Meet the Machine

Toshiba TSS-30/55C

A 118″ table. A 216″ swing. Eighteen feet of CNC vertical boring and turning capability — and it’s available right now.

The Toshiba TSS-30/55C is a CNC vertical boring and turning machine. That description is accurate and doesn’t come close to capturing what the machine actually is. Its table diameter is 118 inches. Its maximum swing — the largest diameter a workpiece can reach while rotating on the table — is 216 inches. That is eighteen feet. The machine doesn’t process components the way most CNC equipment does. It processes the things that most shops don’t have the floor space, the crane capacity, or the equipment to take on.

Most machine tools are scaled to the work that comes through a typical shop door. The TSS-30/55C is scaled to a different category entirely — large-diameter rings and flanges, turbine casings, pressure vessel heads, and structural components whose weight is measured in tens of thousands of pounds. The 2013 Toshiba currently in stock at Resell CNC represents a rare opportunity to acquire a capability that rarely reaches the open market.

This is the first entry in Resell CNC’s Meet the Machine series: a closer look at the machines currently in inventory, what they were built to do, and what that means for the shops equipped to put them to work.

“A 216-inch swing means an eighteen-foot diameter workpiece rotating on a table capable of holding 44,000 pounds. There are very few machines in North America that can say that.”

What Is a CNC Vertical Boring and Turning Machine?

A vertical boring and turning machine — sometimes called a vertical turret lathe or VTL — is built around a horizontal rotary table rather than a horizontal spindle. Where a conventional lathe holds the workpiece in a chuck that spins on a horizontal axis, a vertical boring mill sets the part flat on a large rotating table and brings the cutting tools down from above.

The geometry change matters enormously for large, heavy parts. A workpiece weighing 20,000 pounds cannot be held in a conventional lathe chuck without extraordinary fixturing. Set flat on a horizontal table, that same part is stable under its own weight. Gravity becomes an asset rather than a challenge. The larger and heavier the part, the more the vertical orientation makes sense.

The ‘boring’ in the name reflects the machine’s primary historical capability — boring large-diameter holes, facing large surfaces, turning large outside diameters. The ‘turning’ reflects the rotary table motion that makes all of those operations possible. Modern CNC vertical boring machines like the TSS-30/55C layer milling capability onto that foundation, creating a platform that can complete a complex large-diameter component in a single setup.

Why Does 216 Inches of Swing Change the Conversation?

The swing of a vertical boring machine defines the largest diameter circle that can be rotated and machined on the table. A 216-inch swing means an 18-foot diameter workpiece can be turned, faced, and bored without moving the part. That number places the TSS-30/55C in a category of machine that most job shops never encounter and that most manufacturers never get to run without sending work outside.

For context: the table itself is 118 inches — nearly ten feet — in diameter. The maximum swing exceeds the table diameter because the machine’s column and guideway structure is engineered to allow overhanging workpieces to rotate past the machine frame. That design allows the TSS-30/55C to handle parts significantly larger than the table itself.

The table load capacity of 44,000 pounds is the other number that reframes the conversation. Forty-four thousand pounds is more than 20 tons. Components at that weight — large ring forgings, turbine casings, compressor housings, heavy excavator components — require this class of machine. They cannot be run on smaller equipment, and they cannot be fixtured on a conventional machining center. The TSS-30/55C is one of the few options that can take that work.

The cutting height adds a third dimension to the scale: 102.3 inches of vertical working envelope — nearly eight and a half feet from table surface to maximum tool reach. Combined with the swing, the machine can process components of exceptional diameter and height in a single setup, without repositioning.

“Most CNC machines are scaled to work that fits through a typical shop door. The Toshiba TSS-30/55C is scaled to a different category entirely.”

What Work Is the TSS-30/55C Built For?

The applications for a machine in this capacity class are defined by its numbers. A 216-inch swing and 44,000-pound table load point directly to industries where large-diameter components are the production standard, not the exception.

Energy sector manufacturers are the core customer for this class of machine. Turbine casings for power generation — gas, steam, hydro — are large-diameter castings and forgings that require precision boring, turning, and facing. Wind energy tower flanges and hub housings run large diameters and require the kind of table torque the TSS-30/55C delivers: 31,120 lbf.ft is not a number that comes from a small machine. Upstream oil and gas work — wellhead components, blowout preventer bodies, large valve housings — lands in the same capacity class.

Mining and heavy equipment manufacturers need this scale for sheave wheels, large bushings, trunnions, and mill components. Pressure vessel fabricators need it for head turning and flange facing. Defense contractors working on large structural components and aerospace suppliers manufacturing large rings and bulkheads need the combination of size, precision, and control capability that a modern CNC vertical boring mill provides. The common thread is parts that are too large for conventional turning, too heavy for horizontal machining, and too complex to complete without milling capability in the setup.

