B) TEMPERATURE...................................................... 7 C) pH FACTOR ......................................................... 8 D) TYPE & CONCENTRATION ............................................. 9 E) AIR .............................................................. 10 F) RUST CONTROL..................................................... 11

COOLANT SLOTS......................................................................................................... 12 NUT INSERTED DISC MOUNTING & DRILLING INFORMATION .................. 13

A) MOUNTING........................................................ 13 B) DRILLING ......................................................... 14 C) DRILLING - CYLINDER TYPE DISCS ..................................... 15 D) LOCATING HOLES .................................................. 16

18 INCH DISC INSERT LAYOUT............................................................................... 17 23 INCH DISC INSERT LAYOUT............................................................................... 18 26 INCH DISC INSERT LAYOUT............................................................................... 19 30 INCH DISC INSERT LAYOUT............................................................................... 20 DRESSING PROCEDURES.......................................................................................... 21 COMMON DISC GRINDING DIFFICULTIES ......................................................... 22

A) CANNOT HOLD SIZE ................................................. 22 B) CANNOT HOLD PARALLELISM AND FLATNESS ............................ 23 C) CANNOT HOLD SQUARENESS.......................................... 24 D) POOR FINISH....................................................... 25 E) PARTS BURNISHED (FINISH TOO GOOD).................................. 26 F) SCRATCHES ....................................................... 27 G) SWIPES ........................................................... 28 H) BURN (EVERY PIECE) ................................................ 29 I) BURN (PERIODIC).................................................... 30 J) ONE DISC WEARS CONCAVE, ONE DISC CONVEX ........................... 31 K) ONE DISC WEARS FASTER THAN THE OTHER.............................. 32 L) POCKETS OR SCALLOPS DEVELOP ...................................... 33

OPERATING SPEEDS .................................................................................................. 34 SUCCESS REPORTS - NUT INSERTED DISCS....................................................... 35 RECOMMENDED STARTING GRADES FOR NUT INSERTED DISC GRINDING...................................................................................................................... 38


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BACKGROUND

Nut Inserted Disc Wheels are used to generate flat surfaces on a variety of

materials. Disc grinding covers a wide range of applications but is used extensively in

automotive, bearing, foundry, tile (ceramic), tool, knife and spring tolerance work.

The flat surface generated by disc grinding is a much truer flat than that generated

by the periphery of a wheel. If a piece part is to be lapped after grinding, the surface of a

part ground on a conventional surface grinder takes up to ten times longer to lap than a

surface generated by a disc wheel. Producing a flat surface from a flat abrasive has other

distinct advantages. Besides the obvious of grinding two surfaces at the same time, the

two flat surfaces are also parallel. With conventional surface grinders or rotary surface

grinders, where one side of a piece is ground at a time on a magnetic chuck, parallelism

can be maintained but it is more difficult to generate a flat surface. Parts must be

repeatedly turned over in an effort to achieve flatness. When both sides of a part are

ground at the same time, heat is created equally on each side, holding warpage to a

minimum. As the residual strains which would tend to cause warpage are relieved,

warpage is in fact ground out of the piece.

The following pages are intended to provide you with as much detailed

information as possible on Nut Inserted Disc Wheels, their application and operation.


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MARKET INFORMATION

1. MARKET POTENTIAL 5. COMMONLY GROUND MATERIALS ~ Nut inserted Disc wheels ~ Various steels are used throughout industry ~ Cast iron to grind parts of varying ~ Aluminum configurations, flat and ~ Stainless steel parallel ~ Alloys ~ Brass

~ Powdered Metal 2. USERS ~ Ceramics ~ Bearing manufacturers ~ Automotive industry 6. WHEEL COMPOSITION ~ Spring manufacturers ~ Powdered metal parts mfg. ~ Resin Bond ~ Brick and tile mfg ~ Aluminum Oxide abrasive ~ Job shops ~ Silicon Carbide abrasive ~ ALO / SIC combinations ~ Treated abrasive for wet grinding 3. COMMONLY GROUND PARTS ~ Ceramic abrasive ~ Bearing cups, cones & rings ~ Washer type parts 7. MAJOR COMPETITORS ~ Plates ~ Acme ~ Piston rings ~ Anchor ~ Saw blades ~ Bay State, Bendix (Tyrolit) ~ Hand tools ~ Cincinnati Milicron (Tyrolit) ~ Springs ~ Gardner ~ Tile ~ Jowitt & Rogers ~ Norton

