Feed mechanism of lathe

. the parts of the feeding mechanism

. functional features of the feeding mechanism


Feed mechanism

The feed mechanism of a lathe enables automatic feeding for the tool longitudinally and transversely as needed. By automatic feeding the finish on the work will be better, the feeding of the tool will be at a uniform by continuous rate and it takes less time to finish the operation while manual labour is avoided.


The feed mechanism comprises

Spindle gear

Tumbler gear unit

Fixed stud gear

Change gear unit

Quick change gear box

Feed shaft/lead screw

Apron mechanism

The proportionate tool movement for each revolution of work is achieved through all the above units of the feed mechanism.

Spindle gear

The spindle gear is fitted to the main spindle, and it is outside the headstock casting. It revolves along with the main spindle.

Tumber gear unit

The tumbler gear unit itself is of three gears, having the same number of teeth and  it contacts the  spindle gear to the fixed gear. It is also called the reversing gear unit as it is used to change the direction of feed of the tool for the same direction of rotation of the spindle. It can be engaged and disengaged with the fixed stud gear by  the operation of the hand lever provided in the unit.


The fixed stud gear

The fixed stud gear gets the drive from the main spindle gear through the tumbler gear unit and runs at the same number of revolutions per minute as the spindle gear  on most lathes.

Change gear unit

The fixed stud gear transmits its drive through a change gear unit to the quick change gear box. The change gear units has provision for changing the driver the driven and the idler gears from the set of change gears available for the purpose of  feed chaging as an additional unit.


Quick change gear box

The quick change gear box is provided with levers outside the box casting, and by shifting the levers, different gears are brought in mesh so that different feed rates can be given to the tool. A chart listing the different feed rates for the different positions of the levers is fixed to the casting, and by refering to the table, the levers may be engaged in position for the required feed rate.


The feed shaft

The feed shaft gets it drive from the quick change gear box, and through the apron mechanism, the  rotary movement of the feed shaft is converted into the linear movement of the tool.

The apron mechanism

The apron mechanism has the arrangement for transmitting the drive from the feed shaft to the saddle for longitudinal movement of the tool or to the cross slide for the transverse movement of the tool


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