Object

Useful model suitable for a second or third-year student; shows application of pattern and core box making, turning in wood and metal, screwing and drilling.

Material Required:-

Fig. I. A candlestick in turned brass. Shaded section shows method of construction, thick black lines being sections of castings.

Fig. I.-A candlestick in turned brass. Shaded section shows method of construction, thick black lines being sections of castings.

Boxwood for patterns. Sheet iron or zinc for templets. Fine plaster of Paris for core box. Iron rod for strengthening core box.

Method Of Procedure

I. Make templet of pillar, Fig. 1 (1), for example see Fig. 6, Ch. VII.

2. Make templet for base, Fig. 1 (5), and nozzle, Fig. 1 (3).

3. Turn pattern of pillar, Fig. 1 (1), including projections shown by dotted lines.

4. Turn core print to inside line, Fig. 1 (1), including projections shown by dotted lines.

5. See that pattern and core print are both the same length and that the projections shown by dotted lines are the same size on pattern and core print.

6. Lay pattern on some moulding sand, and pack sand all round it and level with the centre, and see that surface of sand is flat so that when the pattern is removed a sharp outline is seen.

7. Remove pattern and lay core print in, and see if there is sufficient space all round for the metal to run. If not, correct it and test again.

8. Turn the nozzle, Fig. 1 (3), to the outside line, including the dotted line.

9. Turn the base, Fig. 1 (5), inside first, then the outside and cut off.

10. Turn pan, Fig. 1 (4), and save-all, Fig. 1 (2).

11. Make core box in plaster with iron stays as shown on p. 96; where the method of making this is also described.

12. Get castings of these parts in brass or bronze as required.

13. Trim the rough lumps off the castings and immerse in weak pickle for about two hours.

14. Turn them to the correct shape, and screw the various parts so that they fit together. For method of holding turning tools see Fig. 7, Ch. VII. For turning tools suitable for this work see Figs. 22 (14-17), Ch. xvi.

15. Polish and colour down to whatever shade of colour is desired.

Fig. 2. A core box.

Fig. 2.-A core box.

16. Coat with lacquer and put together.

Decoration

This article is decorative in itself, but it could be bronzed or gilt if required. If this candlestick was made of brass, then well polished and lacquered, this is all that would be necessary.

Method Of Making Plaster Core Box

1. Have a box of moulding sand and level off the top.

2. Bury core print in to a depth of one-third or a little more, but not half.

3. Cut some pieces of flat thin metal the length, breadth, and about 3 in. deeper than you require.

4. Stick these in the sand, forming a box round the core print.

5. Take core print out of sand, well grease, and replace.

6. Mix up plaster of Paris with water to the consistency of cream and pour over core print to a depth of about 1 in. or a little more; let it set a bit, then put in iron wire stays and fill up with plaster.

7. When set, take off the sand and cut face down so that core print is embedded in the plaster exactly half-way; cut hollows for guides.

8. Do not take core print out of plaster but well grease core print, and face of plaster.

9. Place this half of core box on the sand, face uppermost; put pieces of tin round the sides as before, mix and pour plaster on this as before.

10. When set take off sand and trim off rough edges and square up to shape.

11. Wait until the whole box is thoroughly hard, then give a gentle tap and it will come apart in two halves, then remove core print.