24/09/2025 By CNCBUL UK EDITOR Off

Avoid Costly Mistakes: Professional Tips for Purchasing a Pre-Owned / Second-Hand / used Nakamura-Tome SC-150M CNC Turning Center?

When you’re considering purchasing a used Nakamura-Tome SC-150M (or similar Nakamura turning center), you’re dealing with a precision machine that demands rigorous vetting. Below are professional tips—drawn from best practices in machine tool procurement—that help minimize risks and avoid expensive surprises.

1. Understand the Machine & Its Baseline Spec

Before visiting the seller, try to gather the as-built specification of the SC-150M (or closest model). You want to know what “normal” performance looks like (travels, spindle, tooling, control). This gives you a benchmark to identify exaggerations or hidden defects.

Key spec areas to research:

Axis travels (X, Z, possibly Y or sub axes, if applicable)
Spindle specifications: speed range, torque, power, taper, bore
Turret / tool changer: number of stations, indexing type, driven tools / live tooling
Rapid / feed rates
Control type and version (Fanuc, Mitsubishi, OEM)
Structural design: slide way types (box ways, linear ways, dovetails), rigidity, machine weight
Auxiliary systems: coolant, chip removal, guarding, bar feed or sub spindle (if equipped)
Typical tolerances for repeatability, axis accuracy, roundness, etc.

Knowing those specs gives you a “truth table” against which to check what the seller claims.

2. Documentation & Machine History

One of the biggest sources of risk is unknown wear, modifications, or neglect. Good documentation can dramatically reduce that risk.

Request from seller:

Service / maintenance logs: history of lubrication, drive replacement, spindle servicing, etc.
Repair invoices, parts replaced (especially major items like spindle, bearings, drives)
Controller backups / programs / parameters: configuration files, tool offsets, macro programs
Original manuals, wiring diagrams, schematic drawings
Modification records: any retrofits, non-OEM parts, alterations to structure or electronics
Hours / cycles logged (if available)
Usage type & environment: Was the machine used in high-volume production, light duty, or harsh environments?
Spare parts inventory: what comes with the sale (collets, turret inserts, spare cables, sensors, etc.)

If the seller cannot provide credible history, that should lower your confidence or your offer.

3. Visual & Structural Inspection

Even before powering it up, inspect the machine’s physical condition closely.

Check castings (bed, base, headstock shell, turret housing) for cracks, weld repairs, distortions
Inspect for corrosion, pitting, surface rust on slideways, ways, tool holders, turret faces
Look at way covers, bellows, guards — damaged or missing covers often indicate internal abuse
Ensure all guards, panels, fasteners are present and undamaged
Look carefully for oil / coolant leaks, stains, or seepage around seals, pumps, spindle heads
Examine installed tooling, fixtures, chucks: wear, damage, misfitting parts can hint at rough usage

Structural issues are often expensive or impossible to fully remedy, so be cautious if you spot them.

4. Mechanical & Motion Inspection

This is where the real evaluation begins—testing axes, backlash, smoothness, noises, etc.

Axes & Slideways

Jog each axis across full travel (X, Z, optionally Y) at low and medium speeds. Feel for irregular motion, stiffness, rough spots, or binding.
Use a dial indicator to measure backlash (reverse direction play). Excessive backlash is a sign of worn nuts, screws, or mechanical slack.
Watch for “soft spots” or zones where the motion feels not uniform — this can point to worn ways or underlying alignment issues.
Listen for squeaks, grinding, or rubbing sounds while moving axes.
Inspect ball screws / lead screws and nuts for wear, pitting, or longitudinal play.
Check that lubrication systems to slides / screws are intact (oil lines, pumps, distribution) and functioning.

Spindle & Toolholding

Run the spindle at multiple speeds (low, mid, high) with no load. Listen for humming, bearing noise, vibration or unsteady behavior.
Use a test bar or mandrel: measure radial and axial runout (turn 360°) with a dial indicator.
Inspect the spindle taper / interface for damage, scoring, wear, or misalignment.
Check tool change cycles (if auto tool changer or turret): time, consistency, repeatability.
If there are live tooling / driven tools, test them (no load) and monitor for vibration, smooth operation, and any electrical anomalies.

Turret / Tool Changer

Cycle the turret through many index operations; watch for hesitation, misalignments, or indexing errors.
Verify tool pocket fit / clearance; check for looseness or side play.
If there is a servo or cam indexing system, listen for noise or signs of wear.
If driven tools are in pockets, test their rotation (no work load) for smoothness and runout.

5. Electrical, Control & Software Inspection

Even a perfectly mechanical machine is useless if the electronics or control are faulty.

Open the control / electronics cabinet: inspect for dust, burn marks, discoloration, corrosion, loose wires
Check for missing modules, drives, power supplies, communication cards, labels
Power up the control: check for error or fault history, alarm logs, boot issues
Test all switches, pushbuttons, emergency stop, panel indicators, displays, encoders
Cycle the machine (without cutting) under control, monitor for any overheating, faults, or anomalies
Verify control interface (parameter menus, memory backup, program load / save) is fully functional
If possible, get the CNC parameters / configuration files to inspect for tampering or customization

6. Geometric & Accuracy Tests

These are critical to assess whether the machine is still within usable precision tolerances.

Use a reference surface or granite plate and dial indicator to check flatness / straightness of slide movement
Measure squareness (e.g. X to Z, turret axis to spindle axis) with test indicators or precision gauges
Tram the spindle / head if adjustable, to ensure its axis is correctly aligned with the work axis
If feasible, run a “test cut”: a finish pass on a known material, then measure features (diameter, straightness, concentricity, surface finish) in multiple positions (beginning, mid, end of travel)
Compare before / after repositioning cuts (to gauge repeatability)
At extremes of travel and mid-range, test dimensional performance—discrepancies often get worse near travel limits

7. Hidden Costs & Risk Items to Assume

Even a machine that “looks good” may need investments. Identify and budget for them ahead of time.

Spindle rebuild or bearing replacement
Lead screw / nut replacement or refurbishment
Way reconditioning / scraping / alignment work
Control or drive electronics replacement / upgrade
Cable harness replacement or repairing aged insulation
Retrofits or modernization (if parts obsolete)
Calibration, alignment, certification
Transport, rigging, leveling, foundation work
Downtime during setup / tuning

Also consider the availability of spare parts. Some controllers or OEM parts may no longer be easily sourced.

8. Negotiation & Deal Structuring to Protect You

Always visit in person (if possible) with your inspection checklist and tools
Insist that the machine be run in your presence: full axis movement, spindle, turret, test cuts
Propose contingent payment: hold a portion until after successful acceptance test
Require that all documentation, electrical drawings, parameter backups, manuals be delivered with the machine
If feasible, negotiate a short-term warranty (30–90 days) on major systems (spindle, control, drives)
Ask that any known issues be disclosed in writing, so you’re not surprised later
If possible, get some training / setup / calibration assistance from the seller or third party