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Modern Machine-Shop Practice Novel Chapters
List of most recent chapters published for the Modern Machine-Shop Practice novel. A total of 286 chapters have been translated and the release date of the last chapter is Apr 02, 2024
Latest Release: Chapter 1 : Modern Machine-Shop Practice.by Joshua Rose.PREFACE.MODERN MACHINE-SHOP PRACTICE is pres
Modern Machine-Shop Practice.by Joshua Rose.PREFACE.MODERN MACHINE-SHOP PRACTICE is presented to American mechanics as a complete guide to the operations of the best equipped and best managed workshops, and to the care and management of engines and boiler
- 1 Modern Machine-Shop Practice.by Joshua Rose.PREFACE.MODERN MACHINE-SHOP PRACTICE is presented to American mechanics as a complete guide to the operations of the best equipped and best managed workshops, and to the care and management of engines and boiler
- 2 revolutions of the 40 wheel, the discrepancy of 1/100 being due to the 6.66 leaving a remainder and not therefore being absolutely correct.That the amount of power transmitted by gearing, whether compounded or not, is equal throughout every wheel in the t
- 3 [Ill.u.s.tration: Fig. 30.]In Fig. 30 _a_ _a_ and _b_ _b_ are the pitch circles of two wheels as before, and _c_ _c_ the pitch circle of an annular or internal gear, and D is the rolling or describing circle. When the describing point arrived at _m_, it w
- 4 [Ill.u.s.tration: Fig. 47.]But if a pair or a particular train of gears are to be constructed, then a diameter of generating circle may be selected that is considered most suitable to the particular conditions; as, for example, it may be equal to the radi
- 5 Internal or annular gear-wheels have their tooth curves formed by rolling the generating circle upon the pitch circle or base circle, upon the same general principle as external or spur-wheels. But the tooth of the annular wheel corresponds with the s.p.a
- 6 It may here be shown that a worm-wheel may be made to work correctly with a square thread. Suppose, for example, that the diameter of the generating circle be supposed to be infinite, and the sides of the thread may be accepted as rolled by the circle. On
- 7 Involute teeth possess four great advantages--1st, they are thickest at the roots, where they should be to have a maximum of strength, which is of great importance in pinions transmitting much power; 2nd, the action of the teeth will remain practically pe
- 8 [Ill.u.s.tration: Fig. 107.]A cast steel disk is turned in the lathe to the required form and outline. After turning, its circ.u.mference is serrated as shown, so as to provide protuberances, or teeth, on the face of which the cutting edges may be formed.
- 9 100 " " " " 87 to 123 "150 " " " " 123 to 200 "300 " " " " 200 to 600 "Rack " " " " 600 to rack.[6] For wheels having less than 12 teeth the Pratt and Whitney C
- 10 Rule.--Multiply the number of teeth in the smallest wheel of the train by the number of cutters it is proposed to have in the set, and divide the amount so obtained by a sum obtained as follows:-- From the number of cutters in the set subtract the number
- 11 The method of using the table is as follows:--Suppose it is required to make a set of wheels, the smallest of which is to contain 50 teeth and the largest 150, and it is determined to use but one cutter, then that cutter should be made correct for a wheel
- 12 [Ill.u.s.tration: Fig. 127.]To overcome this objection the template may be made to equal half the thickness of a tooth and its edge filed to represent a radial line on the wheel. But there are other objections, as, for example, that the template can only
- 13 From these tables may be found a tabular value which, multiplied by the pitch of the wheel to be marked (as stated at the head of the table), will give the setting number on the graduated edge of the instrument, the procedure being as follows:-- For the t
- 14 Each of these parts is marked with the number of teeth the wheel is to contain, and with the pitch of the teeth as shown in Fig. 140, which represents part C full size. Now suppose it is required to find the thickness at the root, for a tooth of a wheel h
- 15 [Ill.u.s.tration: Fig. 154.]The error in the set of the compa.s.ses as shown by the distance apart of the two marks E and I on the circle in Fig. 152 is too fine to render it practicable to remedy it by moving the compa.s.s legs, hence we effect the adjus
- 16 [Ill.u.s.tration: Fig. 172.]It now remains to draw in the top of the thread upon the curved surface of the half pattern; for this purpose take a piece of stiff card or other flexible material, wrap it around the pattern and fix it temporarily by tacks, we
