Type the words ‘milling machines for sale’ into your favorite search engine. The results probably surprise you. Manual knee mills. Universal milling machines. Combination horizontal and vertical mills. Horizontal boring mills. In addition, those aiming for higher quantities or more complex workpieces have CNC knee mills and bed mills to consider.

Many makes and models exist, each with different capabilities. And yet, selecting the wrong one can be an expensive mistake. Given the stakes, it only makes sense to arm yourself with all of the information needed to make the right decision. Here’s a quick primer on the different options to get you started.

Milling Machines for Sale

The milling machines for sale journey begins with manual knee mills. A common sight in machine stops, machinists often refer to them simply as Bridgeports. That said, the original patent expired decades ago and the company that invented them has long-since changed hands (several times, actually).

Regardless, knee mills feature a movable ram and swivel head, on which sits a , vertically-oriented spindle with quill. This makes them very versatile. And as any skilled machinist will tell you, there’s little they can’t make on one. Because of this, they are often the first choice for prototyping and low-volume milling work.

Universal Capabilities

Universal milling machines have a fixed horizontal spindle supported by an adjustable outrigger. Some models, such as Kent USA’s KUM-series, boast a secondary vertical milling head for increased flexibility. Generally speaking, universal mills can carry heavier loads and take more aggressive cuts. However, they are every bit as accurate (maybe more so) than their close cousin the knee mill.

A Toolmaker’s Dream

Horizontal boring mills feature a heavy-duty quill and bed-style table. As such, they offer superior accuracy and metal-removal capabilities compared to their more general-purpose counterparts. For example, Kent’s KBM-8520 has a 50-taper spindle, 55″ x 32″ table, and precision-ground Acme screws in all three axes. This makes them a favorite among tool and die makers and shops that need to machine larger parts and maintain very close tolerances.

Straddling the Fence

CNC knee mills and bed mills straddle the fence between manual and full CNC machines. Machinists can operate these versatile machines as they would any of the mills just listed—by cranking the handles. But for higher part volumes or complex features, these versatile machine tools can also go “full auto.” And because they have a conversational control (the KTM-3VKF from Kent uses a MillPwr G2 from ACU-RITE), even a beginner can program one. Because of this, they are the perfect stepping stone for the shop that can’t yet justify a CNC machining center.

Now What?

These brief descriptions are a good start. You’re not quite done checking all the milling machines for sale checkboxes, though. For instance, consider machine construction. Look for a heavy machine made of Meehanite cast iron with hardened and ground ways. ABEC-7 class spindle bearings are similarly important. An AC-frequency drive head provides infinitely variable spindle speeds (no more pulley changing), not to mention years of dependable service.

Once you’ve decided on the type of milling machine, take a hard look at the company standing behind it. What about their service? Is the sales and applications staff knowledgeable? Will they support their product after the sale? What do their other customers have to say about their machinery? Are parts readily available? If you want to get the best bang for the machining buck, be sure to answer these questions. And if you need a little advice, give us a call. We’ll help steer you towards the right machine, even if it ends up being from a competitor. That’s how we roll.