~ Pacific ~ Research Abrasives ~ Sterling 4. MOST COMMON DIAMETERS ~ 30" , 26" , 23" , 18"


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NUT INSERTED DISC GRINDER OPERATION

A) DOUBLE HORIZONTAL SPINDLE - THRU-FEED

On this grinder, parts to be ground enter the front of the machine by way of a

chute, pass between the two disc wheels and exit at the rear. Compared to other disc

grinders, "thru-feed" is capable of the highest production rates as work is fed in a

continuous stream through the grinder by means of a feeding mechanism located at the

front of the machine. A variety of feeding methods is available, including roll feed, chain

feed, belt feed and push feed. A pair of guide bars confine the work pieces as they pass

through the grinding zone.

Some double horizontal spindle disc grinders are equipped with an oscillating

fixture mechanism. This type fixture is found in use where production requirements are

not great but extreme accuracy is necessary. A work holding fixture is attached to a

swinging arm and oscillates between the two disc wheels. The fixture then retracts from

its grinding position and the ground part is removed.

In thru-feed grinding, parts to be ground enter the feed mechanism from a chute

by gravity. The feed mechanism usually consists of rubberized, power driven feed belts

which drive the parts between them into the grinding zone. Entrance guides support the

parts vertically and allow for a smooth transfer to the disc wheels.

Exit guides perform the same function as entrance guides except that they allow a

smooth transfer from the disc wheels as the parts leave the grinding zone.

In thru-feed grinding a round part, the horizontal alignment of one or both wheel

heads is changed so that the wheels are tight at the front where the part to be ground first

enters the grinding zone. Round parts are ground with this setup because they are

brought to size as they pass the tightest point between the two discs and then spin and roll

freely as they exit the machine.


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Where other than round parts are to be ground, the horizontal alignment of one or

both wheel heads is opposite the setup for round parts. The heads are set to be tighter at

the exit point, as square or rectangular parts are unable to spin or roll as they pass

through the grinding zone. This setting allows the parts to be progressively ground and

brought to final size just as they exit the grinding zone. If a square or rectangular part

were ground on a machine set to grind round parts, there is a tendency for the parts to tip

between the two grinding discs and become badly marked with grinding swipes.

B) DOUBLE HORIZONTAL SPINDLE - ROTARY FEED

With a rotary feed disc grinder, parts are inserted in the fixture openings at the top

of the machine. The fixture rotates clockwise, carries the parts between the two discs and

exits at the bottom where the parts are removed and dropped into a discharge chute.

C) DOUBLE VERTICAL SPINDLE - ROTARY FEED

With this type grinder, there is a rotary fixture turning in a horizontal plane. The

parts to be ground are inserted at one side of the machine. As the fixture rotates, the parts

are carried between the two discs and exit at the opposite side.

** Rotary fixtures work well for small to medium, irregular shaped parts where high

production rates are a significant factor as this type fixture lends itself to automatic

loading and unloading. A continuously rotating feed mechanism, provided with proper

openings or fixtures, carries the work between the two wheels.


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COOLANTS

A) QUANTITY AND DISTRIBUTION

Clean, cool coolant in large quantities, directed to the proper location, is

necessary for successful disc grinding operations. Coolant problems are magnified in

disc grinding by greater contact areas and greater power input than in a similar operation

done with the periphery of a wheel.

Machine manufacturers provide means of introducing coolant into the grinding

zone through nozzles that are directed between the discs and fittings, to run coolant

through the spindle and through the center hole of the abrasive discs.

Make sure that coolant is cool and that the distribution system is functioning

properly.

