« PreviousContinue »
You are expected to prove your knowledge of machinery, as well as your power of drawing neatly to scale. You are therefore to supply details omitted in the sketches, to fill in parts left incomplete, and to indicate, by diagonal lines, parts cut by planes of section.
No credit will be given unless some knowledge of projection is shown, so that at least two views of the example will be required properly projected one from the other. The centre lines should be clearly drawn. The figured dimensions need not be inserted.
Your answers should be clearly and cleanly drawn in pencil. No extra marks will be allowed for inking in.
In the Elementary and Advanced Stages the answers to the questions as well as the drawings must be made on the single numbered sheet of drawing paper supplied, for no second sheet will be allowed.
The value attached to each question is shown in brackets after the question. A full and correct answer to an easy question will secure a larger number of marks than an incomplete or inexact answer to a more difficult one.
Your name is not given to the Examiners, and you are forbidden to write to them about your answers.
You are to confine your answers strictly to the questions proposed.
A single accent (') signifies feet; a double accent (") inches. The examination in this subject lasts for four hours.
First Stage or Elementary Examination.
Read the General Instructions on page 1.
Answer briefly any three, but not more than three, of the following questions, and draw one, but not both, of the examples shown on diagram X. The example should be drawn on the side of the paper on which the candidate's number is printed.
Foolscap paper must not be used for this stage.
The sketches in answer to the questions should be drawn freehand. (a.) On a sketch drawn to a large scale show the form of section of the Whitworth screw thread. Also with the aid of another sketch describe how to set out a drawing of a screw, the V threads being represented with sharp angles, and the projections of the helical curves at the top and bottom of the threads by straight lines. (10.)
(b.) With the aid of sketches describe how to make a steamtight joint between two flanges. Explain under what circumstances studs are used instead of bolts. (10.)
(c.) Sketch and describe a construction in which by means of a right- and left-handed screw a rod may be adjusted in length; or sketch and describe any alternative method by which the length may be adjusted.
Mention one example in which such an adjustment may be necessary. (10.)
(d.) By means of sketches and a description show how you would secure a wheel or pulley to the table of a slotting machine for the purpose of cutting a key way, and how you would make the adjustment which is necessary when the key way is to be suitable for a taper key.
Show by sketches the form of the cutting tool you would use.
(e.) In example 1 diagram X show a method of preventing the nut at the end of the piston rod from working loose. Explain why a separate piece is provided and secured to the bottom surface of the cross-head, and describe how you would remove this piece for repair without disconnecting the piston rod and cross-head. (10.)
(f.) Describe the order in which the several parts of the steam valve shown in example 2, diagram X, are put together to form the whole as shown.
Draw and complete views A and B, partly in section, as on the diagram.
Draw also a third view, not in section, projected from. A, as seen when looking in the direction of the arrow above A. Scaleths.
2. Portion of a spring loaded steam vaive.
Draw views D and E, showing the former partly in section as on the diagram.
Draw also a plan projected from D. Scale full size.