What is a Fly Cutter on a Milling Machine – Fly Cutter Definition, Types, Uses & Fly Cutter vs Face Mill


The machine and cutting tool you use in CNC milling will influence the surface finish of the final parts and the machining speed. Depends on your purposes, there is a broad range of milling cutters can be selected. What is a fly cutter on a milling machine? In this article, we are going to introduce the fly cutter involves its definition, types, uses, and fly cutter vs face mill, what’s the difference between them.

What is a Fly Cutter?

A fly cutter is a single-point rotary cutting tool primarily used on a milling machine for machining large and flat surfaces. The fly cutter is composed of a body into which one or two tool bits are inserted. Most fly cutters are available with a holder, drawbolt, thrust washer, and a left-hand carbide cutting tool. Most fly cutters simply have a cylindrical center body that holds one tool bit. It is usually a standard left-hand turning tool that is held at an angle of 30 to 60 degrees. Fly cutters with two tool bits often with a tool bit fastened on each end. These bits will be mounted at right angles to the main axis of the bar stock. Each tooth of the cutting edge requires more power from your machine, so multi-toothed cutters on the small machines do not always work well because of a lack of rigidity and power. If you are running a light-duty mill, you can probably get the best performance from a single tooth cutter. Fly cutters are often mounted in a special angled holder, when the entire unit rotating, the tool bit takes broad and shallow facing cuts. Fly cutters are similar to face mills because they both designed for face milling and their individual cutters are replaceable. But they are different in many other aspects. 

Fly Cutter Types

Fly cutters can be designed and manufactured to meet specifications in most industries. There are many types of fly cutters, such as point cutters, rotary carving tools and rotary cutting tools. 

– A point cutter comes with a needle-style point to cut densely populated corals, it can go to the hard-to-reach areas and the precision ground edges allow a precise and clean cut every time. A point cutter has two cutting edges per blade. The blade is similar to 1/3 of a rotary blade. It slips in and out of the handle for safe storage. Both long and short sizes are available. 

– A rotary carving tool is usually used to carve on hard materials like wood, blown glass, and even carve through the grain. 

– A rotary cutting tool used to cut all fabric types up to eight layers quickly and easily without changing the patterns. 


A rotary tool accessory consists of a variable speed motor for smooth operation with speeds of up to 30,000 rpm. The main body of a rotary tool has a spindle lock to allow opening and closing the 1/8 inch collet so as to fit standard rotational tools. 

What is a Fly Cutter Used for?

Fly cutter is a type of cutting tool of machine tools, can be used in CNC machining centers and manual mills without the use of additional arbors, fly cutters are often utilized to remove large amounts of metals and level it, even though the tool is used for a long time, you can re-sharpen it by straightforward grinding.


The fly cutters can work in several ways. A normal fly cutter can be adjusted to cut up to 2-inch diameter and a 0.01-inch deep cut in aluminum at this diameter. A rotary tool is ideal for cutting, carving, sanding, drilling, and grinding. 

Fly Cutter vs Face Mill

Either a fly cutter or face mill can be used to machine the face of a plate, what’s the difference between fly cutters and face mills? 

1. Fly cutters tend to be cheaper than face mills. Large face mills and their inserts are expensive. 

2. Face mills use multiple inserts, which allows removing more materials at higher speeds, a fly cutter only uses one insert, which is not as fast as face milling but offers a more uniform and smooth surface. 

3. The fly cutter is a better choice for the skim cut with large width and special profile requires the tool to possess, face mill is suitable for heavy removal. 

4. A fly cutter will run and give good results on less weighty, less powerful machines, but with a lower metal removal rate. A face mill requires more power and more rigidity than a fly cutter of the same diameter.

5. Face mills are more ideal in rigidity, indexability of inserts without disturbing effective cutter diameter or tool length offset, and depth-of-cut capability.

6. A fly cutter will produce a very flat surface with proper setup, the cutting edge can cover a large surface in one pass, a face will produce a more ridged surface as its cutting edges are not at the same height.