As production rates and stock removal increase and the tolerances become tighter,

the control of the coolant becomes more important.


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B) TEMPERATURE

Coolant is ineffective if allowed to become hot. Fifteen (15) degrees over room

temperature should be the absolute maximum allowable increase in coolant temperature.

Large coolant tanks with the minimum of sludge and the maximum of coolant are

important for efficient wet grinding operations. When attempting to maintain close

tolerances, the temperature of the system must be controlled.

Heat causes:

Excessive abrasive breakdown

Poor finish

Poor tolerances

Burning

Distortion

Spindle expansion

Part expansion

Heat is the enemy of precision grinding!


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C) pH FACTOR

Solution strength with regard to acidity or alkalinity is indicated by pH. It is a

measure of the amount, as well as the activity of the acids or alkalis present in the

solution and is represented as a log function of the hydrogen concentration.

Strongly alkaline 13

12 Bond breaks down

11

10

Weakly alkaline 9 Coolant with pH

Neutral 8 6 to 8 recommended

Weakly acidic 7 for Resinoid bond

6

5

4 Machine and parts

3 rust or corrode

2

Strongly acidic 1

This is a logarithmic scale, so each number represents a decimal place. pH nine

(9) is ten (10) times stronger than pH eight (8) and 1/10 as strong as pH ten (10).


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D) TYPE & CONCENTRATION

Soluble oil and emulsion type coolants are purchased as a paste or heavy oil and,

when diluted for use, are milky in appearance. This type of coolant should, when used in

disc grinding, be diluted from 80 to 100 to 1. It will usually have a pH from seven (7) to

eight (8). If this type is used with too high a concentration, it will load and gum up the

abrasive disc and increase the breakdown of the Resinoid bond.

Detergent type coolants come as a lighter oil and, when diluted, are clear. The

concentration of this type coolant should be weaker than 100 to 1 and will have a pH

from six (6) to seven (7).

Another type of coolant comes as a powder and, when diluted or dissolved, is also

clear, but will have a pH of over eight (8). This type is made of sodium nitrite and

sodium carbonate, is very detrimental to Resinoid bond and should be avoided.

Through evaporation, the strengths of coolant will continue to increase. It,

therefore, becomes more of a problem to keep the coolant weak enough, rather than

strong enough. The concentration should be just strong enough to prevent rusting of

parts and machine.


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E) AIR

In dry grinding operations, the only cooling available for control comes from the

air passing over the work as it is being ground. By careful control of the flow of air

through the grinding zone, production rates may be increased, quality improved and

abrasive life increased.

Entering air should be directed to the grinding zone by keeping guards, hoods and

covers tight fitting, so that it flows in the most effective direction. Outside air led to the

grinder can further aid in the dissipation of the heat generated during grinding.

Exhaust fans, fan blades and duct work must be kept at top efficiency and air

filters kept clean.


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F) RUST CONTROL

When ground parts start to rust, the first reaction is to increase the coolant

strength. This usually starts a vicious cycle of increased abrasive wear and parts out of

tolerance, with the subsequent changes in abrasive specification and new trials run.

Rust is caused by low pH, poor coolant control and the depletion of rust inhibitors

from the coolant.

Rust can also be caused by:

1. A slow drying rate. Anything that can be done to

speed the rate of drying will help. Rack the parts,

reduce the tote box loads or move parts to a warm

dry area.

2. Bacterial growth causes the formation of acids in

the coolant solution, which will lower the pH. When

coolant becomes foul, it must be completely changed.

3. Suspension of fine metallic particles in the coolant.

As an example, fine iron oxide is introduced when

grinding rusted parts. When these particles are

deposited on a freshly ground surface, a galvanic

cell is formed, which will start electrolytic

corrosion.


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COOLANT SLOTS

In a thru-feed wet grinding operation, coolant flow through the spindle is

interrupted by the parts as they pass over the center hole. Slots radiating out from the

center hole allow the coolant to pass around the part and help distribute the coolant

across the grinding zone.


