Paper and Pulp Mill










C O N N .


SIX years ago ball bearings on paper making machinery were first introduced in America.
Today ball bearings are in use on practically every type of machine found in pulp and paper mills.

In the paper industry S K F was the pioneer ball bearing; today all others are judged by it. Its success has been marked; in fact S K F is the standard on many machines today.

This book is written with a view to showing the numerous purposes for which S K Fis now used in the pulp and paper industry. It is intended to show pulp and paper mills the advantages of machines S K F equipped.

Copyright, 1920, by






AS long as machinery has been in existence, there have been bearings to lubricate. The problem of bearing lubrication is, therefore, the oldest of all lubricating problems.
Until comparatively recent years bearings were crudely designed and low-speed conditions prevailed.

The lubricants employed were vegetable oils, such as olive, rapeseed and castor oils; animal fats and oils, such as tallow and lard oil, sperm and whale oil.

The enormous industrial development that has taken place in the last half century has brought into existence engines and machinery of all kinds embodying greater efficiency in operation. There are today a variety of bearings operating under higher speeds, higher pressures and higher temperatures than have been known at any previous time in the world’s history.

Lubricating oils have, of necessity, undergone a similar great development, made possible only by the discovery and use of mineral lubricating oils manufactured from a variety of petroleum crudes found in many parts of the world.

The important factors in bearing lubrication become apparent when the subject is divided into its fundamentals.

Therefore, we treat, in successive chapters- the construction of bearings; the conditions under which they operate; the various systems by which oil is applied; the principles of lubrication ; the treatment of frictiona l heat; the manufacture, physical properties and selection of oils; the properties and use of grease ; typical bearing troubles with their remedies; and the atta inment of true economy in bearing lubrication by the use of the correct high-grade lubricants in the right way.


A bearing is a support for a revolving shaft or the like. The bearing is usually composed of the following parts: the brasses-bearing pieces or steps (usually made of brass or of cast iron surfaced with anti-friction metal commonly known as babbitt) which surround the journal or bearing surface of the shaft; the block, pedestal or frame supporting and enclosing the brasses; and the keep or cap which secures the whole together by means of bolts or studs.


There are five main types of bearings, as

follows Solid bearings,
Two-part bearings,
Four-part bearings,
Thrust bearings,
Ball and roller bearings.


In all solid bearings, the shaft or bearing can only be removed from endways, and the bearings cannot be adjusted when worn. To provide for ready examination or adjustment the two-part or four-part Fig. 1- spindles used in textile mills.bearings are built up around the shaft.
Solid Bearings (Fig. 1) are used to support the vertical high-speed ring
Solid Bearings or bushings are all ring spindle ways small in size. They are bearings used for loose pulleys and small shafts, and in a variety of machinery, such as cranes, and hoisting machinery. They are also used as piston-pin bearings in the great majority of internal combustion engines.



A bushing or sleeve (A- Fig. 2) is frequently provideJ so that when the bushing is worn it can be replaced .


(Figs. 3, 4 and 5)

The majority of bearings are of this type. In the two-part bearings made in halves, usually of cast iron surfaced with babbitt metal.

Fig 2 Solid bearings and bushing

Fig. 3 illustrates a two-part bearing for the crank pin of connecting rod end. A and B are the bearing brasses shown in two parts.

Fig 3 Connecting rod and bearing

Fig. 4 illustrates a two-part bearing used for larger journals. Between the top and the bottom halves are placed liners, thin strips of metal. When the bearing wears, one or more of these strips may be removed, so as to bring the two bearing brasses closer together around the shaft.

Fig 4 Large two-part journal bearing

Fig. 5 illustrates a two-part bearing used for small and medium size line shafting. These bearings are usually lined with babbitt metal but are sometimes made of brass.

The two-part bearing is not suitable where the pressure on the journal is directed against the joint of two bearing halves. Large, bearings operating under such conditions are, therefore, frequently designed as four-part bearings.


These bearings are used principally as main bearings in large horizontal steam

engines and gas engines.

The brasses are built up in four parts.

