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Precision Finish with
Timesaver Non-Imbedding Lapping Compound


By William F. Epmeier
Vice-President

Timesaver Products Company of Illinois
Chicago




Foreword

This treatise is prepared for the express purpose of presenting to you, by means of accurate
photo plates and comparative description, the qualities that are essential to obtain precision
fits on all bearing surfaces.

The information contained in this booklet embodies the results of 40 years experience in
research and practical application, in the field of non-charging abrasive compounds.

The Timesaver Products Company Incorporated was founded by its present owners in 1919
and up to the present time has continuously served leading manufacturers, the Army, Navy,
and Air Force, and enjoys worldwide distribution of its abrasive products.

Timesaver (Precision Finish) Lapping Compound is an improved product and represents a
recent development. The two new classes of abrasive compound, namely, grades for ferrous
metals and grades for non-ferrous metals, may be identified by their colors of green and
yellow respectively.
















Precision Finish with
Timesaver Lapping Compound

Fewer subjects related to the design and construction of machinery are of greater importance
than the problem of bearing lubrication and the reduction of friction and wear. The
importance of this subject has been especially emphasized in recent years, during which it has
been necessary for the manufacturers of mechanical devices to meet the demand for
equipment capable of greater load capacity and of higher operating speeds.

Improved design and the advanced technique of machining surfaces has made it possible to
reduce tolerances and permit closer fits between the various types of moving members of an
assembled machine.

Even with the practice of modern technique and carefully controlled production, it is,
nevertheless, impossible to hold sizes and surfaces to an exact measurement. Plus or minus
tolerances result in varying fits between moving parts. Bearing surfaces differ due to tooling
technique and the technician.

To endure higher operating speeds and greater load capacity, the contact surfaces must
possess the necessary properties to promote ideal lubrication and free movement of parts
under all operating conditions.

This can only be accomplished when the bearing surface is free from mechanical
imperfections. Too much or insufficient clearance between parts, misalignment of parts due to
improper fabrication or assembly, ridges and grooves caused by tool bits, reamers, grinding
wheels, etc., prevent the formation of a uniform film of oil, the lack of which causes metal-to-
metal contact. When metal-to-metal contact takes place, excessive friction is the immediate
result. This is followed by increased internal temperatures, irregular expansions, contractions
and distortions, scuffing, seizure and destruction of the bearing surface and the subsequent
costly replacement of parts.















Micro photographs of various metals finished by the methods indicated:



Surfaces, as the above, cannot be properly lubricated as long as the roughness
exists, hence, the run-in period. When wear finally eliminates the ridges and
grooves, the clearance between parts is usually too great.



Precision Finish with
Timesaver Lapping Compound

Surfaces are microscopically smooth, the metal structure undisturbed, open pored
and oil retaining.

To meet the demand for a simplified fitting method that is both scientific and practical, the
Timesaver Products Company pioneered in this field by developing a non-charging abrasive
compound. This compound was formulated expressly for the finishing and fitting of bearing
contact surfaces and at present is recognized as a standard medium for this purpose.
Timesaver (Precision Finish) Lapping Compound is the latest development of the Timesaver
Products Company. This new product embodies all of the features of the original compound
and in addition has the following improved characteristics:

Faster cutting action
Will produce finer finishes
Possesses the property of remaining in suspension for a longer
period of time when mixed with oil

The application procedure is so simplified that an unskilled operator will readily obtain
excellent results. From 80 to 90% bearing surfaces, with proper oil clearance, can quickly be
obtained on babbitt, bronze, brass, and cast iron bearings. Gear noises due to slight
misalignment of parts, tool marks, and other irregularities are quickly eliminated. Proper gear
tooth contact on worm, spur, herringbone and helical assemblies and microscopically smooth
surfaces are realized by the Timesaver fitting method.

Action of Timesaver Compound

The cutting action of Timesaver (Precision Finish) Lapping Compound is rapid at first and
gradually diminishes as the abrasive particles disintegrate into inoperative material. The
finishing action is such that surface irregularities and surplus metal is gently and quickly
removed without disturbing the natural metal structure.

Properties

Timesaver Lapping Compound is manufactured expressly for the purpose of fitting and
smoothing the bearing or contacting surfaces of either rotating, oscillating, or sliding parts of a
mechanism. The compound is produced in two general classes, namely grades for
ferrous metals and grades for non-ferrous metals.

Timesaver Lapping Compound does not contain emery, ground glass, silicon-
carbide, aluminum oxide, or similar permanent charging abrasives. It will not
charge into any metal surface or continue to cut.

To better describe the characteristics of Timesaver Lapping Compound, reference is made to
the following excerpt from a report on tests made by the U.S. Navy Experimental Station,
Annapolis, MD, Test No. 4387, Par. 18:

Tests made of TIMESAVER Lapping Compound bear out the claims of the manufacturers that this
compound does not imbed in the metal on which it is used, and that it quickly breaks down from an
abrasive, first to a polishing compound and then further to inert material. These qualities allow its
use where normally an abrasive could not be thought of, because particles of the ordinary abrasive
could not be fully cleaned out of the machine, and might continue to grind or scratch when or where
such action would not be desired.



Fairbanks-Morse Main Building


Timesaver Lapping Compound produced and ideal fit in one fifth of the time
formerly consumed by hand scraping.


Application

Assembly lapping of parts with Timesaver Lapping Compound, regardless of shape, size, or the
part involved, will result in:

Precision fits
Proper oil clearance
Microscopically fine finish

The ultimate result is minimized friction, freedom of motion, and long wearing parts.











Gang Saw Main Bearing


Hand scraping took six hours. It is now done with Timesaver in forty-five minutes.

Round Bearings

A bearing surface should be smooth and yet not glazed, and of exactly the same contour as
that of the member it supports. Further, a specific clearance must exist between members to
allow for the uniform maintenance of an oil film. The fitting process must be such as to
preserve the natural qualities of the bearing alloy.

Yellow label grades of Timesaver Lapping Compound are especially suited for the precision
fitting of all types of babbitt, bronze, and similar soft metal bearings. The lapping procedure is
easily and economically accomplished and will yield perfectly fitting bearings with the proper
oil clearance. Timesaver finished bearings have no high spots, consequently the necessity of a
run-in period and the related dangers of scoring and over-heating are eliminated.
Many man-hours were saved by precision lapping of this marine speed reducer unit, in
assembly, with Timesaver Lapping Compound. Assembly lapping compensates for slight
alignment irregularities, effects perfect tooth contact and quiet operation.

Gear Lapping

Regardless of accuracy or precision exercised in the cutting or assembling of gears, practiced
by modern methods, gear noises frequently occur as a result of machining irregularities or
misalignment in final assembly. These difficulties can be overcome by the use of the
Timesaver precision lapping method. This operation will definitely correct the vibration and
eliminate the noise caused by improper tooth contact. Quiet operation, superior finish, and
full tooth contact can be secured on all types of gears of various metals, which are used in
transmission assemblies, speed reducers, and elevator hoists.

The fitting can be done by either lapping the gears in a fixture or after assembly as the non-
imbedding self-eliminating nature of the Timesaver compound prevents excessive or continued
cutting.

General

Timesaver Lapping Compound is an ideal medium for the assembly lapping of all the individual
or moving parts of an assembled mechanism such as:


Gears
Bearings
Lathe and planer ways
Poppet and plug valves
Silphon type seals
Piston and cylinder walls
Relieving of hot bearings

and in fact upon any type of bearing surfaces wh