TURNING AND
BORING

 

By FRANKLIN D. JONES

Associate Editor of MACHINERY
Author of “Planing and Milling”

 

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FIRST EDITION
FIFTH PRINTING

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NEW YORK
THE INDUSTRIAL PRESS
London: THE MACHINERY PUBLISHING CO., Ltd.
1919

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Copyright, 1914
BY
THE INDUSTRIAL PRESS
NEW YORK

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PREFACE

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Specialization in machine-tool manufacture has been developed to such a degree that there is need also for treatises which specialize on different classes of tools and their application in modern practice. This book deals exclusively with the use of various types of turning and boring machines and their attachments, and is believed to be unusually complete. In addition to standard practice, it describes many special operations seldom or never presented in text-books. Very little space is given to mere descriptions of different types of machine tools, the principal purpose being to explain the use of the machine and the practical problems connected with its operation, rather than the constructional details. No attempt has been made to describe every machine or tool which might properly be included, but rather to deal with the more important and useful operations, especially those which illustrate general principles.

Readers of mechanical literature are familiar with Machinery's 25-cent Reference Books, of which one hundred and twenty-five different titles have been published during the past six years. Many subjects, however, cannot be adequately covered in all their phases in books of this size, and in response to a demand for more comprehensive and detailed treatments on the more important mechanical subjects, it has been deemed advisable to bring out a number of larger volumes, of which this is one. This work includes much of the material published in Machinery's Reference Books Nos. 91, 92 and 95, together with a great amount of additional information on modern boring and turning methods.

It is a pleasure to acknowledge our indebtedness to the manufacturers who generously supplied illustrations and data, including many interesting operations from actual practice. Much valuable information was also obtained from Machinery.

F. D. J.

New York, May, 1914.

 

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CONTENTS

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  Pages Chapter I THE ENGINE LATHE—TURNING AND BORING OPERATIONS General Description of an Engine Lathe—Example of Cylindrical Turning—Facing the Ends Square with a Side-tool—Turning Tool—Turning Work Cylindrical—Roughing and Finishing Cuts—Filing and Finishing—Aligning Centers for Cylindrical Turning—Application of Drivers or Dogs—Lathe Arbors or Mandrels—Different Types of Lathe Arbors—Mandrel or Arbor Press—Steadyrest for Supporting Flexible Parts—Application of Steadyrest when Boring—The Follow-rest—Centering Parts to be Turned—Centering Machine—Different Forms of Centers—Precaution When Centering Tool Steel—Facing the Ends of Centered Stock—Truing Lathe Centers—Universal, Independent and Combination Chucks—Application of

Chucks—Example of Boring—Measuring Bored Holes—Setting Work in the Chuck—Inaccuracy from Pressure of Chuck Jaws—Drilling and Reaming—Holding Work on Faceplate—Application of Angle-plate to Faceplate—Supporting Outer End of Chucked Work—Boring Large Castings in the Lathe—Boring Holes to a Given Center Distance—Turning Brass, Bronze and Copper—Machining Aluminum  1-53    Chapter II LATHE TURNING TOOLS AND CUTTING SPEEDS Turning Tools for General Work—Tool-holders with Inserted Cutters—The Position of Turning Tools—Tool Grinding—Shape or Contour of Cutting Edge—Direction of Top Slope for Turning Tools—Clearance for the Cutting Edge—Angle of Tool-point and Amount of Top Slope—Grinding a Lathe Tool—Cutting Speeds and Feeds—Average Cutting Speeds for Turning—Factors which Limit the Cutting Speed—Rules for Calculating Cutting Speeds—Feed of Tool and Depth of Cut—Effect of Lubricant on Cutting Speed—Lubricants Used for Turning—Lard Oil as a Cutting Lubricant  54-79    Chapter III TAPER TURNING—SPECIAL OPERATIONS—FITTING Setting Tailstock Center for Taper Turning—Example of Taper Turning—Setting the Tailstock Center with a Caliper Tool—Setting the Tailstock Center with a Square—The Taper Attachment—Application of Taper Attachment—