- 17 The following table gives the safe working pressures for wheels having an inch pitch and an inch face when working at the given velocities, S.W.P. standing for "safe working pressure:"-- +------------+------------+------------+------------+-----
- 18 Second, 72/47.1 = 1.53 inch equal to the pitch.This is nearly 1-1/2-inch pitch, and if possible the diameter would be reduced or the number of teeth increased so as to make the wheel exactly 1-1/2-inch pitch.Rule 3.--Given ---- pitch and pitch diameter; t
- 19 "But these circular arcs may be rectified and subdivided with great facility and accuracy by a very simple process, which we take from Prof.Rankine's "Machinery and Mill Work," and is ill.u.s.trated in Fig. 195. Let O B be tangent at O
- 20 To obtain the forms of the teeth, therefore, take any convenient describing circle, and employ it to describe the teeth of the pinion by rolling within its pitch circle, and to describe the teeth of the wheel by rolling within and without its pitch circle
- 21 [Ill.u.s.tration: Fig. 229.][Ill.u.s.tration: Fig. 230.][Ill.u.s.tration: Fig. 231.][Ill.u.s.tration: Fig. 232.]To compare the motions of the respective rollers along the line of motion A A we proceed as in Fig. 232, in which the two dots M and N are the
- 22 CHAPTER IV.--SCREW THREAD.Screw threads are employed for two princ.i.p.al purposes--for holding or securing, and for transmitting motion. There are in use, in ordinary machine shop practice, four forms of screw thread. There is, first, the sharp [V]-threa
- 23 [Ill.u.s.tration: Fig. 267.]So far, however, we have only considered the wear tending to round off the sharp corners of the teeth, which wear is greater in proportion as the corners are sharp, and less as they are rounded or flattened, and we have to cons
- 24 So far as the diameter of a thread is concerned it may be measured by calipers applied between the threads as in Figs. 280 and 281, a plan that is commonly practised in the workshop when there is at hand a standard thread or gauge known to be of proper di
- 25 For cutting external or male threads by hand three cla.s.ses of tools are employed.The first is the screw plate shown in Fig. 292. It consists of a hardened steel plate containing holes of varying diameters and threaded with screw threads of different pit
- 26 The teeth for adjustable dies, such as shown in Fig. 293, are cut as follows:--There is inserted between the two dies a piece of metal, separating them when set together to a distance equal to twice the depth of the thread, added to the distance the faces
- 27 Another form of free cutting tap especially applicable to taps of large diameter has been designed by Professor Sweet. Its principles may be explained as follows:-- In the ordinary tap, with the taper four or five diameters in length, there are far more c
- 28 A defect in taps which it has been found so far impracticable to eliminate is the alteration of pitch which takes place during the hardening process. The direction as well as the amount of this variation is variable even with the most uniform grades of st
- 29 To insure that a tap shall tap a hole straight, the machinist, in the case of hand tapping, applies a square to the work and the tap, as shown in Fig. 361, in which W represents a piece of work, T a tap, and S S two squares. If the tap is a taper one the
- 30 TABLE OF THE FRANKLIN INSt.i.tUTE STANDARD DIMENSIONS FOR THE HEADS OF BOLTS AND FOR THEIR NUTS, WHEN BOTH HEADS AND NUTS ARE OF HEXAGON FORM, AND ARE POLISHED OR FINISHED.+------------+-------------+-----------+---------------+-----------+ | Diameter | D
- 31 [Ill.u.s.tration: Fig. 404.]A plain tap bolt should be turned up along its body, because if out of true the hole it pa.s.ses through must be made large enough to suit the eccentricity of the bolt, or else a portion of the wrench pressure will be expended
- 32 [Ill.u.s.tration: Fig. 433.]In cases where nuts are placed under rapid vibration or motion they are sometimes detained in their places by pins or cotters. The simplest form of pin used for this purpose is the split pin, shown in Fig. 431. It is made from
- 33 The proper angle of the jaws to the centre line of the jaws may be determined as follows:--The most desirable angle is that which will enable the wrench to operate the nut with the least amount of wrench-motion, an object that is of great importance in ca
- 34 If two set screws are placed diametrally opposite they will drive by the contact of their ends only, and not by reason of their inducing frictional contact between the bore and the shaft.A very true method of securing a hub to a shaft is to bore it larger
