Hammering and Marking - Course: Technique for Manual Working of Materials. Instruction Examples for Practical Vocational Training: Instruction example 3.6. Table to determine Tapping Drill Holes and Bore Depths

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

Instruction example 3.6. Table to determine Tapping Drill Holes and Bore Depths

Material

General-purpose constructional steel sheet (350 MPa)
Thickness: 2 mm
Width: 50 mm
Length: 80 mm

Figure

Hand tools

Hand hacksaw or lever shear, scriber, centre punch, smooth-cut file 200 mm (flat), marking punch (figures and letters), 4.0 mm dia. drill, engineers’ hammer (500 g)

Measuring and testing tools

Steel measuring tool, radius gauge 40 mm

Accessories

Surface plate

Required previous knowledge

Reading of drawings, measuring and testing, marking and punch-marking.

Sequence of operations	Comments
1. Arrange the working place, prepare the working materials.	- Check for completeness.
2. Check for initial dimensions, otherwise cut sheet to size (outside dimensions), scribe and file to size with flat file (including radii).
3. Scribe the grid lines for guidance of the figure and letter punches.	The auxiliary lines must be in accordance with the height of figures and letters.
4. Punch-mark as specified.
5. Fine-finish the surface. Hammer all outside edges by gentle oblique blows (with the hammer pane).
6. Final inspection.	Dimensions, uniformity of table figures.

Table