Side wear is taken up by turning vertical adjusting screws (A) thus moving the vertical wedge (B) which pushes the bearing brasses closer around the shaft. Vertical wear is taken up in a similar manner by adjustment of screw © which moves the horizontal wedge

Fig 5 Shaft hanger


Thrust bearings are designed to counteract pressure in the direction of the shaft and so keep the shaft in its correct position while supporting the load in vertical units or acting against the thrust forces in horizontal units.
Thrust bearings are extensively used in hydro-electric units, steam turbines, for ship propulsion, for centrifugal pumps, etc.

Fig. 6 illustrates the principle of a plain foot-step bearing designed to support the vertical shaft of a steam turbine.

It consists of a housing (F) holding in position in the guide bearing (G) which, in turn, holds holds in position the vertical shaft (A) supported at the bottom by foot-step (H).

The footstep (H) may be adjusted in position by means of support and adjusting screws (D and C).

Oil is forced at high pressure between the footstep (H) and the bottom of the vertical shaft (A) through drilled passageways (J). The entire weight of the vertical shaft (A) is thus borne by the thin lubricating oil film. After lubricating the foot-step bearing, the oil passes upward around the shaft (A) supplying lubrication to the guide bearing (G). The oil then overflows and leaves the bearing through passage (K) in the housing (F).
In order to prevent condensed steam from the turbine from running down the shaft and mixing with the oil, a collar (L) is provided, which throws the water into a chamber (M) from which it is drained through passages (O) in the housing (F).


SIX years ago ball bearings on paper making machinery were first introduced in America.
Today ball bearings are in use on practically every type of machine found in pulp and paper mills.
In the paper industry S K F was the pioneer ball bearing; today all others are judged by it. Its success has been marked; in fact S K F is the standard on many machines today.
This book is written with a view to showing the numerous purposes for which S K Fis now used in the pulp and paper industry. It is intended to show pulp and paper mills the advantages of machines S K F equipped.
S K F- the reliable bearing
IN a continuous process like paper making it is absolutely necessary to have reliable bearings. A bearing failure in any of the machines means a shutdown with huge waste · and the delay and trouble of starting up again.
S K F have been proven reliable in actual service. Not only have they proven far more reliable than any other type of bearing, but also more economical to use. In considering the change which has taken place in substituting ball bearings for plain bearings on paper machinery, the question that naturally suggests itself is, “Why has it been advisable to make these changes ?” The fact that the changes are going on constantly is evident, but. the reason is sometimes lost sight of.
The primary reason is that ball bearings solve the lubrication problem always present with plain bearings. The successful operation of plain bearings depends upon the maintenance of a perfect film of oil between the shaft and the bearing lining. When this oil film is broken, the metal surfaces of the shaft and bearing lining come in contact, and friction, heat and wear result. Two metals in rubbing contact must always produce this result. The greater the pressure between the rubbing surfaces, of course, the greater the friction.
Contrasted with this condition, ball bearings do not depend upon a film of oil to keep the bearing surfaces apart. This may seem paradoxical, as it is well known that ball bearings must be lubricated. But the main purpose of the lubricant is to preserve the highly finished surfaces of the balls and races. The life of a ball bea ring is dependent upon such protection.


The difference between the action of plain bearings and ball bearings is further illustrated by the curve below. This curve shows the maximum load that can be carried by a plain bearing at any given speed if the oil film is to remain unbroken. Should either the pressure or the velocity exceed the limit as shown on this curve the qil film would break. Wear of the bearing would result. The action of the ball bearing however does not depend on the satisfactory maintenance of an oil film.
The internal action of a ball bearing is different from that of a plain bearing. The surfaces are in rolling contact instead of rubbing contact. Compare the effort required to roll a ball on a smooth surface and that required to push one flat surface over another. The lowest coefficient of friction of well lubricated plain bearings is about .025. S K F Ball Bearings have a coefficient of friction, independent of speed within wide limits, of approximately .003 . As an ill ustration of this a nest of dryers that requires 50 horse power to overcome the friction of

well lubricated plain bearings would require 5° X .OO3 = 6 horsepower to operate when mounted on S K F Ball Bearings. To this fifty horsepower we must add the enormous starting effort due to the setting of plain bearings. Ball bearings have no such additional load. To start ball bearing dryers requires no greater effort than to keep them running. This is one explanation of why SKF Ball Bearings have been used on paper making machinery.