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NUT INSERTED DISC MOUNTING & DRILLING INFORMATION

A) MOUNTING

Before mounting a Nut Inserted Disc it should be tapped lightly with a mallet near

the outer edge. A clear sound indicates that the disc is all right. Also at this time, inspect

all inserts for foreign material. Studs should be checked for straightness, soundness and

battered threads. The back of the abrasive disc should be clean and flat.

The steel disc wheels must be clean, flat, free from grinding swarf and burrs.

When mounting abrasives on steel disc wheels, start all of the screws, then center

the abrasives on the steel disc wheels. (Locating holes eliminates the necessity of

centering.) Tighten all screws in each bolt circle together, starting with the inside row.

Inserts should be tightened with from five (5) to ten (10) foot-pounds of torque. The

screws and inserts will stand a lot more but this is all that is needed. A standard allen

wrench should be used to tighten the screws snugly. Do not use long pipes or hammers

with these wrenches as this will distort the metal around the holes in the steel disc wheel.


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B) DRILLING

The American Standards Association has approved hole spacing for the mounting

of abrasive discs on disc grinding machines. This is designated as "A.N.S.I.. Drilling"

and, with a few exceptions, is the standard used.

Disc Diameter A.N.S.I. Drilling

10” 6 on 8” 3 on 4-1/2”

12” 6 on 10-1/2” 3 on 4-3/4”

14” 8 on 12” 4 on 7”

15” & 16” 10 on 12-3/4” 5 on 7-1/2”

18” 10 on 14-3/4” 5 on 11” 5 on 8” 3 on 4”

20” 12 on 17” 6 on 12” 6 on 8” 3 on 4-1/4”

22” & 23” 12 on 20” 6 on 18” 6 on 14” 6 on 8” 3 on 5-1/4”

24” 12 on 22” 6 on 18” 6 on 13” 6 on 8”

26” 14 on 22-1/2” 7 on 16-3/4” 7 on 15” 3 on 4-1/4”

30” 16 on 26-1/2” 12 on 22” 12 on 18” 8 on 11” 3 on 4-1/4”


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C) DRILLING - CYLINDER TYPE DISCS

DISC DIAMETER DRILLING

10" 6 on 9"

11" 6 on 10"

12" 8 on 11"

14" 8 on 12"

16" 8 on 14"

18" 8 on 16"

20" 12 on 18"

22" 12 on 20"

24" 16 on 22"

26" 16 on 24"

28" 16 on 26"

30" 16 on 28"


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D) LOCATING HOLES

Locating holes (sometimes called dowel pin holes) usually consist of a 1/2"

locater and a 9/16" locater in the center of a chord drawn between two inserts on the

outer bolt circle. They are placed diametrically opposite each other.

Positioning the locating holes on a chordal line will give an uneven dimension

between centers of the two locaters, i.e. 25.9906" for the 30" standard. When recording a

locating hole measurement, report the size of the two holes and how they line up with

adjacent inserts.


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18 INCH DISC INSERT LAYOUT

ID Outer Row Next Row Next Row Next Row 0 - 2 10 on 14-3/4 5 on 11 5 on 8 3 on 4

+2 - 6 10 on 14-3/4 5 on 11 5 on 8 +6 - 9 10 on 14-3/4 5 on 11

+9 10 on 14-3/4

14.028"Between Centers

1/2" Locator9/16" Locator


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ID Outer Row Next Row Next Row Next Row Next Row 0 – 3 12 on 20 6 on 18 6 on 14 6 on 8 3 on 5-1/4

+3 – 6 12 on 20 6 on 18 6 on 14 +6 – 12 12 on 20 6 on 18 6 on 14 +12 – 16 12 on 20 6 on 18

+16 12 on 20

Between Centers


19.318"


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ID Outer Row Next Row Next Row Next Row Next Row 0 – 2 14 on 22-1/2 7 on 16-3/4 7 on 15 7 on 8-1/2 3 on 4-1/2

+2 – 6 14 on 22-1/2 7 on 16-3/4 7 on 15 7 on 8-1/2 +6 – 13 14 on 22-1/2 7 on 16-3/4 7 on 15

