Are you thinking about buying a used milling machine? Many business owners, home machinists, and hobbyists prefer a used milling machine because a new one is out of their price range. Fortunately, a carefully chosen used machine tool will get the job done efficiently and save you lots of money.
However, buying a used CNC milling machine or manual Bridgeport-type vertical knee mill is a significant investment. Before making the purchase, there are some essential factors to consider, and let’s look at ten of those factors individually and in more detail. But first, let’s determine which type of milling machine you need.
You Will Likely Search Among Six Types of Used Milling Machines
Depending on the type of milling you will be doing, you will probably choose from the following:
- Vertical milling machine: Vertical milling machines are used for machining flat surfaces, grooves, and slots. The table moves up and down and feeds in the X-axis and Y-axis (left-to-right and in-and-out).
- Horizontal milling machine: The spindles are horizontal, and the machines are sturdier with a horizontal milling machine. The horizontal spindle requires different types of tooling compared to the vertical milling machine.
- Bed type mills: The bed mill differs from the vertical knee mill in that the bed mill’s table is fixed on the Z-axis, while the knee mill’s table moves up and down on the Z-axis.
- Turret milling machines: Bridgeport-type milling machines or vertical knee mills are pretty versatile and can perform various operations.
- Universal milling machine: The universal milling machine can perform various operations, especially if you add a rotary table or dividing head. Operators can pivot the table 45 degrees from both sides for even greater versatility.
- CNC milling machine: CNC milling is a process using a cutting tool on a rotating spindle to remove material from a workpiece mounted on a working surface or in a vise. A multiple-axis CNC can create complex shapes without moving the workpiece to another machine tool for secondary operations.
Should You Buy a Brand Name Such as Bridgeport or Cincinnati?
Brand names influence many purchasing decisions, but how much do they matter? You might recognize words like Acer E-Mill 3VKH, Bridgeport Series I and Series II, the Cincinnati Horizontal Milling Machine, or one of the Seiki brands of CNC machine tools.
You’ll also run into brands you don’t recognize: Acra, Trak, Lagun, and Kearney & Trecker, for example. You might prefer a used milling machine manufactured in the U.S. over one made in Taiwan, for instance. In theory, any manufacturer might design and manufacture quality machines, so you should be careful not to eliminate a machine using the wrong criteria.
Although a used milling machine brand that withstood the test of time has the best chance of being a respected brand, don’t pick your next used milling machine solely on its brand name. There are many more factors to consider including the machine’s features, its warranty, and overall condition. Let’s look at the various factors that typically indicate if the machine tool will fit your requirements, give you value, and then choose. Here we go:
1. What is the Machine’s Table Size?
Maybe a used desktop milling machine is all you need for your operations, but size matters if you intend to machine large metal parts as part of fabrication or repair work. Your working surface must accommodate the largest workpiece you anticipate, so make sure you choose a heavy-duty machine with the appropriate table size.
2. Should you consider a CNC Conversion Kit?
Whether used or new, purchasing any CNC machine is a big investment. However, almost anyone with a compatible milling machine who wants to give their machine features found in CNC machines can use a CNC conversion kit.
A conversion kit can help reduce costs even further, extend the lifespan of your mill, increase production, and provide additional safety. For specific information, please make sure to contact us before purchasing a conversion kit.
3. Does the Used Milling Machine Have Power Feed on the Longitudinal (X-axis)?
It would be a bonus if each axis had a power feed, but it is essential to have it on the X-axis if you plan to do slotting or surface milling. You don’t want to be cranking a handle for hours when you can have a power feed doing the cranking.
4. Is it Equipped with an Acu-Rite Digital Readout (2-Axis DRO)?
You can add a digital readout to the X-axis and Y-axis later, but it would be better if the used mill already had a DRO. A DRO provides a display telling you the distance you moved the table. And even though they aren’t necessary, DROs are far superior to the time-consuming process of reading the dials on the machine.
5. Do You Need a Mill That is Also a Drilling Machine?
If you need a used milling machine that serves as a drilling machine, you have narrowed down your choices. It is your best option if the turret milling machine, a.k.a. the Bridgeport-type vertical knee mill, covers all your other requirements. These versatile machines can perform various operations when you clamp the workpiece directly to the table using the t-slots or by fastening a vise to the working surface and holding smaller pieces for milling or drilling.
6. Does the machine tool run on single-phase or 3-phase power?
You probably don’t have 3-phase power at your home, so if you’re buying the used milling machine for your home shop, you’ll be limited to machines that can run on standard household power. However, if you have industrial space with 3-phase power available, you can search for an industrial-grade machine. Or, if you find a 3-phase machine for your home shop, you can replace that spindle motor with a single-phase unit or buy a phase converter.
7. Does the Used Milling Machine Have the Spindle Speeds You Require?
If you are machining materials like aluminum, soft metals, wood, or composites, make sure that you choose a machine with variable speeds with higher spindle speeds optimal for that type of work. A high-speed head could make the difference between buying or moving on to the next mill.
8. Does the milling machine have a warranty?
Buying a used milling machine is an investment. Lightly used machines may have a nice discount, but what about a warranty?
Not all manufacturers will include one, but buying a machine under warranty or obtaining a warranty is a great way to protect yourself in the event the machine has unknown issues.
9. What are the Longitudinal, Saddle, and Knee Travel Limits?
Investigate the travel limits of the longitudinal (X-axis), saddle (Y-axis), and knee travel (Z-axis) to ensure the machine tool can cover the dimensions of a typical workpiece. Otherwise, you’ll spend too much time unclamping and moving the material to reach the entire work surface. If you’re looking at a Bridgeport-type vertical milling machine, remember you’ll have a moveable ram and a turret that swivels to cover even more of the workpiece.
10. Do You Want to do CNC Milling, or is a Traditional Manual Machine All You Need?
If you want or need a CNC vertical or horizontal milling machine with CNC control, now is the time to decide. A quality used Bridgeport Series I vertical knee mill might have everything you need if you’re mainly doing repair or jobbing shop work. On the other hand, if you’re hoping to get into production work or complex parts, the CNC milling machine is the way to go, or you should give it serious consideration.
Bonus: How will you receive your CNC machine?
If you’re buying online from a trusted CNC machine company, chances are they’ll arrange to ship. But some CNC machines are quite large. And even if the machine is picked up in your local area or state, you may need to hire a heavy equipment shipping company to bring the machine home.
You Could Buy a High-Quality New CNC Milling Machine for Not Much More Than a Used Milling Machine?
The professionals at CNC Masters believe you should be able to have a CNC milling machine or lathe without destroying your budget. After you have determined the features you want in a used milling machine, check out our lineup of new machine tools you could add to your shop. All of these machines will provide you with all power and versatility you’ll need to take your business to the next level.
All CNC Masters machines are made in the USA and backed by our one-year limited warranty, so it’s a brand you can trust. We provide excellent and reliable customer support from knowledgeable technicians ready to serve you and answer all your questions. You will always be talking to someone who completely understands our product line.
Contact CNC Masters today and watch your profits soar!