Marking Out & Measuring
The first step in the manufacturing process.
Marking out is a means of transferring shapes and lines onto material to provide a guide for cutting, bending, shaping and various other processes. Accurate marking out and measuring are important in ensuring materials will fit together properly.
The importance of marking out can be overlooked (especially by school pupils) leading to problems at the end of the manufacturing process when a product/work doesn’t fit together correctly. Another important aspect of marking out and measuring is choosing the appropriate tool to suit the material being and considering what you are trying to achieve e.g find a true edge, test for flatness or mark out a measurement.
There are a variety of marking out tool and more than one way of doing a particular task which extend beyond using just a pencil and ruler. I have seen first hand students trying to mark lines on metal and acrylic with a pencil (a blunt pencil) and drawing circles free hand. Getting to know the various options and tools available will make this important step much more successful and easier.
Marking out is a means of transferring shapes and lines onto material to provide a guide for cutting, bending, shaping and various other processes. Accurate marking out and measuring are important in ensuring materials will fit together properly.
The importance of marking out can be overlooked (especially by school pupils) leading to problems at the end of the manufacturing process when a product/work doesn’t fit together correctly. Another important aspect of marking out and measuring is choosing the appropriate tool to suit the material being and considering what you are trying to achieve e.g find a true edge, test for flatness or mark out a measurement.
There are a variety of marking out tool and more than one way of doing a particular task which extend beyond using just a pencil and ruler. I have seen first hand students trying to mark lines on metal and acrylic with a pencil (a blunt pencil) and drawing circles free hand. Getting to know the various options and tools available will make this important step much more successful and easier.
Common misconceptions with marking out in schools
One problem that can occur at the beginning stages of manufacturing is correct use of a steel rule instrument. In schools some students do not know to measure from the end of ruler (the baseline) and they instead measure from 10mm meaning that measures are all 10mm too short. It is basic information like this that a teacher may over look and feel is not needed to be explained meaning that a students accuracy in work is doomed from the off.
Other basic information that may need to considered before starting marking out is to ensure to use a sharp pencil, which again may seem simple but can have an impact on accurate measuring. Another common problem in Design and technology is some people (such as school students) do not know that millimetres are used instead of centimetres, and that 10mm equals 1cm.
One problem that can occur at the beginning stages of manufacturing is correct use of a steel rule instrument. In schools some students do not know to measure from the end of ruler (the baseline) and they instead measure from 10mm meaning that measures are all 10mm too short. It is basic information like this that a teacher may over look and feel is not needed to be explained meaning that a students accuracy in work is doomed from the off.
Other basic information that may need to considered before starting marking out is to ensure to use a sharp pencil, which again may seem simple but can have an impact on accurate measuring. Another common problem in Design and technology is some people (such as school students) do not know that millimetres are used instead of centimetres, and that 10mm equals 1cm.
Most aspects of marking out and measuring can be used across a variety of materials and the basic instruments for effective marking out include;
Marking marks
Pencil - A pencil may seem like a idiot proof instrument however they can still be used incorrectly when marking out onto material. It is important to ensure that your pencil has a sharp point as ‘fat’ lines can cause inaccuracy and ensure to stop frequently and sharpen the pencil as the tip will broaden after being pressed into the material.It is advisable to use a 2H-4H pencil as they have are harder lead and will keep there point for long, produce finer lines and will not smudge across material by hands and tools when working. A Pencil is used predominantly in woodworking particularly when not wanting to scratch the surface of the material as it can be easily rubbed out if not pressed too hard into the wood.
•Sharp scribe - Mainly used in metal working to scratch into the surface of the material and sometimes used in wood working. They are much finer and more accurate than a pencil and nearly always used with a try square and metal rule. The scratches are permanent so need to consider if they will affect the finished out come.
•Engineer's blue – A stain used in metalwork to help marking out. It is scratched off using a scribe to reveal a line in the metal underneath, an advantage of using the stain is it will cover any existing scratches/markings making new markings out clearer.
•Engineer's blue – A stain used in metalwork to help marking out. It is scratched off using a scribe to reveal a line in the metal underneath, an advantage of using the stain is it will cover any existing scratches/markings making new markings out clearer.
Felt marker- Mostly spirit based and used to mark lines on plastics and metal however can smudge easily, Not advisable to use on wood as they will permanently stain the wood. Advantages of markers is they come in a variety of tip thickness's and colours but usually fine black markers are used.
Commonalities with mark making tools
- Considered the material you are using (metal, wood, plastic) and how appropriate the tool is for the job
- Ensuring the tool is in good working order for example pencil/scribe/marker has a sharp point to create fine and accurate marking
- Consider if the marks will damage the surface of the material affecting the finished out come could you Use an overlay or tape to ensure the marks are faint or can be removed to avoid scratching/spoiling material.
Marking straight lines
•Steel rule - They not only used to measure length but also to test straightness and flatness of material, provide a straight line from one point to another. The most obvious tool for marking and measuring, can be used on any material but not always necessarily the most accurate and appropriate tool to use, it is important to consider the other options available.
•Marking gauge – used in conjunction with a steel rule to set measurement, Provides a fast and accurate way to mark out lines parallel to an edge and once set can be used multiple times, which is much more accurate than using a pencil and steel rule. Used Predominantly in woodworking particularly for joinery, however can also be used in metal working. Like a scribe it is more accurate than marking with pencil as it uses a sharp pin making a very thin mark which will not broaden.
•Try square & Engineers square - The best tool for checking a 'true' (straight) edge on material, as well flatness and marking Lines at right angles to an edge . A Try square is in woodworking and engineer is for metal due to difference in blade and stock material. However Placement of the 'Square' on the material is the same for both types of square.
Commonalities when Marking any line
•Make sure the tool is in good working order
•Ensure you are using the correct tool for the material being used.
•Ensure the tool is placed along a true edge of the material or Use a straight edge to mark along e.g Steel rule
•Use in marking tool in conjunction with another to ensure accurate measurements and position on material
•Marking gauge – used in conjunction with a steel rule to set measurement, Provides a fast and accurate way to mark out lines parallel to an edge and once set can be used multiple times, which is much more accurate than using a pencil and steel rule. Used Predominantly in woodworking particularly for joinery, however can also be used in metal working. Like a scribe it is more accurate than marking with pencil as it uses a sharp pin making a very thin mark which will not broaden.
•Try square & Engineers square - The best tool for checking a 'true' (straight) edge on material, as well flatness and marking Lines at right angles to an edge . A Try square is in woodworking and engineer is for metal due to difference in blade and stock material. However Placement of the 'Square' on the material is the same for both types of square.
Commonalities when Marking any line
•Make sure the tool is in good working order
•Ensure you are using the correct tool for the material being used.
•Ensure the tool is placed along a true edge of the material or Use a straight edge to mark along e.g Steel rule
•Use in marking tool in conjunction with another to ensure accurate measurements and position on material
Callipers
At its most basic level used as a compass to draw arc and circles, although more accurate than a normal pencil compass as it has fine scribe points. They are also used to mark lines and measure the distance between two points in conjunction with a steel rule.
- Odd leg callipers- As with a marking gauge it will scribe lines parallel to edge on a metal or plastics, the bent leg runs along the material edge and the scriber on the other leg makes a mark.once the measurement it can be used multiple times. Other uses for odd leg callipers include finding the centre of a piece of material e.g. a round bar
- Other callipers include; internal callipers for measuring inside objects and external callipers for measuring outside