- 35 [Ill.u.s.tration: Fig. 480.]The sizes of lathes are designated in three ways, as follows:--First by the _swing_ of the lathe and the total length of the bed, the term _swing_ meaning the largest diameter of work that the lathe is capable of revolving or s
- 36 [Ill.u.s.tration: Fig. 495.]The thread on S at Z, Fig. 494, is to receive and drive the face plates, chucks, &c., which are bored and threaded to fit over Z. To cause the radial faces of such face plates or chucks to run true, there is provided the plain
- 37 Fig. 503 represents the change wheel swing frame, an edge view of which is partly shown at W in Fig. 494. S is a slot narrower at _a_ than at _b_. Into this slot fit the studs for carrying the change wheels.By enabling a feed traverse in either direction
- 38 [Ill.u.s.tration: Fig. 515.]All these parts are enclosed in a tight cast-iron tail-block, which serves as an oil well to insure constant and perfect lubrication. The surfaces which confine the revolving collar back and front are so adjusted as to allow pe
- 39 [Ill.u.s.tration: Fig. 530.]Wood turners sometimes have their lathes so made that the headstock can be turned end for end on the lathe shears, so that the face plate may project beyond the bed, enabling it to turn work of large diameter. A better method t
- 40 [Ill.u.s.tration: Fig. 545.]The face plate is 12 feet diameter, cast with internal gear at the back.It is provided with [T]-slots and square holes for fixing work. It is bolted to a large f.l.a.n.g.e in one piece with the spindle, and fitted with four ste
- 41 In some cases, as in spinning lathes, the order of the steps is reversed, the smallest step of the cone being nearest to the live centre, the object being to have the largest step on the left, and therefore more out of the way.The steps of the cone should
- 42 +-------------+-----------+-----------------------------+ | Average | Adjacent | DISTANCE BETWEEN THE CENTRES| | difference | steps, | OF CONE PULLEYS. | | between | whose +----+----+----+----+----+----+ | the | diffe- | | | | | | | | adjacent | rence is
- 43 The actual diameters, when thickness of belt = 0.20 in., are: 5.8 11.8 17.8 23.8 on cone A.29.8 25.36 20.08 13.7 " B.And the length of belt will be: [3.5080 - (3.5080 - 3.4137) 0.04] 40 in. = 140.17 in.EXAMPLE 3. Given the effective diameters: 12 in.
- 44 With the lever L in the position shown, neither B nor E engages with A, hence they are at rest; but if lever L be raised as in Fig. 567, B will gear with wheels A and C, and motion will be conveyed from A to C, wheel E running as an idle wheel, thus C wil
- 45 A similar locking device is provided for the pinion B for actuating A; thus in Fig. 582 B is the lever, the spring pin being at R"; or referring to Fig. 584, X is the lever fast at _x_ on the pin driving B, and R" is the spring pin.The nut for t
- 46 Fig. 594.Fig. 595.Fig. 596.Fig. 597.Fig. 598.Fig. 599.Fig. 600.Fig. 601.Fig. 602.Fig. 603.Fig. 604.Fig. 605.Fig. 606.]Fig. 608 shows the tool in position, held by a single screw, for work requiring the tool to be close up to the work driver. In Fig. 609 a
- 47 A lead screw should preferably be as near as possible to the middle of the lathe shears, and as close to the surface as possible, so as to bring it as nearly in line with the strain on the tool as possible, but on account of the cuttings, which falling up
- 48 By continuing the table for other pitches we shall find that in the first vertical column the denominators diminish by 4, the second column by 5, and the third by 6; and it is seen that by diminis.h.i.+ng the pitch of the lead screw, we have rendered nece
- 49 The tailblock of a lathe should be capable of easy motion for adjustment along the shears, or bed of the lathe, and readily fixable in its adjusted position. The design should be such as to hold the axial line of its spindle true with the axial line of th
- 50 The lathe is made in many special or limited forms, to suit particular purposes, the object being to increase its efficiency for those purposes, which necessarily diminishes its capacity for general work.In addition to this, however, there are machine too
- 51 The construction of this sliding-spindle head is shown in Fig. 666, in which a wire chuck is shown in position in the spindles; L is the live spindle pa.s.sing through parallel bearings, so that it may have end motion when the nut M is operated. The inner
- 52 The manner in which these results are accomplished is as follows: The headstock B and the tailstock are attached to the bed or table A, which is pivoted at its centre to a table beneath it, this latter table being denoted by C. This permits table A to swi
