Zusammenfassung der Ressource
Marking out
- if the parts are not the right size
- they will not fit together
- to make an accurate product, you have to prepare the materials you are going to use
- measuring and marking out where any machining operations are needed
- Datum edge
- provides a set reference point
- without a flat surface to work from, measurements will not be accurate
- could also be side, face, from where the dimensions are measured
- tolerance
- the amount that a measurement can vary from the stated value and still be acceptable
- which tool used depends on the required accuracy
- rule: 0.5 mm tolerance
- steel or plastic
- (digital) vernier calipers
- 0.02 mm
- sliding section over a steel bar, used to measure thickness or diameter of a part
- micro-meter
- 0.1 mm
- tightens onto a piece of material using a screw mechanism
- tools for marking out- lines that are to cut or processed on a piece of material
- wood
- pencil
- or a marking knife
- metal or
- plastic
- scriber
- can be used on very hard tool steel
- used like a pencil to scratch a mark in the material
- or ( for
metal)
- punch
- made form very hard tool steel, which is hit with a hammer to make a mark on the metal
- dot punch- highlights lines, marks centre of circles
- centre puch- marks centre of hole to be drilled
- drawing circles/ arcs
- for wood: compass
- for plastic/ metal: dividers
- similar to compass, but with two hard points, like a scriber, to scratch a line
- try square
- if the line is at 90 degrees top edge
- wooden stock and a carbon steel blade
- wood and plastic
- engineer's square
- same purpose, but for metals
- metal stock and blade
- angled lines
- sliding (or adjustable) bevel
- complex shapes
- use a template
- paper/ card
- check measurements again, after you have marked out
- to ensure a mistake hasn't been made before the material becomes waste