|Marking and Punch Marking - Course: Technique for manual working of materials. Trainees' handbook of lessons (Institut für Berufliche Entwicklung, 18 p.)|
Scribed lines are produced by tools which are either slightly notching the surface of the workpiece or leaving a thin line by wearing themselves,
Widely used scribing tool with hardened or carbide points which are straight or angular. It is used for rough or rough-machined steel parts and leaves a fine notch.
Figure 3 Steel scriber
Notch-sensitive materials and borders of thin sheet metal to be bent must not be scribed with steel scribers.
Risk of breakage!
Scribing tool of brass wire with filed point. It is used for scribing on finished surfaces only and applied a thin yellow line - no notching effect I
Figure 4 Brass scriber
Scribing tool for thin, notch-sensitive as well as surface-refined or very soft workpieces. It applies a black line - no notching effect!
Figure 5 Pencil
Scribing tool for scribing circular arcs and curvatures. The use of dividers always necessitates a punch mark for the guiding point. It leaves a fine notch!
Figure 6 Scribing with toolmakers dividers using an insert (1)
Customary dividers are toolmakers dividers with or without lockable legs, tool-makers dividers with adjustable points for scribing on stepped faces and beam trammels for very big curvatures.
For the use of dividers an insert may be required, if the supporting point is outside the workpiece,
Figure 7 Scribing with beam trammels using an insert (1)
Adjustable scribing tools used for scribing of parallel lines along datum faces or edges.
Customary scribing blocks are caliper gauges for quick scribing in the hand and height gauges for extensive or very accurace scribing (0.1 mm measuring accuracy) from a datum plane - the surface plate.
Scribing blocks may have graduations or not.
Figure 8 Caliper gauge scriber and height gauge scriber
Scribing of parallel lines necessitates accurately machined datum faces or edges!
Figure 9 Prick punch types
Tools of various types producing punch marks:
Marking-out punch (1)
- Angle of taper 40°, for prick-punching of scribed lines,
Centre punch (2)
- Angle of taper 60°, to produce punch marks for holes to be drilled.
Double-point punch (3)
- Punch with two points, for symmetric prick-punching of marks for bore lines.
Stencil punch (4)
- Angle of taper 60° with very slender point, for prick-punching of holes to be drilled through stencils.
Which requirements must be met by scribed lines?
Which effects must be produced by scribing tools?
What makes the difference in the use of steel scribers and brass scribers?
Which requirements must be met by workpieces for which scribing blocks shall be used?