The Construction of S K F
The SKF Radial Ball Bearing consists of an outer ball race, an inner ball race, two rows of balls, and a retainer. The S K F inner race contains two grooves in which the balls travel. These grooves are ground to a radius slightly larger than the radius of the balls. The inner surface of the outer race is spherically g:ound -so that all points on this surface are equal distance from the center of rotation of the bearing. Inner race, balls and retainer are free to turn in any position in the outer race. This is the S K F feature of self-alignment possessed by no other bearing. It absolutely prevents binding due to bending of the shaft or slight errors in machining. The two rows of balls are held and spaced by a retainer. The S K F retainer has no rivets screws or other devices which can become loose. To take thrust there is the S K F Thrust Bearing. This is made in a number of types – single or double thrust with flat seat, single or double thrust with aligning seat and t he self-contained self-aligning double thrust bearing, another exclusive S K F feature.




Care of S K F
Many people believe ball bearings are delicate and require a great deal of care. This is not so. S K F Ball Bearings are much more rugged and require less attention than plain bearings. However, ball bearings are a different type of bearing and therefore require different care.
In the first place water must be excluded from ball bearings. To do this our Engineering Staff has developed S K F waterproof housings. This has been done with the co-operation of various prominent builders of paper and pulp mill machinery. These housings represent our approved design and will exclude water perfectly.
The second point to remember is lubrication. S K F Ball Bearings do not need to be lubricated nearly as often as plain bearings because their housings are oil tight. The oil cannot leak out. Experience has shown that S K F Ball Bearings use about one-tenth as much lubricant as plain bearings; this lubricant should be given them once every 9 to 12 weeks.
The lubricant used should be only the best oil or grease and should be neutral. That is, it must contain no free acid or alkali either originally or thru deterioration.
When renewing lubricant, the bearing and housing should first be thoroughly cleaned with gasoline or kerosene. The new lubricant . should then be filled into the housing; do not allow the bearing to be without lubricant even when it is not running:

Due to the unusually heavy service and frequent neglect that barkers must stand it is of first importance to have them as rugged and foolproof as possible. The S K F Ball Bearing saves both trouble and attention. Made of the very finest steel it is practically proof against wear.
Barkers equipped with S K F are free from delay due to hot bearings. There can be no trouble due to oil leaking out and leaving the bearing dry. S K F Ball Bearings are surrounded by a large chamber which holds enough lubricant for several months.
Another feature of S K F equipped barkers is that they save power. The friction of plain bearings is eliminated.
In the disc type of barker the S K F Ball Bearings are located in the main journal boxes. of the shaft carrying the disc.
In the drum type barker S K F Ball Bearings should be in the carrier rolls supporting the drum.


Pulp Grinders

The bearings of a pulp grinder are worthy of careful attention by designers. Makers who use plain bearings mount them in so-called self-aligning boxes and provide water cooling to reduce heating. Very often wood is used as the bearing lining because plain bearings wear so rapidly and wood is easier to replace. Every attention is given to repair after wear, but seemingly little time has been spent in finding the proper bearing-one which will resist wear and therefore avoid all the trouble now so common.

The S K F Ball Bearing is such a bearing. Its races and balls of hardened high carbon chrome steel do not wear. The rolling of the balls on the races prevents friction and heating; and the lubricant constantly circulates as the bearing revolves.


“We are pleased to advise we first tried a set of your S K F Ball Bearings on one of the cylinder molds on our Black-Clawson machine and the bearings pleased us so well, we immediately decided to similarly equip the remaining three cylinders. We have found that these bearings have increased the life of the felts on this machine fully 50%, to say nothing of the annoyance caused by the felts bothering us before the bearings were installed. There is also a considerable saving in power, which we have not attempted to estimate. We might add that since equipping the cylinder molds, we have installed your bearings on one suction roll and one baby press roll, and expect in the future to put them on more of the press rolls on this machine. ” When the writer asked our superintendent today what he thought of these bearings, he replied, ‘ I cannot say enough for them.’
“We are very glad indeed to give you the benefit of our experience, and with kind regards, we are”
Carthage Sulfite Pulp & Paper Company (Signed) Guv C. JONES, Sec’ y.