14 14 on 22-1/2 7 on 16-3/4 +14 14 on 22-1/2

Between Centers

9/16" Locator 1/2" Locator

21.936"


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ID Outer Row Next Row Next Row Next Row Next Row 0 – 2 16 on 26-1/2 12 on 22 12 on 18 8 on 11 3 on 4-/14

+2 – 9 16 on 26-1/2 12 on 22 12 on 18 8 on 11 +9 – 16 16 on 26-1/2 12 on 22 12 on 18 +16 – 20 16 on 26-1/2 12 on 22

+20 16 on 26-1/2


25.990"Between Centers


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DRESSING PROCEDURES

Abrasive discs are dressed in the same manner as wheels, and for similar reasons.

The main difference is that the dresser action changes across the face of the disc. The

surface feet per minute of the abrasive particles decrease from the OD to the ID of the

disc, at a constant RPM. The same dressing action across the abrasive face will remove

more abrasive toward the center of the disc. The dresser will seem to dig into the

abrasive as the center is approached, but actually the lower S.F.P.M. makes the disc act

softer in the center area.

In order to properly dress a nut inserted disc, the dresser arm must be rigidly

mounted and properly aligned with the disc face. Its motion across the face of the disc

must be smooth and continuous.

Discs are dressed for the following reasons:

1. Initial truing of the abrasive face

2. To sharpen the cutting face

3. To re-true the cutting face

4. To increase the latitude of the abrasive disc

Number 4 is of most interest, as by changing the dressing conditions the abrasives

can be made to act coarse or fine, hard or soft, open or dense, but only within reasonable

limits. You cannot compensate for the wrong abrasive, but dressing can be a versatile

tool.


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COMMON DISC GRINDING DIFFICULTIES

A) CANNOT HOLD SIZE

CAUSE CORRECTION Coolant too strong Adjust the coolant strength to below a pH of 9 Coolant too hot Provide larger coolant capacity - clean coolant tanks Excessive stock removal Take more than one pass Feed rate increased Slow down feed rate Abrasives out of flat Re-dress abrasives Abrasives dull Re-dress abrasives, speed up dresser traverse, change to dresser cutters Feed rate not uniform Check feeding mechanism


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B) CANNOT HOLD PARALLELISM AND FLATNESS CAUSE CORRECTION Head setting shifted Re-adjust head alignment Excessive stock removal Increase number of passes Hot coolant Increase supply or chill Feed rate increased or decreased Parts with small stock removal increase feed rate Larger parts slow down feed rate Parts not turning Slow RPM of one spindle if possible Abrasives out of flat Check abrasive position relative to guide plates Check dresser alignment Re-dress abrasives Abrasives dull Check if diamonds are dull Change to dresser cutters if possible Speed up dressing cycle if cutters used Review abrasive specification


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C) CANNOT HOLD SQUARENESS

CAUSE CORRECTION Head setting shifted Re-adjust head alignment Feed stations or guide bars worn Repair feed mechanism Incorrect rotation of abrasives Make certain both discs running same direction - down in front Abrasives out of flat Check abrasive position relative to guide plates Check dresser alignment Re-dress abrasives Abrasives dull Check if diamonds are dull Change to dresser cutters if possible Speed up dressing cycle if cutters used

Review abrasive specification


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D) POOR FINISH

CAUSE CORRECTION Coolant dirty Clean tanks, check filter Coolant too strong Adjust coolant strength to below pH 9 Feed too fast or too slow Slow down or increase feed rate Excessive stock removal Increase number of passes Machine vibration Determine if machine lagged down Check bearings Mount abrasives centrally on plates Balance abrasives Discs dressed rough Check for looseness within dresser assembly Slow down dressing traverse if changing to diamond dresser


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E) PARTS BURNISHED (FINISH TOO GOOD)

