Hammering and Marking - Course: Technique for Manual Working of Materials. Instruction Examples for Practical Vocational Training: Instruction example 3.5. Bowl with Cover

Hammering and Marking - Course: Technique for Manual Working of Materials. Instruction Examples for Practical Vocational Training

		(introduction...)
		Introduction
		Instruction example 3.1. Nameplate
		Instruction example 3.2. Number Plate for Locker
		Instruction example 3.3. Screw Driver
		Instruction example 3.4. Copper Bit of a Soldering Iron
		Instruction example 3.5. Bowl with Cover
		Instruction example 3.6. Table to determine Tapping Drill Holes and Bore Depths
		Instruction example 3.7. Table to determine Widths across Flats and Widths across Corners of Hexagonal-Head Screws

To practise chasing and flanging of sheet copper.

Material

2 pcs. of copper sheets
Thickness: 0.8 - 1 mm
Diameter: 50 mm and 55 mm.

Figure

Hand tools

Dividers, chasing hammer, engineers’ hammer (500 g), lever shear, wooden hammer (radiused).

Measuring and testing tools

Steel measuring tool.

Accessories

Anvil or surface plate, bordering tool, short piece of steel tube for cover of 80 mm diameter. C clamp, small sand-bag, fire, water.

Required previous knowledge

Reading of drawings, measuring and testing, scribing.

Sequence of operations	Comments
1. Arrange working place, prepare working tools.	- Check for completeness.
2. Check the diameters, otherwise cut copper sheets to size (initial size) by means of lever shear.	- Scribe with dividers.
3. Hammer steadily with chasing hammer spirally from the centre outward.	- Turn sheet with the anvil! (1) hammer-blow marks
4. Fire-anneal in steps (check for clear, short sound), quench in cold water, then continue hammering until bowl form is reached (size 80).
5. Produce final form of bowl (if necessary only) by hammering in the sand-bag constantly rotating the bowl.	- Apply gentle hammer blows only! Use wooden hammer (radiused)!
6. Hammer flat face for standing of bowl in opposite direction (size 20)	- Use hammer pane of engineers’ hammer.
7. Check second copper sheet for diameter 85, put on steel - tube piece and clamp with C clamp.	- Put centrally on tube piece, scribe checking line dia. 80, if necessary.
8. Bend down (flange) projecting border by means of engineers’ hammer and bordering tool or wooden hammer.
9. Bulge-in and smooth puckers with engineers’ hammer.
10. Final inspection.	- Uniformity of roundness, fitting accuracy of cover.

Bowl with Cover