Wood Turning – THE LATHE
The sizes of turning lathes are given as 10″, 12″, etc. These figures denote the diameter, or size, of the largest piece of work that can be turned on them. The measurement is taken from the center point of the live center to the bed of the 
lathe (usually 5″ or 6″) and is one-half the diameter of the entire circle. The length of a lathe is determined by the length of a piece of work that can be turned.
CARE OF THE LATHE
The lathe should be oiled every day before starting. At the end of the period the lathe should be brushed clean of all chips and shavings, after which it should be rubbed off with a piece of waste or cloth to remove all surplus oil. All tools should be wiped clean and put in their proper places. If a student finds that his lathe is not running as it should, he should first call the attention of the instructor to that fact before attempting to adjust it; and then only such adjustments should be made as the instructor directs.
SPEED OF THE LATHE
The speed of the lathe should range from 2400 to 3000 revolutions per minute when the belt is on the smallest step of the cone pulley. At this speed stock up to 3″ in diameter can be turned with safety. Stock from 3″ to 6″ in diameter should be turned on the second or third step, and all stock over 6″ on the last step. The speed at which a lathe should run depends entirely upon the nature of the work to be done and the kind of material used.
Pieces that cannot be centered accurately and all glued-up work with rough corners should be run slowly until all corners are taken off and the stock runs true. At high speed the centrificial force on such pieces is very great, causing the lathe to vibrate, and there is a possibility of the piece being thrown from the lathe thus endangering the worker as well as those around him. After the stock is running true the speed may be increased.
TO FIGURE THE DIAMETER OF PULLEYS
Suppose a motor runs 1500 R.P.M. and is fitted with a 4″ pulley. Suppose also, a main shaft should run 300 R.P.M.
Then, 1500 : 300 :: x : 4;
Or, 300x = 6000,
x = 20, or the diameter of the large pulley on the main shaft.
Suppose again that a line shaft runs 300 R.P.M., and a counter shaft 600 R.P.M.
The counter shaft has a pulley 4″ in diameter. The pulley on the line shaft must
then have a diameter of 8″.
300 : 600 :: 4 : x;
Or, 300x = 2400,
x = 8″
Suppose the cone pulley on the counter shaft runs 600 R.P.M.; a lathe spindle runs
2200 R.P.M., when connected with the small cone pulley which has a diameter of
3″. The large cone pulley has then a diameter of 11″.
600 : 2200 :: 3 : x
Or, 600x = 6600;
x = 11″
43 Things Tags: Wood Turning, LATHE