By using special pillow blocks with the proper S K F Bearings results can be obtained far beyond any given by the plain bearing. First S K F Ball Bearings eliminate the frequent replacements of the bearing lining. Second, they provide a bearing that is self aligning in itself without the use of any self-aligning box or other device. Third, S K F Ball Bearings will save a large part of the power wasted by plain bearings. Fourth, they will show a marked increase in production.


Wet Machines

S K F Ball Bearings have proved by actual dollars saved that they can be used to great advantage on wet machines. Cylinder mold and couch roll are turned by the pull of the felt alone. When they are mounted on plain bearings the pull on the felt is far too great. The unnecessary friction-due to the plain bearings puts a heavy extra load on the felt and this tends to pull the felt apart and produce wear. Felts wear out long before they should. The same is true of the cylinder mold wire face.
There is no reason why both felt and wire face cloth should not last twice as long as they ordinarily do. The felts on S K F equipped machines do S K F Bearings eliminate all the needless friction and so remove all unnecessary strain from the felts. The cylinder molds also last much longer when the bearings are S K F. When the couch roll is raised the force of the water from the shower pipes is enough to turn an S K F equipped cylinder mold. This shows how easy running they are.
Power saving is another feature not to be overlooked in S K F equipped wet machines. It certainly is useless to waste power when by using S K F Ball Bearings it can be saved. Users have found that the power saving made by S K F shows up as a money saving at the coal pile.


The Winestock De-Fibering and De-Inking Machine

This machine has been arousing great interest in the paper trade. It is designed to remove ink and color from waste paper, at the same time defibering the paper. It separates ink from fiber and ensures a brighter pulp. This machine is S K F equipped. We give here the reason why it is S K F equipped-the reason of Castle, Gottheil and Overton, who sell the machine and for whom it is built.
They say: “We decided to use your bearings upon the recommendation of Messrs. E. D. Jones and Sons Co., Pittsfield, Mass., who built the machines for us, and we realized the necessity of having the most reliable bearings we could get. The shaft whereon we · use your bearings runs at a speed ranging from 1800 to 2300 r.p.m. and as the propellers on the shaft are the means by which we break up into fiber the waste papers there is considerable strain on the shaft and bearings, especially during the loading process. Thus far we have· obtained excellent results from your bearings and are using the same in all machines we are building. “We understand that you guarantee the bearings to do the work required of them provided they are installed in accordance with your specifications, and we therefore feel we are taking no risk in adopting your bearings for our machine where a reliable bearing is absolutely essential. to the successful operation of the machine.”- Frank C. Overton.

The success of this machine has been phenomenal and S K F has played its part. By eliminating all worry that plain bearings would give, S K F has helped materially. The S K F 1700 series self-contained, self-aligning double thrust bearing is used in combination with the S K F self-aligning radial bearing. The success and satisfaction obtained with both types of bearings proves that S K F Ball Bearings, both radial and thrust, are excellently suited to this severe and continuous service.


Jordan Engines

Jordan engines with their high speeds and heavy power consumption have afforded a good opportunity to prove the value of S K F Ball Bearings. After a number of years of service both users and manufacturers report results that are extremely satisfactory. Tests show the advantages of S K F equipped Jordans over the old style Jordan with plain or babbitted bearings.
Plain bearing Jordans use about 30% more power than S K F equipped Jordans. At the same time S K F equipped Jordans run about 40% faster. Results have shown that a great increase can be made in the stock fed to S K F equipped Jordans. S K F Ball Bearings hold the plug absolutely in the center of the shell. There is no wear, no dropping of the plug; and this naturally means a very uniform stock of great fineness. In plain bearing Jordans the bearing wear allows the plug to drop and the result is often poor stock. S K F eliminates this. S K F Thrust Bearings have proven their worth both in new Jordans and as a replacement for worn thrusts in old Jordans. The fact that they are of hardened steel prevents the wear so common in bronze thrust bearings.· The Dillon Machine Company, of Lawrence, Mass., makes a specialty of replacing bronze thrust bearings with a special design using S K F Thrust Bearings. The satisfactory results obtained make this well worthy of your investigation.




