Here’s a detailed, professional-grade “pre-purchase audit” guide for a used / surplus / secondhand Hitachi Seiki HT25 (or HT-25 / HT25S / HT25R variant) CNC lathe, focused on helping you avoid costly mistakes. Use this as your walk-around & test checklist. (You can adapt it for your shop’s tolerances / job mix.)

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0. Know the baseline spec & variants (what “HT25” typically is)

Before visiting, get familiar with what a “normal” HT25 should deliver — so you can spot deviations or red flags.

From public listings:

• The HT-25-S variant is listed with swing 508 mm (20 in) and turning length ~609.6 mm (24 in)
• Power: ~18.6 kW spindle motor.
• Chuck / bar capacity: 254 mm (10 in) chuck; bar capacity ~63.5 mm
• Some HT25R models: turning length 600 mm, turning Ø ~2550 mm (likely a misprint or unit mix)
• One listing: HT25 with Fanuc System 10T, 12-position tool changer, tailstock, chip pan
• Some HT25S listings: chuck 200 mm, turning Ø 380 mm, turning length 630 mm, X travel ~240 mm, Z ~650 mm, 11 kW spindle, 12-position turret

These give you ballpark ranges for capacity, power, and features. If a machine diverges heavily (e.g. tiny spindle motor, much more worn, missing turret, bad electronics), those differences must be explained.

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1. Pre-inspection homework / document request

Before visiting the machine in person, ask the seller for:

• Maintenance logs, repair history, parts replaced
• Machine usage / runtime / cutting hours
• Original manuals, electrical / mechanical schematics
• Control software versions, backups, parameter files
• List of modifications, retrofits, or parts swapped
• Reason for sale
• Photos and video (especially running, parts, close-up of critical components)

If the seller can’t provide credible documentation, consider that a major risk factor.

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2. Visual & structural inspection

Walk the perimeter and scrutinize the machine’s shell, frame, and visible components. Use a flashlight, close-up photos, and measuring tools.

What to look for:

• Frame, bed, base — any cracks, weld repairs, distortion, sagging
• Bed ways / guides for wear, pitting, scoring
• Turret housing, spindle headstock, tailstock, cross slides — look for damage, misalignment
• Guards, covers, safety shields — missing or damaged ones are red flags
• Signs of rust, corrosion, water ingress (especially in coolant tray, under base)
• Overall symmetry and alignment — e.g. both sides of turret, machine frame must mirror each other

If you see structural repairs (welds, straightening, cracks) in the frame or bed, that’s high risk.

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3. Spindle & headstock inspection

The spindle is the “heart” of a lathe — problems here are often expensive.

• Rotate the spindle (if manual rotation is possible) — listen and feel for rough bearing noise, binding, stiffness
• Check for radial and axial play / runout using a dial indicator (front nose, internal bore)
• Inspect the spindle bore (through-hole) for wear, pitting, ovality
• Check the spindle bearings’ condition (signs of oil leakage, discoloration, heat damage)
• Review headstock lubrication, gear box (if any), spindle drive mechanism
• Check spindle nose taper (A2-8, etc.) and ensure integrity of mounting
• Note any overheating evidence, discoloration, or modifications

If the spindle has excessive play or noise, that’s a major red flag.

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4. Axis motion, slideways, precision & backlash

Check how the axes (typically X and Z) move, their precision, and mechanical wear.

• Move the X and Z axes (manual JOG or handwheel) — watch for binding, roughness, or jumps
• Feel for backlash or “dead zones” in each axis
• Check the condition of the guide ways / slideways / gibs — look for scoring, uneven wear, lack of lubrication
• Inspect screw / ball screws, nuts, bearings, couplings for play or wear
• Check alignment: the tailstock and spindle should remain coaxial; cross slide should move true
• Ensure lubrication points are present and functional

If the axes are sloppy, uneven, or have bad backlash, achieving tight tolerances may be impossible.

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5. Turret / tool changer / tooling system

Many problems in used CNC lathes center in the turret / tool changer area. Inspect carefully.

• Check that the turret indexes cleanly, clamps firmly, with no chatter or misalignment
• Watch for turret “seek errors,” mis-index alarms, or reluctance to shift
• Inspect tool holders for wear, play, or damage
• Check the clamp / unclamp mechanism, servo or hydraulic actuation, sensors or switches
• Confirm turret drive (belt, gear, motor) is properly aligned and no unusual noise
• Verify whether the turret can be manually indexed (test JOG)
• Ensure the turret indexing matches tool program calls (i.e., tool #5 is actually in position 5)

Many HT25 owners report turret / tool indexing quirks, or need to reset turret position after interruptions.

If the turret is misbehaving or intermittent, that can severely limit productivity or require major repair.

