A metal lathe is a useful tool for shaping and shearing metal, but it is has limitations on the size of object, or stock, it can handle. To determine the maximum size of an object that your lathe can accommodate, you must measure its "swing." You can readily determine this measurement by following a few simple steps.
Verify that your lathe is deactivated. Unplug your lathe and let it sit for five minutes, to make sure that all of the power has dissipated.
Locate your lathe's chuck. The chuck is the cylindrical metal piece that holds your cutting tool while you operate the lathe.
Measure the distance between the center of your lathe’s chuck down to the top of the lathe bed. The lathe bed is the horizontal surface that runs between your lathe’s headstock and its tailstock. Record the measurement in inches
Double the measurement. The doubled measurement is your lathe’s swing.