CAUSE CORRECTION Feed too slow Increase feed rate Not enough stock removal Leave more stock for final pass Abrasives dull Check if diamonds are dull Change to dresser cutters if possible Speed up dressing cycle if cutters used Review abrasives specification Abrasives loaded Check coolant temperature

and concentration - if too strong, dilute

Increase coolant flow Check for proper coolant distribution Re-dress abrasives Review abrasive specification


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F) SCRATCHES CAUSE CORRECTION Coolant Clean tank, check filter for proper and adequate filtering; Check coolant flow and proper distribution Coolant too strong Adjust coolant strength to below pH 9 Abrasives dressed roughly Check for looseness in dresser assembly Slow down dresser traverse and change to diamond dresser Consider smooth face discs Perforations Review abrasive specification


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G) SWIPES CAUSE CORRECTION Head setting wrong Re-adjust machine Parts not close enough in size Take sizing pass Abrasives out of flat Check dresser alignment Check abrasive position relative to guide plates Re-dress abrasives Entrance or exit guides out of alignment Re-align guides Feed rate not uniform Check feeding mechanism


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H) BURN (EVERY PIECE)

CAUSE CORRECTION Coolant too hot Increase cooling capacity, clean tanks Insufficient coolant Check pump, lines and tank Check distribution of coolant Feed too fast Slow down feed rate Excessive stock removal Take more passes Abrasive speed may be too fast Consider slowing down RPM of abrasives Abrasives dull Check if diamonds are dull Change to dresser cutters if possible Speed up dressing cycle if cutters are used Review abrasive specification


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I) BURN (PERIODIC)

CAUSE CORRECTION Variation in stock removal Take sizing pass Feed not uniform Adjust feed mechanism Interruption in coolant flow Check for restriction within coolant system


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J) ONE DISC WEARS CONCAVE, ONE DISC CONVEX

Once in a while it is reported that one abrasive disc will wear concave, while the

other wears convex. This condition is usually blamed on the disc wheels themselves.

Following are three well defined causes of this condition, along with their correction:

1. The guiding mechanism is out of line with the abrasives

This forces the part into one disc as it enters the grinding zone. Re-align the

guiding or feeding mechanism.

2. Dresser out of alignment

If the discs are not dressed flat, they cannot wear flat.

Re-align the dresser.

3. Parts are heavy compared to the area in contact with abrasive

On vertical spindle grinders, heavy parts will cause more wear on the bottom

disc. The added wear is more pronounced in the center portion of the bottom

disc because of the lower S.F.P.M. As the lower disc becomes concave, the

upper disc will follow and become convex. This can be controlled by more

frequent dressing and/or the use of a harder grade disc on the bottom spindle.


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K) ONE DISC WEARS FASTER THAN THE OTHER

Periodically it is reported that one abrasive disc on a double spindle grinder wears

much more rapidly than the other, even though there is equal stock removal from both

sides of the part ground. This condition is usually attributed to non-uniformity of the two

discs.

Following are three causes of this condition:

1. More vibration in one head than in the other

This can be caused by worn bearings, loose belts, or the abrasive being out of

balance.

2. Belt slippage

A loose belt will allow one head to run slower.

3. Improper in-feeding of the abrasive discs

It is often easier to in-feed one head than the other. Heads must be fed in equally

or alternately!

Suggest that the abrasives be switched, i.e. the right hand disc put on the left hand

spindle and vice-versa. Where uneven wear is reported ask "Has this happened before?"

and "Does the same side always wear faster?"


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L) POCKETS OR SCALLOPS DEVELOP

When grinding a part that is not rigid, such as a coil spring, it is possible to wear a

series of hollows in the face of the abrasive disc. These pockets are round or oval in

shape and are equally spaced around the disc at about the same radius. This development

is a function of the piece being ground and not necessarily the abrasive. It is more likely

to occur when grinding a long run of the same type spring.

As the spring passes through the grinding zone, it is in contact with the abrasive

from the OD to the ID and back to the OD. If the natural frequency of the spring happens

to be close to the speed of the abrasive in RPM, or some harmonic of the speed, the

spring will tend to surge while in the grinding zone. This surge can be triggered by an

inequity in the abrasive or by machine vibration.