tag="{http://www.w3.org/1999/xhtml}a">Height of Tool when Turning Tapers—Taper Turning with the Compound Rest—Accurate Measurement of Angles and Tapers—To Find Center Distance for a Given Taper—To Find Center Distance for a Given Angle—To Find Angle for Given Taper per Foot—To Find Angle for Given Disk Dimensions—Use of the Center Indicator—Locating Work by the Button Method—Eccentric Turning—Turning a Crankshaft in a Lathe—Special Crankshaft Lathe—Operation of Special Crankshaft Lathe—Spherical Turning—Spherical Turning Attachments—Turning with Front and Rear Tools—A Multiple-tool Lathe—Examples of Multiple Turning—Knurling in the Lathe—Relieving Attachment—Application of Relieving Attachment—Relieving Hobs or Taps Having Spiral Flutes—Classes of Fits Used in Machine Construction—Forced Fits—Allowance for Forced Fits—Pressure for Forced Fits—Allowance for Given Pressure—Shrinkage Fits  80-134    Chapter IV THREAD CUTTING IN THE LATHE Selecting the Change Gears for Thread Cutting—The Thread Tool—Cutting the Thread—Indicator or Chasing Dial for Catching Threads—Principle of the Thread Indicator—Replacing Sharpened Thread Tool—Use of Compound Rest for Thread Cutting—Threads Commonly Used—Multiple Threads—Cutting a U. S. Standard Thread—Cutting a Left-hand Thread—Cutting a Square Thread—

href="@public@vhost@g@gutenberg@html@files@34030@[email protected]#Secnum_4_13" class="pginternal" tag="{http://www.w3.org/1999/xhtml}a">Cutting Multiple Threads—Setting Tool When Cutting Multiple Threads—Taper Threading—Internal Threading—Stop for Thread Tools—The Acme Standard Thread—The Whitworth Thread—Worm Threads—Coarse Threading Attachment—Testing the Size of a Thread—The Thread Micrometer—Three-wire System of Measuring Threads—Rivett-Dock Threading Tool—Cutting Screws to Compensate for Shrinkage—Calculating Change Gears for Thread Cutting—Lathes with Compound Gearing—Fractional Threads—Change Gears for Metric Pitches—Quick Change-gear Type of Lathe  135-177    Chapter V TURRET LATHE PRACTICE General Description of a Turret Lathe—Example of Turret Lathe Work—Machining Flywheels in Turret Lathe—Finishing a Flywheel at One Setting in Turret Lathe—Finishing a Webbed Flywheel in Two Settings—Tools for Turret Lathes—Box-tools—Examples of Box-tool Turning—Hollow Mills—Releasing Die and Tap Holders—Self-opening Die Heads—Collapsing Taps—Miscellaneous Turret Lathe Tools—Turning Gasoline Engine Pistons in Turret Lathe—Turning Piston Rings in Turret Lathe—Piston Turning in Pratt and Whitney Turret Lathe—Attachment for Turning Piston Rings—Turning Worm-gear Blanks in Turret Lathe—Turning Bevel Gear Blanks—Shell Turning Operation in Flat Turret Lathe—Chuck Work in Flat Turret Lathe—

href="@public@vhost@g@gutenberg@html@files@34030@[email protected]#Secnum_5_22" class="pginternal" tag="{http://www.w3.org/1999/xhtml}a">Double-spindle Flat Turret Lathe—Automatic Chucking and Turning Machine—Example of Work on Automatic Turning Machine—Determining Speed and Feed Changes—Setting the Turret Slide—Setting the Cross-slide Cam—Setting the Boring Tool for Recessing—Adjustments for Automatic Feed and Speed Changes—Turning Flywheel in Automatic Chucking and Turning Machine—Automatic Multiple-spindle Chucking Machine—Selecting Type of Turning Machine  178-241    Chapter VI VERTICAL BORING MILL PRACTICE Boring and Turning in a Vertical Boring Mill—Holding and Setting Work on Boring Mill Table—Turning in a Boring Mill—Boring Operations—Turning Tools for the Vertical Boring Mill—Turning a Flywheel on a Vertical Mill—Convex Turning Attachment for Boring Mills—Turning Taper or Conical Surfaces—Turret-lathe Type of Vertical Boring Mill—Examples of Vertical Turret Lathe Work—Floating Reamer Holders—Multiple Cylinder Boring Machine  242-274    Chapter VII HORIZONTAL BORING MACHINES Horizontal Boring Machine with Vertical Table Adjustment—Drilling and Boring—Cutters Used—Cutter-heads for Boring Large Holes—Cylinder Boring—Boring a Duplex Gasoline Engine Cylinder—Examples of Boring, Radial Facing and Milling—Fixture for Cylinder Lining or Bushing—Horizontal Boring Machine of Floor Type  275-297    Index 299 

