Grizzly G0704 Benchtop Mill

A Complete Guide To Grizzly G0704 Mill CNC Conversion 

The Grizzly G0704 mill machine is the best candidate for CNC conversion

For any machinist looking to undertake a DIY mill CNC conversion project, the Grizzly G0704 is the ideal machine to go for. 


As a mini mill, the Grizzly G0704 milling machine offers heavy-machining capabilities thanks to its capability to drill, cut, and shape the hardest metals. So it shouldn’t surprise you when we say that this machine is the most sought after mill in the country. 


The Grizzly G0704 mill is a machine of choice, especially among small and medium-sized workshops, given the flexibility it offers to switch between materials. Not to mention the ease of changing cutting tools it offers, making it possible to instantly swap workpieces for machining. 


Moreover, what distinguishes the G0704 from other mini mills is the fact a simple DIY-friendly CNC conversion is possible. As such, you can convert a manual G0704 mill machine to CNC all by yourself. 


But before we move to CNC machining, let’s learn more about the Grizzly G0704 mill itself. 

The Grizzly G0704 mill machines: why does everyone love them? 

milling machine

The popularity of a G0704 mill machine among machine shops in the business of milling is no secret. And heavy machining apart, there are many other reasons why it is so preferred among machinists. 


First, this machine has a work area larger than mills of its size, along with a robust vertical square column. 


While the large work area on the G0704 expands your machining capability to include large-sized materials, a solid column keeps the mill stable while you machine heavy workpieces. 


Second, the mill works perfectly well, even as a manual machine. So much so that sophisticated drilling or cutting operations on this mill need less effort than their counterparts on the market. 


That means even if a CNC conversion is not on the cards for you, having a G0704 will only let you machine bigger and better pieces. 


In fact, it is for these reasons that the Grizzly G0704 benchtop mill is extensively imported by other sellers of milling machines and sold under various names. 


Interesting, isn’t it? 

Why convert the G0704 mill to CNC? 

Grizzly G0704 Mill CNC Conversion

The fact that a manual Grizzly G0704 mill works far more efficiently than other machines of its class might lead you to question the purpose of CNC conversion. 


However, it’s worth mentioning that no matter how well a manual mill functions, it can never match the level of precision, speed, and endurance that a CNC milling machine offers. 


So why not buy a brand new CNC machine, you may ask? 


To begin with, fully-fledged CNC mills can be very expensive upfront, costing you as high as $100,000 for an entry level machine. And even though such machines are the go-to for the larger players, for a small or medium workshop, that doesn’t make economic sense. 


On the contrary, you can buy a manual Grizzly G0704 benchtop mill together with its CNC conversion kit for well under $3500. Also, since the Grizzly CNC kit package includes all mechanical and electrical components necessary for conversion, you need not spend an extra penny. 


Further, a manual G0704 mill converted to CNC will function as good as a brand new CNC machine. Meaning, rest assured, you’ll have the same machining features and capability on your Grizzly G0704 CNC mill as any other CNC machine. 


Now that you’ve seen the advantages of converting a manual machine with a mill CNC conversion kit, you might well want to undertake a CNC conversion project. 


That’s exactly why we’ve detailed everything that you should know about a mill CNC conversion. So let’s have a look up close. 

What parts do you need for Grizzly G0704 mill CNC conversion? 

Grizzly G0704 Mill CNC Conversion parts

Turning a manual mill into CNC needs some specialized parts to enable computerized electronic control and functionality. And towards that end, two components, namely motor drivers and breakout board, are prerequisites.  


You’ll need the motor drivers to increase both speed and endurance of stepper motors. At the same time, a breakout board is essential for receiving inputs from the computer and turning it into signals for stepper motors’ motion control. 


You see, even as most Grizzly G0704 mills use a combination of high-performance NEMA 23 and NEMA 34 stepper motors, CNC motor drivers bring about precision control and increased strength. 


As such, with the trio of NEMA 23 on the X and Y axis, NEMA 34 on the Z axis, and CNC motor drivers, you will have enough capacity for milling heavy pieces. 


Next up comes the ball screws, which are needed to replace the Acme screws inside the milling machine. 


Acme screws are responsible for controlling the motion of the table. And once these are replaced with ball screws, you’re sure to have an incredibly smooth operation with almost negligible backlash. 


While it is still possible to convert your Grizzly G0704 benchtop mill by keeping the Acme screws, there are higher chances of backlash or motion loss during CNC milling. 


Moreover, as the Grizzly G0704 CNC conversion package includes double nut ball screws, there’s every reason to let go of the older Acme screws. That’s because the double nut ball screws go the extra mile to eliminate backlash during milling. Also, you can use these ball screws on bearings and motor couplers for optimum machining. 

Does CNC conversion on a Grizzly G0704 mill involve wear and tear? 

