9 Milling Operations You Need To Know

Milling might seem straightforward at first—stick a block of metal under a spinning tool and shape it—but there’s a lot more to it than that. Just like turning on a lathe, understanding the different milling operations can help you get better finishes, reduce cycle time, and even extend tool life.


This post is a follow-up to our 10 Turning Operations You Need To Know on a Lathe. If you’re new to the world of mills and cutters, this one’s for you.


What is Milling, Really?

Milling is a machining process where a rotating cutting tool moves over or through a workpiece to remove material. Unlike turning, which is usually done on cylindrical parts using a lathe, milling is more versatile—perfect for flat surfaces, irregular shapes, slots, pockets, and more.

With that out of the way, here are 9 common milling operations every machinist should know:


1. Face Milling

What it is: Face milling uses a tool with cutting edges on the face and sides to create a flat surface perpendicular to the spindle.

When to use it: Great for squaring up stock or machining a clean, flat reference surface.

Tool example: Face mill cutter, typically with multiple indexable inserts.


2. Slot Milling

What it is: A milling operation that cuts a straight groove into the material.

When to use it: When you need to machine keyways, channels, or T-slots.

Tool example: End mill or slotting cutter, depending on slot width and depth.


3. Side Milling

What it is: Cutting along the side of the tool to machine vertical surfaces.

When to use it: For creating shoulders or steps on a workpiece.

Tool example: Straight tooth side cutter or standard end mill.


4. Pocket Milling

What it is: Removing material from inside a closed boundary, like a cavity or pocket.

When to use it: For features like cavities in molds or pockets for fasteners.

Tool example: Flat end mill, sometimes combined with helical ramping.


This post is a follow-up to our 10 Turning Operations You Need To Know on a Lathe. If you’re new to the world of mills and cutters, this one’s for you.


5. Profile Milling

What it is: Contouring the outer edges of a part.

When to use it: For irregular part shapes or precision outlines.

Tool example: Ball nose or flat end mill, depending on the required surface finish.


6. Drilling with End Mills

What it is: Using an end mill to plunge into material vertically.

When to use it: For starting holes, angled surfaces, or when a drill can’t reach.

Tool example: Center-cutting end mill (important—it must be center-cutting!).


7. Helical Interpolation

What it is: A combination of linear and circular motion to mill circular features or bores.

When to use it: When you don’t have the exact drill size or need tight tolerances in a bore.

Tool example: End mill with CNC programming support.


8. Surface Finishing Passes

What it is: Light cuts taken after roughing to achieve the desired surface finish and dimensions.

When to use it: Always—unless you love sanding parts by hand.

Tool example: Same end mill as roughing or a dedicated finishing tool.


9. Chamfering & Deburring

What it is: Machining angled edges or removing sharp burrs.

When to use it: To clean up part edges, improve safety, and prep for assembly.

Tool example: Chamfer mill, spot drill, or even a countersink tool.


10. Thread Milling (Bonus!)

Okay, we said 9—but here’s a bonus.

What it is: Creating threads by milling in a helical path.

When to use it: When flexibility is key—same tool can make different thread sizes.

Tool example: Thread mill.


This post is a follow-up to our 10 Turning Operations You Need To Know on a Lathe. If you’re new to the world of mills and cutters, this one’s for you.


Wrapping It Up

Understanding these milling operations gives you a leg up whether you’re programming a CNC or running a manual mill. Picking the right operation—and the right tool—can save you time, money, and a lot of frustration on the shop floor.

We at Turntech Precision provide the top quality parts machined on the Swiss-type lathes utilizing turning, facing, grooving, threading, knurling, boring, and tapping operations. We work closely with our customers to provide them with the best solution to their engineering problems in a variety of industries. Contact us today with your inquiries.