This section deals only with the Fourdrinier part. Press rolls, dryers and so on, will be taken up later under their respective headings.
The application of S K F to Fourdriniers has met with unqualified success. By mounting breast rolls, table rolls, wire rolls, and couch rolls on S K F Ball Bearings two great things have been accomplished. First an enormous amount of friction has been eliminated and power saved. Second, the greater part of the wear on the wire has been eliminated.|
We must bear in mind that table rolls and wire rolls are turned by the pull of the wire only. If these rolls have the least tendency to stick there is a heavy drag on the wire and of course the result is wear and wasted power. By equipping these rolls with S K F Ball Bearings they become so easy running that the merest touch will turn them. It is clear that by replacing the old type plain bearing with the modern S K F Ball Bearing, friction and wear on the wire -are eliminated as far as they can possibly be.


A test run with table rolls for a 202-inch Fourdrinier news machine showed some surprising results. A table roll for this machine mounted on S K F took only one ounce, tied to a string and wrapped around the roll, to make it turn. A similar table roll mounted on plain bearings needed seven times this weight before it moved.
Flat spots on table rolls are the result of stiff, binding plain bearings. If such rolls are used they either revolve with a jerky motion or they do not revolve at all.. Such irregular motion disturbs the stock as it forms on the wire, and frequently causes the stock to spatter. This results in imperfections, causing the paper to tear and necessitating the stopping of the entire machine from Fourdrinier to winders.
Further great advantages are gained by mounting the breast roll and couch rolls on S K F. First there is a· very considerable power saving. Then, there is no wear. S K F Ball Bearings, since they are of finest hardened steel, do not wear or drop out of alignment.


It is important to have breast roll and under couch roll revolve at the same speed, so there is no pull on the wire. For this reason S K F Ball Bearings are ideal because they permit the rolls to revolve with absolute freedom. This greatly increases the life of the wire. It must be remembered. that S K F Ball Bearings are mounted in a waterproof housing. These housings are designed in what long practice has shown to be the ·best way. The experience of users, of manufacturers and of the S K F engineers has contributed to. perfect the S K F housings used oh paper making machinery.
By means of grease grooves, felt grooves and flingers water is· kept away from the bearing. We cannot impress the user of ball bearings too much with the harm water will do to a high grade bearing like S K F. Water can and does harm a ball bearing. The chemical action of water on steel must be avoided. Just as water slowly destroys wood, so will it also destroy the finest steel. Quality bearings must ·be protected from water.
This can be done easily and positively by the S K F housing. It keeps water out and oil in. It protects the bearing from injury and keeps it always supplied with lubricant. The result is a bearing which needs no attention, beyond an occasional oiling and which will give no trouble unless used as it should not be.
Since the Fourdrinier is used for making thin, high grade paper, every step should be taken to help make its operation perfect. S K F hold the parts they carry in accurate adjustment and when the rolls. They are once properly set it is not necessary to worry about wear or poor adjustment. S K F eliminate both.


The Cylinder Machine

The results obtained by equipping the cylinder molds and couch rolls of a cylinder machine with . S K F are very much the same as those obtained in a wet machine. Users have found that the life of the felt is greatly increased; 50% added to the life of felts

through S K F Ball Bearings is not unusual. Felts are expensive; by investing a small sum in S K F Ball Bearings users have profited may times this amount by saving in felts alone.
The power saved by eliminating useless bearing friction is another large item which makes S K F a dividend paying investment. Many letters have been


sent us saying that, though no tests had been run, greatly reduced power bills or coal bills proved that S K F made a large saving in power.
Naturally by eliminating needless friction the drag on the cylinder mold is greatly reduced and a corresponding saving is made. The wire face is not subjected to needless pulls to make it turn. Wear is reduced to the minimum and consequently the life of the cylinder mold is lengthened.
The felt return drum is another place where S K F have been successfully employed. This roll takes the entire pull of the felt and relieves the couch rolls of unnecessary strains. It must be easy turning and respond to every pull so that no power is wasted and no extra wear placed on the felt. That is why it is mounted on SKF.


