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Do I Convert My Mill Or Buy a VMC? (CNC Mill Vs. VMC)

Choosing between a CNC mill vs. a VMC can be a task

The CNC mill vs. VMC debate is a never-ending one among machinists. And that’s for obvious reasons, as a milling machine post-CNC conversion and a VMC both offer you an upper hand in machining. 


As such, you’ll surely find the choice between a CNC milling machine and a VMC or vertical milling center as tricky. 


Converting your manual mill to CNC mill is an inexpensive way to get into doing production runs. 


Although manual mills can still be used once in a while in shops today, they’re virtually obsolete for production runs if you want to make a profit. If you’re a hobbyist on a budget or starting up a small CNC shop, a CNC conversion kit is your best bet. 


Here we summarize what it’ll take to convert to a CNC, how much it will cost, and how it compares to a vertical milling center (VMC). 

The basics of CNC Mill and VMC

CNC Mill Vs. VMC

Before we dive into the CNC mill vs. VMC debate, it’s important to understand the basics of these two machines. 


So let’s have a look at the two machine types and their functioning. 

What is a CNC milling machine? 

A CNC milling machine is very similar to a manually operated mill, the only difference being that the milling process is automated on the former. 


In fact, if you have ever worked on a CNC mill, you might have noticed that its processing equipment is developed very similarly to a manual mill. Also, the structure of a CNC milling machine, as well as its processing technology, is pretty much the same as its manual counterpart. 


Nevertheless, compared to non-CNC mills, a CNC mill offers unmatched precision and machining speed. That’s because cutting tools on such a mill are programmed and operated by computer numeric control, thus ensuring that the machine cuts, drills, or shapes a workpiece with utmost accuracy. 


Now, when it comes to having a CNC milling machine in your workshop, the most economical way is to get your existing manual mill converted to CNC. And the fact that CNC conversion kits with detailed step-by-step user guides are readily available means converting your mill is as convenient as buying one. 

What is a VMC machine? 

A VMC, or vertical machining center as it is also called, is a machine equipped with a rotating cutting tool for drilling/shaping metal pieces. 


As the name itself suggests, a VMC has machine tools oriented vertically and is primarily used for turning large and raw blocks of heavy metals like steel and aluminum. That means if you’re a machinist looking to mill large-sized metals, you can do so using a VMC. 


When we talk about VMC machines, it goes without saying that these are based on computer numeric control and, thus, fully-fledged CNC machines. And it is for this reason that a VMC machine is oftentimes also referred to as a CNC machining center. 


Further, a VMC machine is highly versatile in terms of machining operations it allows you to undertake, which include drilling, cutting, tapping, carving, chamfering, engraving, and more. 


Not to forget, VMC machines are quite cost-efficient for the features and capabilities they bring about in a machine shop. So it isn’t surprising why these machines are so much in demand among machinists looking to work on complex projects. 

CNC mill vs. VMC: What’s the difference?

While CNC mills and VMCs have much in common, given that they’re both essentially milling machines, there are things they don’t have in common. And it’s the different machining features that can help you choose between a CNC mill vs. a VMC and pick your ideal fit. 


Here’s how CNC mills are different from VMC machines: 


  1. First, a regular CNC mill is a three-axis machine since it has three axes, namely the X, Y, and Z axes. At the same time, you can have more than three axes on a VMC machine. Axes on a VMC machine typically range between four and five and even go up to twelve in industrial-grade machines.
  2. Second, a vertical machining center is equipped with an automatic switching device to continue processing workpieces non-stop and undertake multiple processes, something not common in all CNC mills. 
  3. The third and most noticeable difference between CNC mills and VMCs is that the latter can automatically change machine tools in the midst of operations. In fact, a VMC allows you to install multiple tools in one magazine, and that means you can do drilling, cutting, and shaping all in one setup. 

To Convert or Not to Convert your CNC mill? 

CNC mill

You can purchase a mill that’s already been converted or purchase a CNC conversion kit and build it yourself. Indeed, purchasing one that’s all set up and ready to go would be perfect.


However, you may not have so much cash on hand to spend all at once. This is why a lot of machinists end up purchasing the parts based on the funds they have.


