Horizontal Vs. Vertical Milling Machines: 8 Major Differences 

Picking between horizontal vs. vertical milling machines is easier than it looks

Throughout the history of milling machines, the horizontal vs. vertical mill debate has never abated on the market. 

Nonetheless, the fact that both are standard mills means you’re going to use them both for cutting, drilling, and shaping your workpieces. Also, be it a vertical or a horizontal mill, with the right kind of machine, you’ll surely be able to produce highly accurate parts. 

Not to mention, both manual, as well as CNC milling machine variants of these mills are readily available, and so are the mill CNC conversion kits. 

Then what exactly is the difference between the two mills, you’re sure to wonder? 

You see, the difference isn’t in the materials that these mills work upon but rather in the way they machine your parts. 

Here are some milling machine basics for a better understanding: 

A milling machine, unlike lathes, has a spinning spindle that cuts through the workpieces while the workpiece itself is clamped onto a worktable. 

Now, the spindle on a vertical mill, contrary to its horizontal milling counterpart, moves upwards and downwards. And that makes it ideal for tasks such as fabrication. 

What’s more to these mills? 

Let’s have a look at horizontal mill vs vertical mill machines, their working, and how they’re both different from one another. 

What is a horizontal mill? 

A horizontal milling machine is one with a rotating spindle mounted horizontally and running parallel to the surface. 

The cutting tools on these milling machine models are thicker yet smaller in size, as against the long and thin machine tools on vertical mills. 

And even though there are limits in terms of the workpiece varieties that you can machine on horizontal mills, these are capable of handling the heaviest of metal pieces. 

As such, with a higher horsepower and robust spindle, these mills will enable deep cuts on just about any metal, allowing you to undertake heavy-duty milling operations. 

Sounds impressive, doesn’t it? 

What can you use a horizontal mill for? 

A horizontal mill is very effective for machining tasks such as: 

• Boring, drilling, or tapping a horizontal surface.
• Cutting a slot.
• Cutting the grooves on a material.
• Cutting through a workpiece with multiple sides.
• Cutting or drilling through a heavy workpiece. 
• Creating complex designs and patterns, specifically on heavy metals. 

What is a vertical mill? 

The vertical mills are by far the most popular of all milling machine variants. And thanks to their versatility, they can machine the most extensive range of workpieces. 

As you might figure out from the name itself, a vertical mill has its spindle and cutting tools oriented vertically. 

The spindle on these machines holds spinning cutting tools using drawbars, while the spindle itself can have a vertical Z-axis movement with the help of a quill. In fact, the Z-axis movement of the spindle means that you can use one such mill as a drilling press too. 

Also, vertical mills have movable work tables with movement along the X-axis, Y-axis, and in some models, even the Z-axis. 

A vertical mill can have further sub-variants or categories depending on the functioning. That includes: 

1. A knee or turret mill 

Also called the Bridgeport-type mills, knee or turret mills have fixated spindles. Instead, the work table moves on the X-axis and Y-axis, and the knee has a vertical Z-axis movement. 

Further, a spinning spindle within the quill can provide you with additional Z-axis travel. 

Despite the small size of a knee or benchtop mill, they’re the most demanded machine among small-scale machinists, mini workshops, beginners, hobbyists, and more. That’s because not only is this machine type compact, but it is also customizable in terms of variable speed, work table size, etc. 

2. Bed milling machine 

Contrary to the knee mills, a bed mill is meant for large and, in some cases, exceptionally heavy workpieces. Meaning, one such mill has industrial applications and isn’t made for the smaller machine shops. 

Herein, the work table is moveable along the X-axis and Y-axis but not the Z-axis. Also, these mill variants have a moving spindle that lets you move the machine head and motor upwards and downwards along the Z-axis. 

What can you use a vertical mill for? 

A vertical mill is something that you can use for milling as well as drilling operations, thanks to its flexibility. And that makes such mills apt for industries and workshops of all types and sizes. 

You can, for instance, use a vertical milling machine for tasks such as: 

• Drilling, facing, boring, slotting, and within more such industries. 
• Metalworking, both big and small-scale. 
• Engraving, prototyping, and other similar custom projects. 
• Manufacturing gears, shafts, and other automotive components. 

Horizontal vs. vertical milling machines: what are the differences? 

Now that you’ve seen what vertical and horizontal mills are exactly, along with their sub-categories and applications, let’s go over the difference between vertical and horizontal milling machine.  

1. Spindle alignment 

A major and equally noticeable difference between a vertical vs horizontal milling machine is the way their spindles are aligned. 

To begin with, a horizontal mill has a spindle that runs parallel to the surface of the work table. And it performs machining tasks such as milling a workpiece by spinning on a horizontal center or column. 

On the contrary, a vertical milling machine has its spindle running perpendicular to the table surface. Herein, you can find the cutting tools rotating within the spindle to make a cut or drill, among others. 

2. Tool structure 

Both vertical mill vs horizontal mill have significantly different cutting tools or mill cutters, which also change the way they make cuts. 

If you’re someone who has used or seen horizontal mills, you may well have noticed thick and short tools. And these tools make the mill a great fit for cutting and shaping thick pieces of metal slabs. 

Talking about the tools on a vertical mill, they’re long and cylindrical. 

Even though a vertical mill’s cutting tools limit its ability to machine bulky workpieces, you’ll still find them handy for making precise cuts on lighter and smaller materials. 

3. Adaptability and all-round machining 

When it comes to undertaking multiple machining tasks on a single machine, the horizontal mill has its limitations. But that’s not the case with its vertical counterparts, which are way more versatile in comparison. 

How? 

First, not only can you use vertical turn key machines for milling purposes but also for drilling operations. And that is something you can’t expect a horizontal mill to do. 