When this condition occurs, it may be controlled as follows:

1. More frequent dressing of the abrasive.

2. Change the tilt of the heads slightly to remove stock on a

different area of the abrasive and/or make small change in

spindle speed.


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OPERATING SPEEDS

In spite of the trend to higher operating speeds, 5500 S.F.P.M. is normally the

most efficient speed for disc grinding. In many cases burning or burnishing of the part

may be reduced by lowering the operating speed. 4000 S.F.P.M. to 4500 S.F.P.M. are

usually recommended for hardened pieces with large areas to be ground. A few disc

grinding operations, especially where small areas are involved, are improved by

increasing the speeds to the 6500 - 7000 S.F.P.M. range.

Remember, lowering the S.F.P.M. of an abrasive disc makes it act softer.

Increasing the S.F.P.M. makes it act harder.

In order to figure the surface feet of an abrasive disc, you need to know the

following:

The revolutions per minute of the disc (RPM)

The diameter of the disc in inches (D) Then use this formula - S.F.P.M. = 3.1416 x D x RPM 12

A nut inserted disc does not change in diameter as it wears; therefore, the

S.F.P.M. remains unchanged.


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SUCCESS REPORTS - NUT INSERTED DISCS SIZE: 14 x 2-1/2 usable x 2-5/8 SK.99/69 OPERATION: Double disc grind spring ends COMPETITION: Universal MA20-N-B BUFFALO SPEC: MA202-Q/N-11B2099 COMMENT: "Approved and Re-ordered" SIZE: 26 x 2 usable x 10 SK.114/48 OPERATION: Double disc grind spring ends COMPETITION: Gardner 85A24-K-11BKWCDM BUFFALO SPEC: KJA24-L/K-14BB COMMENT: "Wheels are OK -Do not require dressing as compared to Gardner" SIZE: 14 x 2-1/2 usable x 2-5/8 SK.99/69 OPERATION: Double disc grind spring ends COMPETITION: Gardner 82A24-K/J+-12BKCRDCS BUFFALO SPEC: MA36-L/K-11BB COMMENT: "Finish good-Cutting action good- Establish as source" SIZE: 30 x 3 usable x 16-1/2 SK.58/76 OPERATION: Double disc grind ends of 4140 steel parts COMPETITION: Gardner 87A46-I/G-10BWDCL & Jowitt & Rogers GX46-I/G-ZFH BUFFALO SPEC: KCA46-I-14B4033 COMMENT: "Acceptable product - Will re-order" SIZE: 18 x 4-1/2 usable x 12 SK.264/45 OPERATION: Double disc grind sides of nodular iron connecting rods COMPETITION: Gardner 91A46-G-11BTD3WDCS BUFFALO SPEC: KJA46-G-14B4031 COMMENT: Reported acceptable - Will re-order


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SIZE: 18 x 5-1/2 usable x 12 SK.25/76 OPERATION: Double disc grind 1041 steel connecting rods COMPETITION: Gardner 89A60-I-11BWDCS BUFFALO SPEC: KJA60-J-14B4035 COMMENT: "Finish OK-Cutting action OK-Wheel life and total production better than Gardner" SIZE: 22 x 3 usable x 14-1/2 SK.231/74 OPERATION: Double disc grind 1117 heat treated Universal joints COMPETITION: Gardner 89A80-J-11BW BUFFALO SPEC: KJA803-J-14B4036 COMMENT: "Finish OK-Cutting Action OK-Wheel life and total production better" SIZE: 30 x 2 usable x 10 SK.96/68 OPERATION: Double disc grind powdered metal gears COMPETITION: Bay State (Bendix) C80-Q/O-9B4DNPS BUFFALO SPEC: C80-N-14BB COMMENT: "Good cutting action - Order attached" SIZE: 30 x 2 usable x 1 SK.102/68 OPERATION: Double disc grind powdered metal gears COMPETITION: Research Abrasives SFA80-DCI6BX6575 BUFFALO SPEC: KJA803-I/J-14B4035 COMMENT: "Good finish - Good cutting action" SIZE: 20 x 2 usable x 10 SK.123/51 OPERATION: Double disc grind ends of 52100 rollers COMPETITION: Gardner A120-R13-B2 BUFFALO SPEC: KJA120-Q-14BB COMMENT: Good finish - Good cutting action" SIZE: 23 x 2-1/2 usable x 12 SK.107/78 OPERATION: Disc grind fire clay refractory tubes COMPETITION: Gardner C16-N11-BDCL BUFFALO SPEC: C162-M-14BB COMMENT: "Ground 2880 pieces vs. average of 1750 pieces for Gardner" SIZE: 30 x 3 usable x 10 SK.214/68 OPERATION: Double disc grind fired tile


