Essential Lathe Cutting Tool Types for Precision Machining

A lathe is one of the more versatile types of cutting machines available for small and large-scale machinists today. One of the keys to that versatility is the wide range of cutting tools a lathe can be equipped with. In this article, we’ll take a quick look at some of the different categories of lathe cutting tools, as well as some other tools worth mentioning on their own.

Five Main Categories

External Turning Tools

Turning tools are your most basic lathe tools; they remove a maximum amount of material with minimal effort. Ok, not minimal effort – this is a high-powered piece of machinery after all. Rough turning tools remove large amounts of material in order to shape the workpiece. Finish turning tools are finer, and leave a smooth, highly-polished surface.

Drills

If you need to create a hole in a workpiece, you use a standard drill or a radial drill. It’s nearly always the first stop – either a drill or, in some cases, a boring bar (more on that next). A drilling tool on a lathe is much the same as the drill bit on a common hand-held drill, except that in this case it’s the workpiece that is spinning, while the drill remains stationary. The function remains the same – create a rough hole, which can be finished out or threaded as needed.

Boring Bars

Boring bars are used to create a rough-edged hole, or, depending on the exact tool used, to finish out an existing hole. If used to create a hole in the first place, boring bars are often used in conjunction with the next category of tools on this list: threading tools.

Threading Tools

This is one of the largest categories of lathe tools. There are tools for cutting square threads, large threads, and small ones. There are tools for cutting internal threads, like the inside of a nut, or external threads – the ones commonly found on bolts, screws, etc. Countless variations exist – all of them are considered various kinds of thread cutting tools.

Parting Tools

Parting tools can “part,” or separate, a workpiece – a slightly fancy way of saying that they cut parts. But that’s not all a parting tool can do; machinists also use them to cut grooves, create shoulders and beveled edges, and to smooth off cut faces for accurate measurement. Despite the simple name, parting tools are actually among the most commonly-used lathe tool types.

Other Common Tools

These tools are different members of the categories mentioned above, rather than new categories. But it’s worth mentioning what they’re used for and how they work.

Chamfer and Shoulder Tools

A chamfer is an intermediary face, or sometimes an angled face to a workpiece. A shoulder tool cuts a “step” into the workpiece. Shoulders can be beveled or straight, depending on the exact angle of the tool used. 

Facing Tools

Machinists use facing tools to cut a workpiece to the desired length. Going a step further, facing tools are designed to leave a smooth and accurate surface so that the operator can take an accurate measurement. Facing tools are used for both rough and finishing operations at the same time.

Forming Tool

If a part requires an unusual shape, one option is to use a forming tool. They are typically fed directly into the workpiece, thus leaving a mirror reflection of the forming tool in the piece. Commonly-used shapes include grooves, dovetails, threads, etc. 

Lathe tools are nearly-infinite. Even a single category, such as threading tools, can include thousands of pieces; large threads, small ones, internal, external, tight patterns or looser spirals. Part of the versatility of a lathe comes from the fact that you can use a lathe to make more parts for the lathe.

Once you’ve mastered the machine a bit, you can build the solution to any potential problem, and give yourself another tool for your inventory. But whatever tool you need and whether you build it or buy it, most of the tools you use will be one of the types discussed here.