How does drilling on a lathe work?

The drilling operation on a lathe is a type of machining by swarf removal in which the cutting movement is circular and which is characterised by the tool only being able to make a feed movement along the direction of the axis of rotation. This machining is carried out on certain types of lathe.

What is drilling on a lathe?

Drilling is a very common type of machining in metalworking that consists of cutting or piercing a workpiece by rotating a cutting tool called a drill bit. In drilling, machining is done by swarf removal, making a hole with perfectly defined edges. The hole can be made to suit the needs of the workpiece, changing its shape and diameter.

It is possible to carry out machining by drilling with a hand drill (for simple workpieces or one-off jobs), but it requires great accuracy and skill on the part of the operator; this machining can also be carried out using one of the many types of drilling machine that exist. Besides these two machine tools, some lathe models are equipped with a drilling function, since drilling is itself a turning operation, along with straight turning, facing, grooving, threading, and so on.

Drilling on a lathe is done when the workpiece has to be placed in an exact position on the drilling axis or when several machining processes need to be carried out on the same workpiece. For convenience, the workpiece is worked on a single machine tool capable of carrying out all the necessary processes.

Advantages of drilling on a lathe

Carrying out this type of machining on the lathe brings a number of advantages for workshops. First, the results of drilling on this machine tool are of high quality, with excellent and very accurate finishes. It also allows a reduction in production time and costs, because if the lathe uses CNC technology or computer numerical control, a small workpiece can be finished in a matter of minutes, since these machines are designed for series production.

In addition, labour is reduced, because operators only have to place the workpiece in the chuck of the machine and tell the machine's computer what job is to be carried out. Because CNC lathes are automated machines, the workpiece does not need to be changed in position or angle, since the lathe has the tools needed to position the workpiece according to machining needs.

For example, if you want to machine a workpiece of complex design, which has to go through several processes such as turning, milling and drilling, without a CNC lathe or a multi-function lathe the workpiece would have to be placed on three different machines and undergo three different procedures. On a CNC lathe, however, all the processes can be carried out, saving time and, of course, labour. That is why these machines are used in many industries ranging from metalworking to the making of artistic pieces.

The only drawback of drilling on a lathe is that it requires an operator experienced in designing workpieces. This is because, to get the most out of the machine and be able to carry out the different machining processes, correct programming is needed using CAD and CAM programs, together with proper translation into alphanumeric CNC language. Otherwise, neither production times nor production costs would be reduced.

Requirements for drilling correctly

Lathes that allow machining by drilling must have the tools needed for this function. The multi-function lathe, for example, is equipped with two spindles that alternate the tools needed automatically, but it is essential that the tools are the most suitable ones. For drilling, you need a drill bit. The type of drill bit varies depending on the workpiece to be machined; here you must consider the design, the type of drilling (shallow or deep), the diameter of the holes, the angle, and so on.

Drill bits are cutting tools and are cylindrical in shape with helical or straight flutes, ending in a conical tip, and are sharpened at a very specific angle. These tools are characterised by their diameter, shape and the materials they are made of.

It is very important to choose the right drill bit to obtain good results. For example, there are drill bits made of carbon steel and high-speed steel; the former are cheaper, but little used in industry because they wear out sooner, while high-speed steel drill bits are more common because of their resistance to wear and heat, as well as their use in machining at high cutting speeds.

Finally, to obtain good results from drilling on a lathe, it is important to know how to use the machine and to follow the manufacturer's recommendations. This is because the process produces large amounts of swarf or waste, so it is advisable to use the machine with precision and carry out proper maintenance to avoid unexpected production stoppages.