Marking out
From Wikipedia, the free encyclopedia
Marking out or layout is the process of transferring a design or pattern to a workpiece, as the first step in the manufacturing process. It is performed in many industries or hobbies although in the repetition industries the machine's initial setup is designed to remove the need to mark out every individual piece.
The actual method is unique for each field of expertise, some common areas and their needs are listed below as examples of the variation in an otherwise simple process.
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[edit] Engineering/Machining
In the metal trades area, marking out consists of transferring the dimensions from the plan to the workpiece in preparation for the next step, machining or manufacture.
Tools that are peculiar to the engineering/machining area are typically
- Surface plate or marking out table — provides a true surface from which to work
- Angle plates — assist in holding the workpiece perpendicular to the table
- Scriber — is the equivalent of a pen or pencil. It literally scratches the metal surface leaving behind a fine, bright line.
- Vernier height gauge or scribing block — allows lines to be scribed at a preset distance, from the tables surface.
- Surface gage — an ungraduated comparison measuring tool that performs much the same function as the vernier height gage. It is often used in conjunction with a dial indicator and a precision height gage.
- Marking blue — to provide a usable writing surface by covering any existing scratches and providing a contrasting background.
- Protractor — to assist in the transfer of angular measurements
- Combination square — an alternative tool for transferring angular measurements
- Square — to transfer 90 ° angles to the workpiece
- Punches — either prick or center punch to create permanent marks or dimples for drill bits to start in.
- Ball peen hammer — used in conjunction with the punches to provide the striking blow needed.
- Dividers or measuring compass — for creating circles or arcs.
- Automatic center punch — a spring loaded punch that creates prick punch marks with out the need for a ball peen hammer
[edit] Welding
As welding does not always require the use of fine tolerances, marking out is usually performed by using centre punches, hammers, tape measures and chalk.
The "chalk" is actually a small pre-cut block of talc (soapstone). These talc blocks can be sharpened to a stronger point than the softer blackboard chalk. The color of the chalk provides good contrast against the dark color of the hot rolled steel that is generally used.
[edit] Sheetmetal
A sharp scriber along with try squares, rulers, trammels and tape measures are generally sufficient for this field
[edit] Woodworking
In carpentry and joinery practice a pencil is used for marking while in cabinetmaking a marking knife provides for greater accuracy.
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