Discover how a parallel lathe works, an essential machine

Descubre cómo funciona un torno paralelo, una máquina indispensable

The parallel lathe is a machine, also considered a tool, that allows transforming the dimensions and shapes of any solid piece . This transformation process is achieved thanks to the rotation of the solid piece around the symmetrical axis of the desired shape, removing the material peripherally and in the form of a chip. This is how a parallel lathe works.

Heller lathe

How does a parallel lathe work?

The parallel lathe system is based on a headstock in which a spindle rotates, two parallel guides , one longitudinal and one transverse to the spindle. The universal plate is installed on the spindle shaft (it can be a smooth plate or with three or four jaws). They serve to adjust and center the part to be machined and indicate the turning movement that the electric motor will perform.

The parallel lathe is one of the most useful and used machine tools in the industry . Among the advantages of the parallel lathe we can highlight its easy handling and versatility, since its pieces can be prepared in a short time and easily. This machine is used to execute an endless number of jobs with maximum effectiveness such as:

  • Cylindrical turning
  • Countersigned
  • Conical turning
  • Thread cutting
  • Chopped
  • metal cutting
  • Shape cutting

What are the parts of a parallel lathe?

The parallel lathe is made up of 4 parts : head assembly, bed, carriage and tailstock assembly.

Head assembly

The piece is permanently attached to the bed in the left area of ​​the lathe. It also includes the head spindle, which rotates with the help of pulleys. The function of the spindle is to center the target piece and make it rotate . The precision of lathe work depends on the rotating axis of the spindle that centers the piece, which must be manufactured with all possible care.


It constitutes the base of the lathe and is the part in charge of supporting all the elements that make it up . The quality of the guides depends on the construction materials used by the manufacturer. In this sense, the most economical lathes are distinguished by having less reinforced or non-hardened guides.

Linear guides that are replaceable can be found on the market, while other manufacturers use hardened cast guides that are essential in the bed.


It is the part in charge of controlling the cutting tool and is made up of 5 different parts:

  • Board attached to the carriage support : it is suspended in the front part of the bench
  • Cross carriage support : this cast piece slides on the guides and adjusts to the bed
  • Composite support : located on top of the cross carriage
  • The cross carriage : it is located above the main carriage
  • The post for the shim and washer , which slide into a T-shaped slot on top of the bracket
Lathe protection

Safety elements of the parallel lathe

The parallel lathe has a transparent protection and a microswitch that are used preventively against projections, and with buttons that allow emergency stops , etc. In addition, the machine's belts, pulleys and sprockets are protected with guards.

Preventive measures for the use of the parallel lathe

Now that you know how a parallel lathe works, before starting the turning work, it is very important to carry out the following checks:

  1. The machine must be connected to a differential switch with its corresponding ground point. Furthermore, it is advisable that the protection layers of the transmissions and gears have switches installed in series, since this prevents the lathe from starting when the protective casings are not closed.
  2. The piece to be turned must be in a correct position and well supported so that its movement has no obstacles.
  3. The plate and safety must be correctly positioned .
  4. Make sure the retaining screws are tight.
  5. Remove the plate adjustment key .
  6. The locking lever must be securely locked .
  7. The transparent chip protection screen must be properly positioned .
  8. If the turning work is carried out on long bars, it must be checked that the bar is completely covered by a guide protection.
  9. If a tailstock is incorporated in the turning process, confirm that it is well anchored to the bed and that the lever that locks the spindle is well adjusted.
  10. Check that there are no tools or pieces left on the lathe that could be thrown off in the process.
  11. The protective cover of the plate must be securely in place .
  12. During turning, the person in charge must stand safely and as far away as possible from the rotating parts. Hands must be kept on the handwheels of the parallel lathe and never on the bed, tailstock, carriage, or on the workpiece.
  13. All check measures must be carried out with the lathe turned off , especially the following:
  • Tool change
  • Piece clamping
  • Cleaning
  • Finish measurement
  • Coolant status (lubricant/coolant)

All of the above information is applicable to all lathes, but mainly to manual or conventional lathes. CNC lathes, working automatically once programmed, must and usually have complete closed fairings and do not operate until the door is completely closed, allowing for much safer machining operations.