To enable CNC machining on your Grizzly mill, you do need to undertake some tear-off and reassembly. However, the tear-off and reassembly are quite basic, which means you can do so by simply following the user guide provided with the conversion kit. 


Usually, the Grizzly G0704 mill requires disassembly and reassembly for changing the old parts and retrofitting new ones during CNC conversion. And here’s what this process involves: 


The very first step in CNC conversion on any milling machine or lathe is disassembly, and while it may sound like a task, it isn’t very difficult. 


That also holds for the Grizzly G0704 milling machine, which includes the removal of the machine head consisting of different small parts, among others. 


Disassembly on a Grizzly mill involves pulling off the parts, starting right from the top and going up to the bottom. And that is done to ensure the old manual mill parts, which aren’t apt for CNC milling, are all removed and replaced with new ones. 


For instance, the Grizzly G0704 benchtop mill conversion process requires you to install new CNC capable ball screws and motor mounts. This is something that needs partial, if not complete, disassembly of the machine. 


Now, beginning with the disassembly, you first need to remove the Z-axis and then the X-axis. These two axes hold the machine’s work table on its lead screw. 


Also, both sides, i.e., Z and X axes, have a set of thrust bearings under their hand wheels which needs to be removed. 


Even though removing the entire lead screw seems like an easy and practical solution, it isn’t the efficient way since it will only make reassembly more complicated. 


Finally, you should remove the Y-axis, which controls the forward and backward movement of your milling machine. 


Once the machine has been disassembled and you’ve made the necessary changes and retrofits for CNC machining, you’ll have to reassemble everything back. 


However, before you begin assembling back the milling machine, you’ll likely need to modify the Y-axis area to make space for the new ball nuts on X-axis. 


Also, as the Y-axis ballscrew is the first thing to go into the mill, it needs the ball nuts to be removed. And that’s a complex process since ball nut removal can lead to bearings falling out. 


Overall, reassembling will follow the same process as disassembly, and you can do so by reassembling your machine from bottom to top. 

How to complete the conversion and enable CNC milling on your Grizzly G0704 mill? 

As you saw, to ensure effective CNC milling, the machine needs to be disassembled for mechanical retrofitting wherever necessary. Similarly, to bring about automation, you need to undertake electrical retrofitting on the machine. 


To start with electrical retrofitting, you’ll first need to install a stepper motor control system. It is the control system that transforms your machine from hand-operated to computer controlled, so we can’t overstate its importance for CNC machining. 


Thereafter, you’ll need to install a few electrical components like limit switches, probes, and a DC power supply. 


Next comes the control package for CNC milling, which should be compatible with popular CNC software on the market. As such, you should check the CNC control package before buying and make sure that it is compatible with the most popular software like GRBL, Mach3, or Linux. 

Don’t forget to retrofit your spindle 

Spindle retrofitting is essential for effective CNC conversion on your Grizzly G0704 mill. And to that end, you should convert your motor drive spindle to a belt drive system. 


Further, a VFD motor controller compatible with your spindle motor is essential to regulate and control your spindle’s RPM. 

Here are some things you should consider before undertaking CNC conversion on a Grizzly G0704 mill: 

Grizzly G0704 Mill CNC Conversion tips

  1. A CNC conversion project, notwithstanding the machine type and size, is usually a time-consuming process and can take between a week and a month to complete. So you shouldn’t expect a turnaround within days and be prepared to dedicate the required time. 
  2. Even though the Grizzly G0704 benchtop mill is small-sized and relatively lighter in weight, you should consider having at least one person to help you out. That’s because the mechanical components on this machine can still be too heavy, making disassembly and reassembly tough. 
  3. You should also have the required knowledge of various milling machine parts and their functions before disassembling the machine. That’s because a know-how of mechanical and electrical components makes it easy to disassemble or reassemble the machine. 
  4. It is essential to have the right safety measures in place while converting your mill to CNC since the process involves working with heavy mechanical parts and complex electrical wirings. 

The final word 

As a medium-sized milling machine, the Grizzly G0704 is apt for CNC conversion, given its heavy machining capacity and affordably priced conversion kit. Also, since the process of turning it to CNC is quite straightforward, this is the go-to machine for a DIY CNC conversion. 


Looking for a cost-efficient Grizzly G0704 benchtop mill and CNC conversion kit? 


You can reach out to us


At CNC Conversion Plus, we have the largest inventory of mill and lathe machines from industry-leading manufacturers, along with their conversion kits. 


Not a DIY person? 


Rest easy, as we’ve got your back. You can either send your manual milling or lathe machine to us, or we will buy one on your behalf. Our expert team of machinists will then convert your machine to CNC and ship it back to your workshop. 


That’s pretty simple, isn’t it? 


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