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COMPETITION: Gardner C20-H-10BL13DCL BUFFALO SPEC: C242-I-14BB COMMENT: "Wheel life and grinding productivity equal to Gardner - very smooth finish, very little chipping, almost no scrap" SIZE: 18 x 3 usable x 10 SK.10/49 OPERATION: Double disc grind Berylluim copper panels COMPETITION: Jowitt & Rogers W60-EZ BUFFALO SPEC: KCA80-E-14B4032 COMMENT: "Cutting action and finish excellent 3000 pieces ground vs. 600 for J. & R." SIZE: 23 x 2 usable x 12 SK.141/69 OPERATION: Double disc grind various hi-strength alloys COMPETITION: Bay State(Bendix) FWA60-I/H-13B4D BUFFALO SPEC: KJA46-I-14B4033 COMMENT: "Good finish - Good cutting action" SIZE: 30 x 2 usable x 16 SK.164/83 OPERATION: Double disc grind ductile iron gun cases COMPETITION: Gardner 82ASC60-H-12B103DCS BUFFALO SPEC: KCA60-F-14B4033 COMMENT: "Very good finish - Very good cutting action"


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RECOMMENDED STARTING GRADES FOR NUT INSERTED DISC GRINDING

MATERIAL STARTING SPECIFICATION

Alnico KJA60-H-14B4033 Aluminum / Soft

Rough Finish

C242-J-14BB KC603-J-14B4036

Aluminum / Hard Rough Finish

KJA36-I-14B4032 KJA803-J-14B4035

Bearing Races Soft State Hard State

KJA46-J-14B4034 KJA603-H-14B4033

Brake Lining Rough Finish

C162-M-14BB KC46-K-14B4037

Brass Rough Finish

C242-J-14BB KCJA100-J-14B4036

Bronze Rough Finish

C242-J-14BB KCJA100-J-14B4036

Carbon Snag Rough Finish

C16-K-14BB KC36-J-14B4035 KC80-H-14B14B4034

Cast Iron Castings C162-J-14BB Connecting Rods / Nodular Iron KJA36-H-14B4031 Copper KC36-I-14B4034 Dies / Hardened KJA46-G-14B4031 Forgings MA162-K-14BB Gears / Hardened KJA36-I-14B4032 Knives

Rough Semi

KJA46-H-14B4032 KJA60-H-14B4033

Magnesium KC803-H-14B4034 Malleable Castings MA20-K-14BB Piston Pins KJA60-I-14B4034 Piston Rings

Rough Semi Finish

C242-K-14BB KC46-I-14B4035 KC80-G-14B4033


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MATERIAL STARTING

SPECIFICATION Roller Ends KJA803-J-14B4036 Springs

Ferrous / Small Gage Ferrous / Medium-Large Gage Non Ferrous

KJA36-K-14B4036 MA24-K-11B2099 KC46-J-14B4036

Steel Castings / Hardened Rough Finish

MA24-I-14BB KJA46-H-14B4032

Stove Parts / Cast Iron C162-J-14BB Tile C242-H-14BB Wrenches

Rough Finish

MA20-J-14BB KJA120-J-14B4035

Documents

BUFFALO ABRASIVES, INC. Disc Manual.pdf · Machine manufacturers provide means of introducing coolant into the grinding zone through nozzles that are directed between the discs and