- 53 When, however, K is operated from left to right L moves back, and when it has traversed a certain distance, the head F rotates 1/7 of a rotation, and becomes again locked so far as rotation is concerned. Now the relation between the seven holes in F is su
- 54 [Ill.u.s.tration: Fig. 705.]Fig. 705 is a sectional and end view of the core A of the chuck, and Fig. 706 a sectional and end view of the sh.e.l.l D.[Ill.u.s.tration: Fig. 706.]Fig. 707 represents a sectional side view and an end view of the cross slide,
- 55 When the tools, cutters, and belts are all properly adjusted in position to cut to the required respective diameters or lengths the operator has simply to place a stick of wood in the lathe and operate the respective handles or levers in their proper cons
- 56 [Ill.u.s.tration: Fig. 734.]3rd. The rest for traversing single pointed screw cutting tools or chasers (for internal threads) is at the back of the lathe where it is out of the way.4th. In place of the usual change wheels required to operate the lead scre
- 57 [Ill.u.s.tration: Fig. 746.]Fig. 745 represents a lathe dog, driver, or carrier D, in position to drive a piece of work in the lathe. It is obvious that the work is secured within the carrier or driver by means of the set-screw shown.The tail of the drive
- 58 [Ill.u.s.tration: Fig. 771.][Ill.u.s.tration: Fig. 772.]When a piece of work to be turned between the lathe centres is of such a form that there is no place to receive centres, provision must be made to supply the deficiency.[Ill.u.s.tration: Fig. 773.]In
- 59 [Ill.u.s.tration: Fig. 795.]When a mandrel is fitted to the sockets for the lathe centre, it should have a thread and nut, as shown in Fig. 795, so as to enable its extraction from the socket without striking it, as has been described with reference to la
- 60 The set-screws are so adjusted upon the work, that the outside runs quite true from end to end. The jaws of the steady rest are then set to just touch the circ.u.mference of the sleeve, care being taken that their pressure does not spring the axial line o
- 61 Fig. 829 also represents a two-jawed chuck, the body being cylindrical, and having a [V]-groove at A to receive the work. The screws C, D may act independently of each other, or a continuous screw may be used, having, as in the figure, a left-hand thread
- 62 [Ill.u.s.tration: Fig. 852.]The Judson patent chuck is designed to overcome this difficulty, and is constructed as shown in Figs. 851 and 852, the former being a face view and the latter a sectional edge view of the chuck.The jaws A of the chuck are hollo
- 63 [Ill.u.s.tration: Fig. 870.]This could be held as shown in Fig. 869, in which C is the chuck plate, W the work, S a strap plate, and B, B are bolts and nuts, a face view of the work already chucked being shown in Fig. 870. The surface of the work being bo
- 64 [Ill.u.s.tration: Fig. 889.]It is obvious that the pin may be pa.s.sed through one of the radial slots in the chuck, and set the required distance from the centre, but in this case the pin would be liable to become moved in its position in the slot.Side p
- 65 [Ill.u.s.tration: Fig. 912.]The inside faces of the cheeks are turned to the dotted lines shown in Fig. 909, and the outside faces being turned each to the proper thickness measured from the outside ones, the job will be complete and true in every directi
- 66 In Fig. 921 let W represent the work having a cut C being taken off by the tool T; let E represent the slide rest, and F the extreme point at which the tool is supported; then the pressure placed by C on the top face of the tool will be at a right angle t
- 67 Both these guides, however, can only be applied to metal not unusually hard, and to tools rigidly held, and having their cutting edges sufficiently close to the tool point or clamp that the tool itself will not bend and spring from the pressure of the cut
- 68 When the tool is very narrow at _c_, Fig. 960, or long as in Fig. 961, it may be strengthened by being deepened, the bottom B projecting below the level of the tool steel, which will prevent undue spring and the chattering to which this tool is liable.[Il
- 69 But in the case of a tool holder, or of a chaser holder, the tool may be ground on the top face, and adjusted for height by any suitable means, the top of the holder serving as a guide to set the tool by.[Ill.u.s.tration: Fig. 986.]The line of the cutting
- 70 [Ill.u.s.tration: Fig. 1011.]Since, however, it is impracticable to measure male threads at the root, it becomes a problem as to the proper size of hole to bore for any given diameter and pitch of thread. This, however, may be done by the following rules:
