Cylindrical (OD) grinders
The workhorse of precision grinding. If your part has an outside diameter that matters — a shaft, a spindle, a pin, a roller — this is probably the machine.
What they're for
A cylindrical grinder rotates the workpiece between centers (or in a chuck) while a grinding wheel traverses along it, removing thousandths to bring the outside diameter to size and finish. It's the final sizing operation for an enormous range of parts: transmission shafts, motor spindles, hydraulic piston rods, bearing journals, cutting-tool shanks, rollers of every description.
Grinding earns its place where turning can't finish the job — hardened materials, tight diameter tolerances, fine surface finishes, and long slender parts that need steady-rest support to stay straight.
Plunge vs traverse vs angle-head
You'll see three configurations. Plunge (infeed) grinding feeds the wheel straight into the part — fast, ideal for single diameters and shoulders in production. Traverse grinding moves the wheel along the part's length — the choice for long shafts and tapers. Angle-head machines swivel the wheelhead (typically ±30°) so one setup can grind diameters, faces, and tapers. If your parts vary, angle-head flexibility is worth more than it costs.
Size ranges, in plain terms
CNC cylindrical grinders are generally described by two numbers: distance between centers (how long a part they take) and swing (how large a diameter clears). A representative mid-range class — for example Supertec's G series — spans roughly 20 to 80 inches between centers, with maximum grinding diameters in the 10 to 14 inch range. Small toolroom machines go shorter; large roll and turbine-shaft machines go much longer. Match the envelope to your longest and largest real parts, not your aspirations — oversized machines cost more to buy, power, and dress.
What to compare when you're shopping
- Work envelope vs your parts. Between-centers distance, swing over the table, and maximum grinding diameter. Bring your three most common parts, not your extremes.
- Wheelhead capability. Swivel range, spindle power, and whether the machine handles the wheel sizes your process needs.
- Control. Most Taiwanese-built grinders ship with Fanuc, which your people likely already know. See our controls comparison before worrying about this.
- Workholding. Centers, chuck, steady rests, and whether changeover between them is a ten-minute job or a half-day project.
- Dressing. How the wheel gets dressed (single-point, rotary diamond, crush) and whether it's programmable in-cycle. Dressing is where cycle time hides.
- Automation readiness. Even if you load by hand today, a machine that can take a loader later protects the investment.
- Service and parts in your region. A grinder is a ten-year relationship. Ask who answers the phone, where parts ship from, and what the typical response time is.
When cylindrical is the right call — and when it isn't
Right call: external diameters with tight tolerances, hardened materials, long shafts, parts where roundness and finish actually matter to function — bearing journals, seal diameters, spindle tapers.
Wrong call: high-volume small pins and bars with no critical shoulders — that's centerless territory, and it's dramatically faster. Very large heavy diameters — look at vertical grinders. Bores — that's internal grinding. If you only grind occasionally and your mix changes weekly, a universal grinder may serve you better than a dedicated OD machine.
What this class of machine costs
New Taiwanese-built CNC cylindrical grinders typically land in the roughly $120,000–$250,000 range installed in the US, depending on size and options (industry estimates — builders quote per configuration). Japanese machines generally run $200,000–$450,000; Swiss and German machines $400,000 to over $1,000,000. The value-tier pitch is straightforward: near-premium precision claims at roughly 40–60% below Swiss/German pricing. Whether that holds for your parts is what a test cut is for — always grind your own drawings before you buy.
The test-cut rule. Never buy a grinder on brochure specs. Any serious builder will grind your representative parts and send you the measurement data. If they won't, that's your answer about the builder.
Related
- Internal (ID) grinders — for the bores these parts often have
- Centerless grinders — for high-volume small-diameter work
- Grinding for automotive — shafts, gears, and drivetrain components
- New vs used — what a used premium machine costs against new value-tier