Squeeze rolls are subjected to heavy pressure and the bearings are exposed to water unless properly protected. Here is a logical place for S K F. With its high load carrying capacity and its oil tight waterproof housing the S K F Ball Bearing will eliminate wear and wasted power at this point. By providing an easy turning roll, one which can be quickly removed and which is free from bearing trouble, squeeze rolls can be greatly improved.
” We have used your S K F Ball Bearings, both the heavy and light types, on several parts of paper making equipment with excellent results. We have found that in the two or three instances where trouble has occurred, this trouble was always due to neglect, especially when it came to lubricating. “We have made some installations which have been in service over two years.” UNION MACHINE CO.


Press Rolls

A bearing for press roll work must be housed waterproof and must also be able to withstand heavy pressure. S K F Ball Bearings have these features. On both press rolls and primary or baby press rolls S K F has shown excellent results.
The steel used in S K F Ball Bearings can stand tremendous loads. A single ball made of this material one inch in diameter will stand a load of over fifty tons before breaking. So it is plain that S K F Bearings are ideal for heavy loads.
On upper press rolls S K F give particularly good service. These rolls must turn freely so that the sheet may pass through evenly over its full width. When plain bearings are used one bearing always takes more power than the other, causing the paper to lag on one side. When S K F Ball Bearings are used these rolls turn with perfect freedom and there is no drag or lag. The waterproof feature, combined with reduced bearing friction and elimination of lubrication troubles, gives paper manufacturers means of increasing the life of the felt, improving the quality of the paper and saving power.

Dryer Rolls

The service on dryer rolls is unusually heavy. Due to the great weight of the dryers it was long supposed that the plain bearing was the only bearing which could stand the work. This theory, however, has been exploded.
One of the largest paper mills in the East has equipped some dryer cylinders with S K F Ball Bearings. These have been in operation since early in 1916 with the most satisfactory results.
The dryer rolls each weigh 22 tons and the diameter of the journal is over 7 inches. Each cylinder is carried by two S K F Ball Bearings. The power necessary to run these cylinders is greatly reduced and the reduction on starting load is even greater. It is clear


that the plain bearings on a battery of dryers will easily be squeezed dry and make starting loads abnormally high.
Furthermore the fact that the dryer cans are filled with steam makes it exceedingly difficult to tell when a plain bearing is heating due to being dry. S K F Ball Bearings eliminate this trouble. They are specially fitted to allow for high steam temperatures.
No trouble is possible and none can occur when mounting and care are right. Continuous lubrication and continuous service are assured.
In addition to the large dryer rolls S K F Ball Bearings have also been applied to felt dryers, with signal success. One company has found that by equipping their felt dryers with S K F they can use a felt six months where formerly it lasted only two to
two and a half months. In addition, no auxiliary drive is necessary because the rolls are so easy turning. The rolls turn by the pull of the felt alone.
A calender dryer was made by one of the leading builders of paper making machinery and was equipped with S K F Ball Bearings. The weight of these rolls was 50,000 pounds each and the arrangement was such that the load per set of bearings was 100,000 pounds, 50 tons. This load was carried by a pair of S K F No. 1446, bore a little over 9 inches. The rolls were heated by steam at 18 lbs. pressure and allowance had to be made for this.
The results of this test were exceedingly satisfactory. The calender dryer which consisted of two of these huge rolls was run by about 1O horse power. The rolls were so free-running that a mere push of the hands was enough to start the one roll when released from contact with the other.
It was conclusively proven that S K F Ball Bearings give remarkable results even under such trying conditions of load and temperature as were met with in this calender dryer.
“For the past five years we have used S K F Ball Bearings· on our Paper Machines with very satisfactory results.
“Enclosed in their Waterproof Housings we consider them particularly adapted for Cylinder Molds. In t his connection they have proven great savers of felts as well as materially reducing the power consumed.
“S K F Ball Bearings always have our recommendation for this class of work.”
(Signed) EDW. T. MCNALLY, Manager.



A desirable place for the application of ball bearings is on the intermediate rolls of calenders. The bearings of these rolls must be exceedingly accurate to hold the axes of all rolls exactly parallel. This is to prevent calender cuts.
Where the load is not excessive .one bearing is used on each end of the roll. This. makes a mounting that is self-aligning in itself and makes parallel adjustment of rolls easy. Where the loads are too great for a single bearing two bearings are used in each housing. The housing then must be of the aligning type.