If you’re willing to convert your manual mill to a CNC, we suggest you do a complete 3-axis conversion. 


While it’s more expensive, if you’re going to convert, you might as well go all the way. Being able to program the Z-axis moves besides the X- and Y-axis will promise shorter machining times. If interested, CNC Conversion Plus has the Grizzly G0704 CNC Conversion Kit, the Precision Matthews PM-25MV, Sieg X2 and X2D and others on offer.


So what would be the estimated total cost?


A mill converted to a CNC one will cost anywhere between $2,000 to $5000. The nicer and newer set-up will be more expensive.


Waiting for deals and shopping around may help lower the cost. However, you should still expect to end up within this margin for a mill that’s ready to go.

Purchasing a VMC vs. buying a CNC mill

CNC milling machine

While purchasing a VMC is more expensive in the majority of cases, these machines have better capabilities. 


Automatic tool changes, coolant, more horsepower, a lot sturdier, more rapid moves, and the list goes on. It really depends on how much you want to spend and how big of a machine you’re going for. 


While you can get a used CNC mill for $20,000, it will probably be more than 15 years old and will require substantial maintenance sooner rather than later. For another $10,000-$20,000 you can get a nicer and newer machine that will last longer based on how you use it and what sort of deal you get.

You should build/buy a converted mill if: 

  • You’re on a budget
  • You have time to convert it as time or funds allow
  • You’re just a home hobbyist
  • You want to DIY to save some bucks

Let’s have a detailed look: 

#1. Mill CNC conversion is budget-friendly

As you can see, a VMC machine can be an expensive affair, so much so that one can cost you between $30,000 and $40,000 on average. 


On the other hand, you can easily get a mini mill conversion kit and convert your manual mill to CNC for well under $1000. 


So, if you are a beginner or hobby machinist, or you own a small to a medium-sized workshop, converting your existing mill is a budget-friendly way to have optimum CNC milling capacity. 

#2. CNC mill needs time

Are you looking to have a CNC milling machine in an instant? 


If yes, then a mill CNC conversion project isn’t ideal for your needs. That’s because converting your manual mill to CNC either by yourself or by a professional call for time and effort. 


At the outset, you can expect anywhere between a week and a month’s time to entirely turn your manual mill to CNC. 

#3. CNC conversion projects are great for hobbyists

If you’re a hobby machinist looking for an interesting and engaging project to work on over the weekend or holidays, then CNC conversion is worth your time. 


Not only does such a project hones your skills, but you also gain CNC machining capacity at the end of it. 

#4. Mill CNC conversion kits are DIY-friendly

As a DIY person, you should definitely give a mill CNC conversion kit a shot, as these kits are highly DIY-friendly and come with detailed user guides. 


Want to undertake a DIY mill conversion project? 


You can go through our blog: A Comprehensive Guide To DIY Mill CNC Conversion

You should buy a VMC if: 

  • You want a sturdier, faster, more capable and powerful machine
  • You want to make it a business
  • You have a bigger budget
  • You have the patience to save up for one (if your funds currently don’t allow it)

Let’s have a detailed look: 

#1. A VMC is way more powerful than a regular CNC mill

VMCs are designed for large industrial-grade workshops and are capable of working on the biggest metal workpieces. Meaning, you can opt for VMC if a CNC mill capable of creating parts out of huge, bulky, and heavy metal pieces is your ideal machine. 

#2. VMC machines are expensive 

The features of VMC machining don’t come cheap, given that its heavy machining components cost a premium. As such, a VMC machine with more than three axes can cost you anywhere from $30,000 to upward of $100,000. 

Wrapping up the CNC mill vs. VMC conversation

There are benefits to purchasing either type of machine. While answering which one is better for your specific needs is difficult, we’ve laid out the reasons why you would or wouldn’t want to go a specific route. 


Feel free to call CNC Conversion Plus if you have any questions or if you’re looking for ball nut repair, or ball screw machining.


Also, you can reach out to us for CNC mills and lathes of all sizes, along with their conversion kits. 


We have the most extensive collection of turn key milling and lathe machines, as well as CNC conversion kits from market-leading manufacturers like Grizzly, Shop Fox, Little Machine Shop, and more. So whatever is your machining requirement, you can rely on us. 

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