Task: Using the two SOP templates. Create a Standard Operating Procedure for 'facing' on the lathe and another SOP for a tool of your choice. You are to include these in your folio.
How to use the metal Lathe
To begin turning metal, the workpiece must be placed firmly in the lathe. Also called 'chucking'
Chucking the Workpiece A workpiece that is relatively short compared to its diameter is stiff enough that it can be safely turned in a ‘chuck’ without supporting the free end of the work. Longer workpieces need to be ‘faced’ and ‘centred’ at the free end and use a ‘dead center’ at the tailstock to support it. Without this support, the force of the tool on the workpiece would cause it to bend away from the tool, producing a strangely shaped result. There is also the potential that the work could be forced to loosen in the chuck jaws and fly out as a dangerous projectile. Insert the workpiece in the ‘chuck’ and tighten down the jaws until they just start to grip the workpiece. Turn the chuck by hand to make sure it will in fact turn and that the workpiece is seated evenly and will ‘run true’. Then tighten the chuck using each of the chuck key positions to ensure a tight and even grip. Adjusting the Tool For most turning operations the tool height should be the same height as the centre of the workpiece. Make sure that there is adequate travel backwards and forward on both the 'cross slide' and the 'compound slide'. Speed To determine the cutting speed, the formula to the right must be used. The Cutting speed (CS), usually in units 'fpm' or feet per minute is dependant on the type of metal being cut. this figure is usually found in a table or engineers booklet. Obviously the exact speed required can not always be achieved exactly, however the closest speed the lathe can be set to will suffice. Turning by 'Hand Feeding' A great rule to think of while metal turning is: "slow is smooth, smooth is fast!" operate the lathe slowly, take your time, thoroughly think about what you are doing with each pass. remember to take little amounts off with each pass and an even speed of feeding will ensure the workpiece will be turned into a smooth and accurate pice of fabricated metal. |
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