This section is from the book "Lathe Design, Construction And Operation, With Practical Examples Of The Lathe Work", by Oscar E. Perrigo. Also available from Amazon: Lathe Design: Construction And Operation.
To secure proper results from a lathe or other machine tool it is necessary to keep all working parts properly lubricated as the neglect of this essential precaution means rapid depreciation of the various members upon which the maintenance of accuracy depends. Lubricating oil should be of the best quality and free from acid. After lathe is properly located, the various revolving parts of the lathe and the countershaft bearings are well lubricated. The various oil holes are usually clearly indicated by small, plugs having a knob on the end by which they may be removed easily. After flushing the bearings liberally with oil, the plugs are reinserted in the oil holes to keep dust and dirt out. The main spindle bearings are usually provided with oilers of this type. The spindle drive cone bearings are oiled by removing small headless set screws located on both large and small steps of the pulley group. The back gear quill bearings are oiled through small oil holes on that member. Use plenty of oil on the lead screw and half nuts before cutting a thread to prevent cutting the babbit metal in the half nuts. Oil the head spindle bearings at least every day and if the lathe is on hard work, it will be well to supply oil copiously several times every day. The mechanism of the apron. the lead screw bearings, the change speed or feed gears and all other parts should be well oiled at all times.
After the lathe is well oiled, run it for a few minutes after it is first installed to make sure that there is no binding in the bearings, or that they are not adjusted too tightly. Heating indicates friction due to lack of oiling, poor bearing alignment or too tight adjustment. Wipe all surplus oil from the outside of the parts as it serves no useful purpose and may actually be detrimental because it will collect chips, dirt, etc. Wipe the ways over with an oily rag to make sure that tail stock and carriage move back and forth freely. Before attaching a face plate or chuck on the nose of the spindle all dirt should be removed from the threads on spindle as well as from female threads inside the chuck or in the face plate boss. The back of face plate or chuck should fit tightly against the shoulder at the end of the thread spindle nose. Before fitting the centers, drill pads or taper shank drills in the spindle and tail stock clean out the tapered holes thoroughly to remove all chips. A small chip will prevent the center from fitting properly and inaccurate work will result because centers are not in line.