Second, while it’s true that both mills can do facing and slotting, vertical mills take your machining experience a notch further by allowing you to make engravings, prototypes, etc. 

4. Level of precision 

Precision and accuracy are the mainstay of any machining operation, something nearly every mill machine manufacturer aims to achieve. 

So what about precision on a horizontal and vertical milling machine? 

The level of precision on a mill is determined to a great extent by the kind of cutting tools it is equipped with. 

On a horizontal mill, the thick and short cutters remain stable and allow you to make deeper cuts. So despite the limitations on materials that can be machined, you can actually make precise parts. 

Although vertical mills are known for their precision, their thinner cutting tools will cause a vibration when you make a deep cut. And that will affect the accuracy of the final component. 

5. Speed 

Another milling aspect that machinists are interested in is the speed at which each mill can remove materials. 

In terms of the rate of material removal, which ultimately decides the operational speed, horizontal mills fare better over vertical ones. 

In fact, the higher speed of machining is one of the reasons why many workshops and industries prefer them. 

A vertical milling machine, on the other hand, has a lower rate of material removal and, thus, lower speed. 

However, it’s worth mentioning that an individual machinist’s choice between horizontal vs. vertical milling machines isn’t influenced by speed. 

You see, vertical mills are highly sought after despite having lower speed, thanks to their ability to do sophisticated tasks. 

Similarly, horizontal mills are the machine of preference for more straightforward tasks on a bulky piece of metal. 

6. Customized manufacturing 

A lot of machine shop owners look to become proficient at making customized parts and components. 

But choosing between horizontal vs. vertical milling machines for custom machining can be tricky. That’s because both mill types allow you to make project-specific changes in one way or the other. 

Let’s see how a vertical and horizontal milling machine differ in terms of customization: 

A horizontal mill, as we saw earlier, has cutters parallel to the work area. And that makes it possible to reach the workpiece from multiple angles. 

Add to it the fact that you can install additional accessories depending on your machining requirements. 

Coming to vertical mills, they are ideal for complex cuts and designs, which gives them an edge over horizontal mills. Nevertheless, the design of the machine makes it less suited for installing add-ons. 

7. Chip evacuation

Chip evacuation is yet another important benchmark for mills, as it decides how much a machine needs to be maintained. 

On a vertical mill, the chips produced during an operation mostly remain on the machine’s surface. And the heat of the mill melts it over time, thus calling for more frequent maintenance and post-processing to avoid chances of machining flaws. 

Nonetheless, that’s not true for the horizontal mill that throws the chips away and doesn’t let them accumulate on the work table and other machine surfaces. 

8. Milling machine cost

In terms of price, the vertical mills, especially their benchtop variants, are way more cost-efficient than the horizontal mills. So much so that you can buy one for well under $2000. 

Nevertheless, the large bed mills under the vertical mill category can be expensive since they’ve large-sized components and are meant to machine industrial-grade workpieces. 

Horizontal vs. vertical milling machines: FAQs

What are the advantages of a horizontal mill? 

A horizontal mill fares better over its vertical counterparts in many ways, such as: 

1. Due to the shape and orientation of the spindle and the cutting tools, they’re more stable no matter how deep a cut you’ve to make. 
2. Horizontal milling machines offer faster machining thanks to their higher rate of material removal. As such, you can easily scale your operations with one such mill. 
3. When it comes to a horizontal milling machine vs vertical milling machine in terms of chip evacuation, the former fares better. That’s because the small metal chips don’t melt and stick to the various components of the horizontal machine. As a result, upkeep requirements are considerably lower on horizontal mills. 

What are the disadvantages of a horizontal mill? 

There are various drawbacks to horizontal mills, which include: 

1. In comparison to vertical mills, more so the turret mills, horizontal milling machines are way more expensive. And it is for this reason that you’ll mostly see in the bigger workshops and industries. 
2. Talking about the availability of a vertical vs horizontal mill, there aren’t many horizontal mills on the market, which also goes for their machine operators. So machine shops have a hard time hiring a trained machinist for horizontal mills. 

What are the advantages of a vertical mill? 

A vertical mill is best suited for beginners and small to medium-sized workshops owners for reasons such as: 

1. Compared to their horizontal counterparts, vertical mills are more readily available on the market. In fact, these are the most selling mills on the market, so you can easily find one that suits your needs. 
2. Availability apart, the vertical mills are also highly cost-efficient, meaning there’s always a mill on your budget. 
3. Vertical mills are simple to operate, so you need not be a seasoned machinist to operate one. All you need to do is follow the user guide and go over some tutorials. While the quality of machined pieces won’t be optimum for beginners, you can easily hone your skills over time. 

What are the disadvantages of a vertical mill? 

The drawbacks of vertical mills include the following: 

1. The rate of material removal is lower on vertical mills as compared to their horizontal counterparts, which reduces machining speed. So, if you’re looking for faster production, this may not be ideal. 
2. A vertical mill can’t make deep cuts, and that limits the scope of operation of such mills. 

The final words 

The debate on horizontal vs. vertical milling machines between the machinists is least likely to be over anytime soon. But that doesn’t mean you’re going to have a hard time choosing one between them.

You see, each of the two mills has its own specifications and is suited for a certain kind of machining. And that means you can easily pick one from them once you’ve sorted your operation type. 

Also, both horizontal and vertical milling machines can be converted to CNC milling machines with a CNC conversion kit. So no matter the kind of mill you’ve, you can always scale its capability and improve your work quality with CNC conversion.

Looking to choose between a horizontal vs vertical milling machine?

You can reach out to us!

At CNC Conversion Plus, we have top-of-the-line vertical and horizontal milling machines and also CNC conversion kits compatible with every mill. Also, we can assist you with choosing the best machine for your workshop. Meaning whatever be your requirements, we’ve got them all covered.