- 71 If, for example, a piece of work requires the use of two or more such tools, and the holder is once set, the tools may be removed and interchanged with a certainty that each one put into place will stand at the exact angle and position required, not only
- 72 " 5 " " 2-1/32 " 2-1/2 " "These sockets are manufactured ready to receive the drills, but are left unturned at the shank end so that they may be fitted to the particular lathe or machine in which they are to be used, no stand
- 73 Referring to a 1/2 inch twist drill, it is said: "The time occupied from the starting of each hole in a hammered sc.r.a.p-iron bar till the drill pierced through it varied from 1 minute 20 seconds to 1-1/2 minutes. The holes drilled were perfectly st
- 74 1083. The reamer is fed end-ways into the work at a cutting speed of about 15 to 18 feet per minute.[Ill.u.s.tration: Fig. 1081.][Ill.u.s.tration: Fig. 1082.]The main considerations in determining the form of a reamer are as follows:-- 1. The number of it
- 75 Three or more washers may thus be used for every standard size, their thickness varying to suit the nature of the fit required.[Ill.u.s.tration: Fig. 1103.]It will be noted that it is mentioned that three _or more_ washers may be used, and this occurs bec
- 76 A boring tool holder suitable for holes of from 2 to 4 or 5 inches is shown in Fig. 1118, in which A represents a round bar shaped at the end B to fit into the tool post of the slide rest, and having a groove across the diameter of the end C D to receive
- 77 The considerations, therefore, which determine the shape of a cutter to be employed are as follows: Cutters for use on a certain and unvarying size of bore should have no clearance on the diametrical edges, the cutting being performed by the end edge only
- 78 Lathe Number 2.--Turning tool steel 2 inches long and 1/2 inch diameter, reducing diameter 1/8 inch. Revolutions of work 100 per minute. Feed 200 lathe revolutions per inch of tool travel.Lathe Number 3.--Turning tool steel 4 inches long and 7/8 inch in d
- 79 If the live centre does not run true the following difficulties are met with.[Ill.u.s.tration: Fig. 1156.]If one end only of the work requires to be turned and it can be completely finished without moving the work driver, the work will be true (a.s.suming
- 80 [Ill.u.s.tration: Fig. 1173.]In Fig. 1174 is shown a device for guiding the centre punch true with the axis of the work, so as to avoid the necessity of finding the same by lines for the centres. It consists of a guide piece B and a parallel cylindrical c
- 81 To prevent the weight of the work from causing the countersinking being out of true with the hole, the work should be occasionally allowed (by relaxing the grip upon it) to make part of a revolution, as explained with reference to centre-drilling without
- 82 [Ill.u.s.tration: Fig. 1209.]When the pressure between the tool and the work is sufficient, from the proportions of the work, to cause the work to spring or bend, the length of acting cutting edge on the tool should be reduced.As the diameter and rigidity
- 83 [Ill.u.s.tration: Fig. 1210.]If it be attempted with steel tools to take a very fine cut, as, say, one of sufficient depth to reduce a diameter, say 1/500 inch, the tool is apt to turn an uneven surface. There appears, indeed, to be a necessity to have th
- 84 [Ill.u.s.tration: Fig. 1218.]Figs. 1218 and 1219 ill.u.s.trate this method of setting. A represents a piece of work requiring to be turned taper from B to C, and turned down to within 1/32 inch of the required size at E and F. If then we place the tool po
- 85 In the case of a ring too thin to permit this, and of too large a bore to warrant making a mandrel for it, the ring may be held on the outside and bored, and both radial faces turned to within a short distance of the chuck jaws; at the second chucking, th
- 86 [Ill.u.s.tration: Fig. 1237.]The term "compounded" as applied to the change gears of a lathe, means that there exists in it a shaft or some equivalent means by which the velocity of the wheels may be changed. Such a shaft is shown at R in Fig. 1
- 87 It is obviously necessary, in cutting multiple threads in this way, to so select the change wheels that the driving gear contains a number of teeth that is divisible without leaving a remainder by the thread to be cut: thus, for a double thread the teeth
- 88 [Ill.u.s.tration: Fig. 1266.][Ill.u.s.tration: Fig. 1267.]The half bearing B, Fig. 1266, is chucked upon a half-round mandrel, C being the spherical surface to be turned, a sectional view of C being shown in Fig. 1267.[Ill.u.s.tration: Fig. 1268.]In Fig.