The One-Setup Advantage

Every time a large, heavy workpiece is moved between machines, the same sequence plays out: the part is lifted, repositioned, and re-indicated. Each transfer takes time — sometimes hours on a component this size — and introduces setup error that accumulates against the finished part’s tolerances. For a component requiring turned diameters, faced surfaces, drilled bolt patterns, and bored cross-features, the traditional answer was multiple machines, multiple setups, and multiple opportunities for error.

The TSS-30/55C’s 24-position automatic tool changer — carrying 8 turning tools and 16 milling tools — changes that calculation. Rough turn the outside diameter, face the surfaces, mill the bolt circle, bore the cross-holes, and probe the finished features — all without moving the part. On a component that takes four hours to set up each time it moves, the economics of single-setup machining are immediate.

What Makes This More Than a Standard Vertical Turning Lathe?

A basic vertical turning lathe turns and bores. The TSS-30/55C does those things and adds a live spindle capable of 1,500 RPM through a 50-taper interface — the same heavy-duty taper standard found on large machining centers. The 16-position milling magazine handles tools up to 15.7 inches wide and 19.6 inches long, with individual tool weights up to 110 pounds and a total magazine capacity of 1,100 pounds. This is not a token milling attachment. It is full milling capability integrated into a vertical turning platform.

The Fanuc 31iA control provides the axis management to make that integration work. X, Z, and C axes are CNC-controlled simultaneously. The C-axis — the table rotation — is not just for positioning. At a feedrate range of 1 to 315 degrees per minute, the table participates in the cutting motion. Combine C-axis contouring with helical interpolation and the machine can produce helical features — threads, spirals, angular lead geometry — on large-diameter components that no other single machine in this capacity class can complete without moving the part.

High-speed skip and tool retract-and-recover are the less-discussed features that matter in production. High-speed skip allows the control to detect and respond to tool contact events faster than conventional feed-hold — important for in-process gauging on a machine where resetting a single tool can cost an hour. Tool retract-and-recover means a power interruption during a cut doesn’t necessarily ruin the part; the control remembers where it was and can return to the cut path.

What Do the Specs Actually Tell You?

The ram section of 9.84 inches by 9.84 inches — 250mm square — housed in four closed guideways tells you something specific about how the TSS-30/55C handles interrupted cuts. A ram with that cross-section, guided on four faces rather than two, resists the deflection that heavy interrupted cuts produce. Large castings have sand inclusions, weld repairs, and surface irregularities. A rigid ram structure keeps the tool on path through those interruptions. Vertical boring of large castings is not smooth, continuous cutting. The machine has to absorb what the part throws at it.

The Heidenhain optical rotary pulse scale on the C-axis and Heidenhain linear scales on X and Z are the precision foundation the machine builds its accuracy on. Heidenhain scales are the position feedback standard on precision machine tools — their optical reading technology eliminates the backlash and wear error that accumulates in systems relying on motor encoders alone. On a machine handling parts this large, where finished tolerances on a turbine casing bore or a pressure vessel flange face are measured in thousandths of an inch, the quality of position feedback is not a secondary concern.

The Renishaw RMP60 radio machine probe adds in-process measurement — the ability to check feature dimensions while the part is still on the table, before unloading. On a component that took a crane and two hours to set up, verifying and correcting before releasing the part is worth more than the probe costs.

“The Heidenhain scales, the Renishaw probe, the closed-guideway ram — none of these are luxury features on a machine this size. They’re the minimum equipment required to hold tolerances on parts this large.”

Who Is This Machine For?

The TSS-30/55C is not a general-purpose machine. It is a specialist — built for a specific class of work and exceptional at it. The shops that need it know exactly what they need: contracts for large-diameter components, crane capacity to handle 44,000-pound workpieces, and the floor space and power infrastructure to run a machine this size. If that describes your shop, this machine is worth a serious look.

What the Toshiba offers that newer machines in this class rarely match is the combination of proven reliability, full turn-mill capability, and a modern Fanuc 31iA control on a 2013 platform. The 31iA is not a legacy control. It communicates with current CAM software, supports high-speed machining functions, and runs the same G-code programs that run on any current Fanuc-equipped equipment. A shop already running Fanuc has a control its programmers and operators already know.

Machines in this capacity range rarely come to market. When a shop running this class of equipment decides to upgrade or consolidate, the machine typically moves slowly. The 2013 TSS-30/55C currently available through Resell CNC is the kind of acquisition that the right shop should evaluate before someone else does.

“Machines in this capacity range rarely come to market. When one does, the shops that need this class of equipment know it immediately.”

Want to See It Running?

Resell CNC’s YouTube channel features walkaround and in-depth machine videos for equipment currently in inventory. If you want a closer look at the TSS-30/55C before making a call, head over to the channel for a visual walkthrough of the machine on the floor.

Watch the Toshiba TSS-30/55C walkthrough on the Resell CNC YouTube channel: youtu.be/NpzGC4Smh28