Drill Press Mill Conversion

Drill Press Mill Conversion: A Complete Guide For 2023

A drill press mill conversion is the most cost-efficient way of owning a milling machine

For hobbyists on the lookout to acquire a small budget mill, a drill press mill conversion is not only affordable but an exciting DIY project too. 


While buying a brand new mill is ideal for most machine shops and also something we suggest to workshop owners, that doesn’t always apply to hobbyists. 


Wondering why? 


You see, first of all, many hobby machinists lack the upfront investment that a new mill calls for. And cost apart; most hobbyists simply don’t need the superior features of a fully-fledged mill. 


As such, repurposing and using a drill press as a mill makes both economic and logistical sense. 

But why should you be using a drill press as mill in the first place? 

drill press to milling machine

Well, a drill press is, without doubt, the only machine that closely resembles a mini mill. In fact, if you look at a drill press, it’s hard to tell the difference at first glance. 


Of course, a drill press and a milling machine are entirely different when you go into the way they are built and the kind of operations they support. 


Nevertheless, building a turn key milling machine out of a drill press is possible. And the best thing is that the entire cost of a drill press to mill conversion kit, including a used drill press, falls way below $500. 


Meaning you need not shelve a big fat cheque for having a hobby or beginner-level mill in your workshop. 


Furthermore, complicated as it may sound, turning a drill press to milling machine is actually very easy. So much so that you can undertake a DIY drill to mill conversion project and complete it within days. 


Now, that’s impressive, isn’t it? 

How to convert a drill press to a mill? 

drill press to mill conversion kit

Now that you know using a drill press is the best solution to build your own mill at a shoestring budget, you might wonder how exactly you can do so. 


To begin with, you’ll need a drill machine, the most critical gear in any drill to mill conversion kit


Herein, you don’t need a brand new drill press, as a functional pre-owned machine should be fine. Also, such drill presses are readily available on websites like eBay for well under $200. 


We suggest you can buy a Harbor Freight 8″ or a Walker Turner 900 series drill press for the task. That’s because these drill presses are cost-efficient and easy to work with. 


Coming to drill press conversion, it’s a technical process that requires the right tools and steps. So let’s have a look into the steps involved and the tools needed for a drill press mill conversion. 

Step #1. Opening the drill press and basic mill setup 

The first step in converting your drill press to milling machine is opening the drill. And to do so, you’ll have to unscrew and separate every part of the machine on a work table. 


But why to open up the drill press, you may ask? 


Opening the drill is essential since it allows you to understand its various components and how each of them works. 


For instance, you’ll commonly find parts such as the spindle supported by a couple of roller bearings. Also, a drill press spindle has a taper on one end and is splined on another. 


Similarly, you’ll also find a secondary shaft that is supported by ball bearings and used to hold the belt drive pulley. 


Now, you’ll need a collet with cutter holding capacity to start the drill to mill conversion process. And for this purpose, you can find low-cost yet highly effective E20 collets on the market. 


Since the E20 collets have a 12mm hole at the center, you’ll need to shape the spindle taper to be able to fit it into the collet. 

Step #2. Picking the right ball bearings

You’ll agree when we say that ball bearings are one of the most critical components of your mill. So when it comes to supporting all kinds of loads plus reducing friction, we can’t overstate the importance of the right ball bearing. 


While the drill has pre-installed ball bearings, they aren’t necessarily ideal for supporting the operations of a mill. That’s because such bearings are placed with the functionality of a drill press in mind. 


As such, we suggest you replace the existing ball bearings with those that can support both higher loads and increased RPM. 


For instance, the 6201 and 6203 ball bearings come with maximum feed rates of 14,500 and 11,000 RPMs, respectively. Also, both bearings have load capacities of 1550 and 2100 lbs, respectively. Meaning one of these bearings should be apt for your new converted drill mill. 


However, it is always better to factor in your own unique requirements before settling for milling machine bearings. 

Step #3. Installing the right work table 

As a matter of fact, milling machines, notwithstanding their size, do need a large and solid work table.


Even the hobby milling tasks are more complex and diverse than standard drilling operations. Thus, you can’t expect the drill press table to come in handy for your needs. 


Thankfully, like all other components, the work tables on drill machines are replaceable too.


Furthermore, machine tables to support the needs of beginner machines are available for anywhere between $150 and 200 on average. 


So all you’ve got to do is pick the right milling machine grade work table and replace the drill table with it. 

Step #4. Adjusting the quill 

The quill on a drill press moves the way very fast, something not desirable on a milling machine.


So you’ll have to adjust the quill to an extent where the movement of the way aligns with the standards of a mill. And you can do so by turning the end of the existing quill to around 16 mm.


Thereafter, you can bore a brass gear, again by approximately 16 mm, and then integrate a set crew to it. 


This way, the speed should perfectly come in sync with that of a standard mill. Also, this will create a z-axis movement of roughly 2.5 mm for every shaft rotation. 

Step #5. Adding a spindle lock

A spindle lock is quintessential for any mill machine, including the drill mill you’re about to create. That’s because not only does it check the spindle movement while you’re cutting a piece but also provides the much needed rigidity during operations. 


To install a spindle lock on your drill mill, you can remove the grub screw from the machine and simply replace it with a spindle bolt. 

Bonus Step #1. Simply buy a milling attachment and complete the drill press mill conversion in no time

Thinking how not to get bogged down by the complex process of drill press mill conversion? 


Well, you can get a milling attachment and integrate it into your drill press hassle-free. 


There are various milling attachment models available both online and offline. So you can buy one that meets your machining criteria and install it onto your drill press by following the user manual. 


In fact, some milling attachments allow you to retain the drilling features of your drill mill while using it as a milling machine. 

Bonus Step #2. Convert your drill mill to CNC and get the best of automation

using a drill press as a mill

As you might be aware, CNC machining has come to change the way we machine our workpieces. 


While automation was only a thing of the larger industries, it’s now evident in the smaller workshops, including the hobby mills. And for good reasons, since CNC mills and lathes offer unmatched accuracy and scalability. 


So why not convert your drill press mill to CNC? 


You see, even though buying a brand new CNC machine is too expensive upfront, that’s not the case with a CNC conversion kit. That’s because you can get one such kit for well under $1500. 


Further, when it comes to turning a drill press into a CNC mill, using a conversion kit, it’s a highly DIY-friendly process. So much so that using a CNC mill conversion kit is way easier than using a drill press to mill conversion kit. 


Meaning you can convert your drill mill to CNC within a few days after converting your drill press to mill, that too at zero labor costs. 


Sounds awesome, doesn’t it? 

Wrapping it up

As you can see, owning a hobby mill need not break the bank, thanks to easy drill press mill conversion techniques. Also, you can have top-notch CNC machining features at just a little additional expense. 


Looking to get one such drill press mill machine built? 


You can reach out to us!


At CNC Conversion Plus, we are known for building high-end custom mill and lathe machines. All you need to do is tell us about your needs, and we will build a machine tailored to your requirements. 


Also, we have a large inventory of mill and lathe machines, along with their CNC conversion kits, readily available for pan-American shipping at the most competitive prices. 


So wherever your machining requirement is, we’ve got them all covered. 


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