 

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TURNING AND BORING

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CHAPTER I

THE ENGINE LATHE—TURNING AND BORING OPERATIONS

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The standard “engine” lathe, which is the type commonly used by machinists for doing general work, is one of the most important tools in a machine shop, because it is adapted to a great variety of operations, such as turning all sorts of cylindrical and taper parts, boring holes, cutting threads, etc. The illustration Fig. 1 shows a lathe which, in many respects, represents a typical design, and while some of the parts are arranged differently on other makes, the general construction is practically the same as on the machine illustrated.

The principal parts are the bed B, the headstock H, the tailstock T, and the carriage C. The headstock contains a spindle which is rotated by a belt that passes over the cone-pulley P, and this spindle rotates the work, which is usually held between pointed or conical centers h and h1 in the headstock and tailstock, or in a chuck screwed onto the spindle instead of the faceplate F. The carriage C can be moved lengthwise along the bed by turning handle d, and it can also be moved by power, the movement being transmitted from the headstock spindle either through gears a, b, c, and lead-screw S, or by a belt operating on pulleys p and p1, which drive the feed-rod R. The lead-screw S is used when cutting threads, and the feed-rod R for ordinary turning operations; in this way the wear on the lead-screw is reduced and its accuracy is preserved.

On the carriage, there is a cross-slide D which can be moved at right angles to the lathe bed by handle e, and on D there is an upper or compound slide E which can be swiveled to different positions. The tool t, that does the turning, is clamped to the upper slide, as shown, and it can be moved with relation to the work by the movement of the carriage C along the bed, or by moving slide D crosswise. The lengthwise movement is used to feed the tool along the work when turning, boring or cutting a screw, and the crosswise movement for facing the ends of shafts, etc., or for radial turning. When the tool is to be fed at an angle, other than at right angles to the bed, slide E, which can be set to the required angle, is used. The lengthwise and crosswise feeding movements can be effected by power, the lengthwise feed being engaged by tightening knob k, and the cross-feed by tightening knob l. The direction of either of these movements can also be reversed by shifting lever r. Ordinarily the carriage and slide are adjusted by hand to bring the tool into the proper position for turning to the required diameter, and then the power feed (operating in the desired direction) is engaged. The tailstock T can be clamped in different positions along the bed, to suit the length of the work, and its center h1 can be moved in or out for a short distance, when adjusting it to the work, by turning handle n.

As some metals are much harder than others, and as the diameters of parts to be turned also vary considerably, speed changes are necessary, because if the speed is excessive, the turning tool will become dull in too short a time. These speed changes (with a belt-driven lathe) are obtained by placing the driving belt on different steps of cone-pulley P, and also by the use of back-gears. The cone-pulley can be connected directly with the spindle or be disengaged from it by means of bolt m. When the pulley and spindle are connected, five speeds (with this particular lathe) are obtained by simply shifting the driving belt to different steps of the cone. When a slower speed is required than can be obtained with the belt on the largest step of the cone, the latter is disconnected from the spindle, and the back-gears G and G1 (shown in the plan view Fig. 2) are moved forward into mesh by turning handle O; the drive is then from cone-pulley P and gear L to gear G, and from gear G1 to the large gear J on the spindle. When driving through the back-gears, five more speed changes are obtained by shifting the position of the driving belt, as before. The fastest speed with the back-gears in mesh is somewhat slower than the slowest speed when driving direct or with the back-gears out of mesh; hence, with this particular lathe, a series of ten gradually increasing speeds is obtained. Changes of feed for the turning tool are also required, and these are obtained by shifting the belt operating on pulleys p and p1 to different-sized steps. On some lathes these feed changes are obtained through gears which can be shifted to give different ratios. Many lathes also have gears in the headstock for changing the speeds.