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6. Control system, electronics & software

Because this is a CNC machine, the control & electronics are as critical as mechanical parts.

• Power on the machine — monitor the boot sequence, alarms, error logs
• Check the control panel, screen, buttons, switches, emergency stop, indicators
• Inspect wiring, junction boxes, connectors for signs of overheating, corrosion, splices, aftermarket modifications
• Test limit switches, home/reference switches, sensors, interlocks
• Check the CNC control (e.g. Fanuc, SEICOS, etc.) and see whether software / parameters are intact
• Load parts / programs (if possible) and verify axes move as commanded
• Check whether backups or archived projects exist
• Examine I/O modules, drives, power supplies, whether the electronics appear original or replaced
• Verify communication ports (USB, serial, Ethernet) if relevant

If the controller is missing, corrupted, or partially inoperative, repair or replacement may be very expensive.

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7. Functional test & trial machining

Words and photos are good, but you must see the machine operate under realistic load conditions.

• First, run in idle / no-load mode to detect any abnormal motion, drift, vibrations, or leaks
• Execute a test cut using material and dimensions similar to what you’ll actually run
  • Across various radii, axial lengths, diameters
  • Inspect part dimensions, tolerances, surface finish, concentricity, taper
  • Repeat multiple parts to check consistency / repeatability
• Test axis repeatability: command the same position several times, check variation
• Cycle tool changes repeatedly: check speed, mis-indexing, chatter, errors
• Test tailstock (if present): move, clamp, retract, check alignment with spindle axis
• Run error/recovery tests: abort mid-cycle, emergency stop, see how the machine recovers
• Run with coolant / chip handling: check coolant flow, leaks, chip path, cleanliness

If the machine cannot deliver consistent parts within your required tolerances during the test, its usefulness is severely limited.

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8. Precision, calibration & measurement verification

Bring measuring instruments (micrometers, dial indicators, gauge blocks) and perform:

• Spindle runout (internal and external)
• Check linear axis accuracy across travel
• Measure backlash in axes
• Inspect surface finish and compare with expected quality
• Check tool offsets, tool repeatability
• Inspect concentricity / taper / perpendicularity
• Compare measured values vs prior calibration or factory specs (if available)

If errors are large and beyond what your parts demand, correcting them may require rebuilding or realignment, which can be costly.

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9. Spare parts, support & lifecycle risk

A used machine is only as good as your ability to maintain and repair it going forward.

• Verify availability of spare parts (bearings, pressed-in parts, tool holders, turret parts, electronics) for HT25 lathes
• Ask whether there’s aftermarket support or local service houses familiar with Hitachi Seiki machines
• Determine whether control electronics or modules are still obtainable
• Ask if the seller includes parts, tooling, or spare modules
• Consider the cost and lead time of likely future repairs or wear-parts

If spare parts are obsolete or scarce, you may find yourself unable to keep the machine running in reasonable cost.

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10. Pricing & negotiation using observed defects

By this point, you should have an itemized list of “deficiencies” or concerns. Use that in negotiating:

• Get cost estimates to fix / recondition major issues (spindle, turret, electronics)
• Ask the seller for price deductions for each defect or an allowance for a rebuild
• Include rigging, transport, installation, leveling, commissioning costs in your bid
• Build a contingency buffer (10–20 %+ of your bid) for unforeseen problems
• If possible, obtain a short warranty or conditional “acceptance period” for performance

Don’t let emotional attachment push you to overpay for uncertainties.

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11. Post-purchase installation & commissioning checklist

Once you acquire the machine, do the following carefully:

• Ensure a stable, level foundation and proper anchoring
• Check and stabilize power supply, grounding
• Flush coolant / lubrication / hydraulic systems, replace filters
• Verify alignment, calibration, tool offsets, and mechanical synchronization
• Run break-in sequences: start light, gradually increase loads
• Re-check tolerances and performance under load
• Train operators & establish maintenance protocols and logbooks

Any early drift or instability should be documented immediately — in some cases, you may have recourse if the purchase agreement allows.

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12. Red flags / deal-breakers to watch for

Here are issues that may push you to walk away (or demand steep discount):

• Excessive spindle play, noise, or bearing problems
• Turret indexing failures, mis-index, or consistent turret errors
• Control system missing, corrupted, or obsolete beyond repair
• Severe wear / damage to ways, slides, guide rails
• Major structural repairs, weld damage to frame
• Missing, nonfunctional safety interlocks or guards
• Irreparable electronics or modules (PLC, I/O, drive cards)
• Absence of tooling, chucks, or support equipment
• Seller unwilling to permit full test cuts / functional trial
• Spare parts availability is nil or prohibitively expensive

If you encounter one or more of these in combination, proceed only with extreme caution.