The enormous pressure on calender rolls will squeeze out all lubricant and wear the best babbitt or bronze. When SKF are used on the intermediate rolls, rubbing is eliminated and the rolls can always be held absolutely in the desired position. When S K F equipped intermediate rolls are removed, the housing, bearing and lubricant come with them. So the bearing need never be disturbed on the shaft and it will always be protected by oil even when the roll is dismounted.

Winders, Slitters and Rewinders

It is well to have these machines as easy running as possible to avoid all unnecessary power waste. S K F Ball Bearings will do this by removing the friction of plain bearings.

In addition S K F Ball Bearings need very little attention – only a replenishing of lubricant once every three or four months.

In winders and rewinders the weight of the stock as it is reeled up will often cause the winding shafts to deflect or spring. This deflection may be only very slight, but no shaft is so rigid that it will not deflect


under heavy load. This will cause the shaft to bind if carried on plain bearings and naturally the bearing will score and wear.

S K F Ball Bearings, on the other hand, will carry such a shaft perfectly because they are self-aligning and compensate for the bending and springing of the shaft.

On slitter cutters, S K F prevent the sticking of the circular cutter by providing a free-turning, nonbinding bearing. Plain bearings in cutters will heat and bind. This dulls the cutter rapidly and prevents a smooth clean cut.

The improvement S K F will make on this type of machinery is not to be underestimated.
“We have used the S K F Ball Bearing for a number of years with very satisfactory results. The Cameron Slitter must be free-running and durable as well as free from wear and trouble. In order to obtain this, we have equipped each Cameron Cutter with an S K F Ball Bearing and have found that this self-aligning ball bearing meets our requirements in every respect.

“The quality of the Cameron Slitting and Rewinding Machine demands that every part entering into its construction must be of the highest quality. In the S K F we have found a bearing which fulfills these requirements.”
(Signed) JAMES A. CAMERON, President.


“We have used a good many thousands of dollars worth of your S K F Ball Bearings on the paper making machinery that we manufacture, and the results that this type of bearing have given, have been-in the main-very satisfactory.
“We believe that these S K F Bearings are particularly desirable on felt dryers, thereby enabling the dryers to be readily driven by the felt alone without the use of any gear, and these bearings have also been used by us with entire satisfaction on many other units of a paper making machine, such as: couch-rolls on cylinder machines, cylinder molds, wire-carrying rolls and other rolls that are not power driven.

“We believe that our Company was the first paper machinery manufacturing concern that ever used any of your S K F Ball Bearings, and we anticipate using them in considerable quantities on our paper machinery in the time to come, wherever it is possible to do so.”

(Signed) GEORGE S. BARTON, Treas.

“We are using SKF Ball Bearings on six cylinders and drum roll on our board machine and on one cylinder and drum roll on our sulphite machine. We find that they are giving excellent service and that the life of our felts is greatly increased by their use.

“We do not know what saving we make in power, but are sure that this is considerable, as the increased length of the life of out felts would show.
“We are very glad to be able to testify to the excellence of your product.”

(Signed) J. H. THICKENS, Manager.


Motors in paper mills are very generally left to take care of themselves. The current is turned on; the motors run; nobody pays any attention to them until a hot box compels it. Then there is a shutdown, followed by expensive repair work and costly delay. All this can be very easily avoided by the use of S K F Ball Bearings. They take care of the two points vital to motor life. The first is lubrication; the second is freedom from wear.

S K F Ball Bearings are housed oil tight. No oil can leak out and therefore a supply of oil will last months in a ball bearing motor. It is only necessary to lubricate S K F equipped motors once every four to six months.

The very finest steel obtainable plus painstaking care in heat treating and grinding make S K F Ball Bearings the most efficient guardians against wear that can be used on any motor. Several large motor manufacturers have standardized on S K F and use only SKF on all their motors. Other manufacturers have standardized on S K F for certain types of their motors, and every manufacturer can furnish S K F equipped motors if specified.

All motors in paper or pulp mills need S K F on account of the heavy work required of them.

Our special catalog on motors goes further into this subject.


Pumps and Auxiliaries
There are certain auxiliaries used in paper and pulp mills which are also used in other fields and on which S K F have been thoroughly proven. One of these is the electric motor which has just been described. Another is the centrifugal pump.

