Modern Machine-Shop Practice Part 266

The star-shaped frame is termed a sinker, and if upon being lifted from the lead the colour of the spring is too high, a second immersion is given.

APPENDICES

APPENDIX--PART I.

TEST QUESTIONS FOR ENGINEERS.

An efficient engineer must certainly be able to determine any practical question that may arise in the management, not only of his engine and boiler, but also in that of such shafting, pulleys, gear wheels, etc., as may const.i.tute the driving gear connected with the engine.

A very moderate examination of an engineer (whether to test his suitability for employment or for promotion) should therefore include questions tending to determine his capability to give such directions as may be necessary when the engine or shafting breaks down, or when alterations are to be made and he is consulted with reference to them.

The following questions have been framed with a view to include such information as a first-cla.s.s engineer, and even an a.s.sistant or night engineer, may be expected to possess, and a large proportion of these questions have been taken from actual engineers' examinations in various parts of the country.

In many cases engineers of manufactories are required to make, as far as possible, their own repairs and sometimes indeed also the repairs to the machinery the engine drives, but to give questions covering this ground would be to refer the reader to nearly every page in the two volumes, which is manifestly impracticable.

=Matching gear wheels.=--Suppose you were running a hoisting engine whose pinion had 15 teeth, driving a wheel with 150 teeth in it; if the pinion had teeth with radial flanks, what orders would you send to get another wheel that would work with the pair?--For answer, see Volume I., page 15.

=Radial flanks.=--If a pinion has radial flanks what information does that give to the engineer if at any time he requires to order another wheel to work with it? I. 15.

=Teeth of gear wheels.=--What is the difference between an epicycloidal tooth and an involute tooth of a gear wheel? I. 8, 13.

=Ordering bevel gears.=--Two lines of shafting are to be connected by a pair of bevel gears and one is to run twice as fast as the other; how would you find the bevel of the wheels so as to be able to tell the maker what was wanted, and what dimensions would you give, leaving the pitch and the shape of the teeth out of the question? I. 22.

=Ordering taps.=--Suppose you were ordering a set of taps for use in the engine room, what precautions would you be obliged to take as to the shape of the thread in order to get proper taps? I. 85.

=Fitting a nut.=--Will a nut having a United States standard thread fit a bolt having a common V thread, both threads having the same pitch and diameter, and how could you tell one bolt from the other? I. 85.

=Curing a pounding cam.=--Suppose some part of the machinery driven by an engine had a cam motion with a small roller which hammered and pounded on the cam, how would you cure the defect? I. 83.

=Ordering a new spur wheel.=--Suppose a spur wheel broke and you wanted to give the diameter for a new one, where would you measure the diameter of the old one? I. 1.

=Comparing screw threads.=--What is the difference between the common V thread and the United States standard thread? I. 85.

=Using two set screws.=--When two set screws are placed in a hub how should they be located? I. 127.

=Best lathe tool.=--What is the most useful turning tool for a hand lathe, such as is sometimes provided for an engineer to make repairs with? I. 331.

=Fitting a crank pin.=--How would you proceed to put in by a contraction fit a crank pin, the crank being on the engine? I. 366.

=Increasing strength of teeth.=--Suppose you had to order a new pair of wheels to replace a pair whose teeth frequently broke, what alterations in the dimensions of the wheels would you make so as to get stronger teeth in wheels of the same diameter? I. 65.

=Wear of a cam roller.=--If an engine had a valve motion worked by a parallel roller in a parallel cam groove, would the roller wear out quick, and why? I. 84.

=Altering the speed of a shaft.=--Do a pair of mitre wheels alter the speeds of the shaft they drive or not? I. 1.

=Driving out a key.=--In driving out a key is a quick or a slow hammer blow the most effective? II. 65.

=Riveting a crank pin.=--For riveting a crank pin what shape should the pene or pane of the hammer be? II. 73.

=Face of a cold chisel.=--What is the proper shape for the face of a cold chisel? II. 73.

=Key bearing.=--What is the effect upon a wheel if its key bears upon opposite corners? II. 107.

=Fitting a key.=--Should a key be driven lightly or not when fitting it, and why? II. 106.

=Angle Of wrench jaws.=--What angle should the jaws of a wrench be to its body in order to enable it to turn a nut in a corner with greatest advantage? I. 123.

=Chucking a crank.=--How should a crank be chucked in order to prevent the crank pin from being out of true, and the engine from beating and pounding? I. 247.

=Chucking a cross-head.=--How should a cross-head be chucked so as to have its piston rod and wrist pin at a true right angle? I. 252.

=Length of drill edges.=--Why should both edges of a drill be exactly equal in length and of equal angle? I. 277.

=Boring bar edges.=--Should a boring bar for an engine cylinder have one, two, three or four cutters? I. 289.

=Spiral spring.=--Give a method of making a spiral spring. I. 329.

=Expansion fit.=--What is meant by an expansion or a contraction fit, say for an engine crank pin? I. 366.

=Fitting bra.s.ses.=--Suppose the joint faces of a pair of bra.s.ses are not square with the sides of the box or strap in which the bra.s.ses fit, what will the effect be when the bra.s.ses are locked tight together by the key? II. 125.

=Wear of bra.s.ses.=--When an engineer is taking up the wear of connecting rod bra.s.ses, what must he do to keep the rod of the proper length? II.

124-127.

=Case hardening.=--Describe the simplest method of case hardening. II.

128.

=Fitting pillar block bra.s.ses.=--State the proper order of procedure in fitting in a new pair of main bearing or pillar block bra.s.ses for an engine. II. 130.

=Driving bra.s.ses.=--What will be the effect of driving a bra.s.s in and out with a hammer and without a block of wood to strike on? II. 72 and 132.

=Originating a true plane.=--How is a true plane or flat surface originated? II. 133.

=Cover joint.=--What is the best form of joint for an engine cylinder cover? II. 137.

=Grinding a cover.=--How must a cylinder cover be moved when grinding it? II. 137.

=Appearance Of a joint.=--What is the appearance of a finished ground joint? II. 137.

=Grade of emery.=--About what grade of emery would you use to make a ground joint? II. 137.

=Best heat joint.=--What is the best kind of joint to withstand great heat or flame? II. 138.