- 89 1286, the heel being pressed down firmly upon the tool rest. The cut is carried along the work by revolving the handle upon its axis, and from the right towards the left, at the same time that the handle is moved bodily from the left towards the right. By
- 90 [Ill.u.s.tration: Fig. 1310.]It is obvious that the sc.r.a.per may be given any required shape to meet the work, Fig. 1310 representing a sc.r.a.per of this kind; but it must in this case be fed endways only to its cut, if the work is to be cut to fit the
- 91 The reason for running the lathe at a comparatively fast speed is that the tool is then less likely to be checked in its movement by a seam or hard place in the metal of the bolt, and that, even if the metal is soft and uniform in its texture, it is easie
- 92 At the time the Government established the use of the standard system of screw threads in the navy yards, ten sets of gauges were ordered from a manufacturer. His firm procured a duplicate set of these and took them to the navy yard in Boston and found th
- 93 If the degree of contact is regulated by devices connected with the moving mechanism of the machine it is indirect, and may vary from causes acting upon that mechanism. But if it is regulated between the work and the moving piece that measures it, nothing
- 94 [Ill.u.s.tration: Fig. 1375.]Fig. 1375 shows a similar reading, in which the points do not coincide with the cross threads of the microscope.[Ill.u.s.tration: Fig. 1376.]Fig. 1376 shows the microscope adjusted for testing by turning the circle a quarter r
- 95 [Ill.u.s.tration: Fig. 1392.][Ill.u.s.tration: Fig. 1393.][Ill.u.s.tration: _VOL. I._ =DIVIDING ENGINE AND MICROMETER.= _PLATE XV._ Fig. 1385.Fig. 1386.Fig. 1387.Fig. 1388.Fig. 1389.Fig. 1390.Fig. 1391.]Fig. 1392 represents a vernier caliper, in which the
- 96 What system can we adopt that will enable workmen of limited capacity to do work that will be practically accurate? The taper bolt for certain purposes presents a very decided advantage. Bolts may be made practically of the same diameter, but holes cannot
- 97 Fig. 1417, for example, represents the ordinary form, the points being rounded; hence, when the legs are closed the point of contact between the inside and outside calipers will be at A, while when they are opened out to their fullest the points of contac
- 98 Let the length of the wheel bore be 7 inches long, and the amount allowed for forcing be .004 inch, and one end of the wheel bore will have been forced (by the time it is home on the axle) over the length of 7 inches of the axle-seat, whose diameter was .
- 99 The bands for this purpose are usually of wrought iron, and require in the case of irregular surfaces to be driven on by hammer blows, so that the fit may be correct. As the band is forced on a heavy hammer is held against it, to prevent its moving back a
- 100 Fig. 1430.]The plate was subjected to fifty heatings to redness and subsequent coolings in water of ordinary temperature. At every tenth cooling accurate measurements were taken of the contraction in superficial dimensions, and Fig. 1430 shows the final f