The main trouble of this type of pump is bearing heating and wear. Naturally where there is heating there is also a large power loss. These troubles are eliminated by the use of S K F Radial and S K F Thrust Bearings.

Many makers of fans and blowers, among them the largest in the country, have long been equipping their product with S K F.

Trucks, hoists, trolleys, cranes and all other auxiliary equipment can be . bought S K F equipped. Various manufacturers of such machinery have so designed their product. And it is a significant fact that in each instance these makers who use S K F are the acknowledged leaders in their field. We have complete literature and information on a large variety of subjects. This will be sent you on request.

S K F Transmission equipment is the S.K F Self-Aligning Ball Bearing adapted to transmission work. The hole in the inner race of the bearing is tapered. In mounting the bearing on a lineshaft a tapered · split sleeve is first slipped on the shaft; then the bearing is slid into place on this sleeve. A locknut forces the bearing tightly on the sleeve and holds the sleeve firmly to the shaft. In this way no machining of the shaft is necessary:

S K F Ball Bearings are a great step in advance of any other bearings used on paper mill drives. They are extremely durable and economical. They use only 20% of the lubricant used by plain bearings. In addition they save from 60 to 80% of the power wasted in friction by babbitted bearings.

S K F Ball Bearings are supplied with an oil tight dustproof housing that can be mounted in drop hangers, post hangers or pedestal pillow blocks. They are also supplied in rigid solid or rigid split pillow blocks ‘where the base and housing are a complete, rigid unit. For use in paper mills S K F Transmission equipment presents many advantages. Shafting, no matter how carefully put up, will in time pull out of line. Heavy loads, vibration, and settling of buildings will do this. The shaft will not be out of line enough to be noticeable to the eye; but even the least bit is enough to bind a plain bearing. This is just what S K F Ball Bearings prevent. They are self-aligning and they compensate for misalignment. Even if the shafting is out of line it will run just as freely as ever when it is


carried by S K F Ball Bearings. Misalignment cannot bind an SKF.

Then too there are often heavy overloads on a shaft, such as when starting up. These loads will make the shafting spring, bend and deflect. S K F Ball Bearings do not bind under these conditions as babbitt bearing do. S K F Ball Bearings pivot and yield to this springing. They turn freely in all positions. When the shaft ceases to deflect they return to their normal position, smoothly and without friction.

The third advantage gained from S K F Transmission equipment is freedom from lubrication troubles. A bearing that leaks oil soon runs dry. A dry bearing heats and wears; it scores and finally you have a hot box or a seized bearing. Then there is real trouble. S K F eliminates all this. The S K F Bearing is surrounded by an oil tight casing; the oil cannot possibly leak out. This, by preventing a dry bearing, obviates the countless troubles resulting! from a dry bearing. Also it prevents wasted lubricant. S K F Ball Bearings on transmission equipment need oil only once in four months.

S K F Transmission equipment is very compact.· The bearing and housing are only one-half to one-third as long as a plain bearing for the same shaft size.
We have special catalogs covering S K F Transmission equipment. If you are interested in saving time, money


How to Obtain SKF
In reading this book you may have found some machine that is now giving you trouble and that can be improved by the use of S K F, or perhaps you have a special machine which you want to equip with S K F. The question is how and where can you obtain S K F, and how to apply them to your machine. There are two ways. Every maker of paper and pulp mill machinery will supply S K F on new machines if you specify them. Practically every maker will replace plain bearings with S K F. Therefore by going to the maker of your machine you can have him supply you with SKF Ball Bearings and Housings. The bearings will be according to specifications furnished by us and the housings will be of our approved design.

Should your maker not be in a position to do this, write us. We will be glad to cooperate with you through our Engineering Department. Because of long experience they will be able to submit proper bearing recommendations which will be helpful to you. As the use of a high quality, serviceable bearing- · S K F- spreads, there will come a new era in paper making machinery. All will realize that the numerous troubles, due to plain bearings, now tolerated, can be eliminated by using S K F.

By co-operation between mill, machinery maker and S K F we hope to spread the use of S K F to every mill that needs and wants better machinery.

The service and advantages gained by users of S K F Ball Bearings are so tangible that the purchasing price becomes a minor consideration.