Below is a comprehensive buyer’s due-diligence checklist tailored for evaluating a used / surplus TOS SUS63×3500 universal (or “support / engine”) lathe (Czechoslovakia / Czech origin, by TOS). Use this to verify condition, spot red flags, estimate refurbishment cost, and negotiate with confidence.

some reference data for the SUS63×3500 to anchor expectations:

• Swing over crosslide: ~ 390 mm
• Center (turning) distance: 3,500 mm
• Spindle speed range: approx. 7 – 1,120 rpm
• Motor: ~25 kW drive
• Weight / dimensions: length ~ 6,400 mm, width ~1,750 mm, height ~1,500 mm, weight ~7,100 kg

Those are reference values; the actual machine you inspect may differ (e.g. modifications, wear, retrofits). Use the checklist below and record actual measurements.

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Inspection & Testing Checklist for TOS SUS63×3500 Universal Lathe

Area	What to Inspect / Test	Why It Matters & Risk	Suggested Checks / Targets / Notes
1. Identity, Nameplates, and Spec Confirmation	• Check nameplates, builder plates, serial numbers, and stamped data (swing, bed length, maker, year). • Confirm that the model is indeed SUS63×3500 or variant. • Verify any control retrofits, modifications, or non-original parts.	Ensures you know exactly what you’re buying, helps in sourcing spares and comparing to expected spec.	The machine should match a “63 / 3500” designation (i.e. ≤ 630 mm over bed, 3,500 mm swing).
2. Frame, Bed, & Base Structure	• Inspect the bed, bedways, guides, gap in gap-bed (if gap version) for wear, corrosion, chatter marks. • Look for cracks, repairs, welds, distortions in the bed, base, mounting brackets. • Check alignment/twist in the base. • Assess lubrication channels, drains, cast iron integrity.	The structural foundation dictates accuracy, rigidity, and lifetime. Repairing a warped bed is very expensive.	The bed should be straight, flat within tolerance for your workbearing requirements. No obvious repairs or misalignment.
3. Headstock & Spindle	• Rotate the spindle manually (if safe) and feel for smoothness, binding, or rough spots. • Run test spindle at low speed; listen for abnormal noise, hum, vibration. • Measure spindle runout (with a precision bar or dial indicator) at the nose and outboard • Check bearing condition (temperature, play) • Inspect spindle nose and taper for wear, nicks, and cleanliness • Inspect internal gear / drive train (if geared) for backlash, wear	The spindle is among the most expensive and critical components; bearing failure, wear, or damage severely degrade performance.	Acceptable runout should be within few microns (≤ 0.01 mm or better, depending on your tolerances). No excessive play in bearings.
4. Gears, Feed Drives & Transmission	• If the machine uses gears or gearboxes for spindle speed changes or feed changes, shift through all speeds and observe behavior. • Listen for gear whine, clashing, backlash, lugging. • Check condition of gear teeth (pitting, wear), lubrication of gearboxes. • Test longitudinal and cross slide drive mechanisms (leadscrews, nuts, gear trains). • Check for backlash in feed screws and nut wear.	Worn gears or drive trains can result in inaccuracy, vibration, inability to maintain consistent speeds/feeds. Gearbox repair is costly.	Smooth transitions, minimal backlash, no abnormal noise, no binding.
5. Cross Slide / Carriage / Tool Slide Condition	• Check travel in longitudinal (Z) and cross (X) axes; observe for binding, roughness, or hesitation. • Use dial indicators / test bars to measure straightness and flatness across travel. • Check surface finish of guide ways, condition of way wipers, lubrication components, wear marks. • Measure backlash or play in the slides, nuts, or gibs. • Verify “rapid traverse” if present.	Poor slide condition leads to inaccuracy, chatter, inability to maintain tolerances.	Slide motion should be smooth, no stiction, minimal backlash (within your tolerance). Wipers and lubrication should be intact.
6. Tailstock & Alignment	• Check the tailstock spindle / quill: smooth travel, no binding, minimal play. • Inspect quill taper, diameter, condition. • Verify alignment of tailstock along the bed: test by setting indicator on a known bar and moving carriage. • Check tailstock locking mechanisms and clamping.	Tailstock misalignment or worn quill can cause taper, runout, or poor support of longer workpieces.	Tailstock offset should be minimal relative to your part tolerances (often ≤ a few hundredths of a mm over full length).
7. Chuck, Jaws, Clamping & Workholding	• Inspect chucks (3-jaw, 4-jaw) and their jaws for wear, damage, proper grip. • Check mounting, keyway, fastening surfaces. • If the machine has special workholding (steady rests, follow rests), inspect their condition and alignment. • Test clamping / unclamping operations.	Poor workholding degrades accuracy, causes slippage, or damage to workpieces.	Chucks should grip firmly and uniformly. Jaws should be true, not overly worn or damaged.
8. Controls, Electrical Systems & Wiring	• Open control panels and inspect wiring, connectors, terminal blocks, relays, fuses, circuit breakers for signs of overheating, corrosion, melted insulation, or repairs. • Test all switches, buttons, emergency stops, indicator lights. • Confirm power compatibility (voltage, phase, current) with your facility. • If there is a digital readout (DRO) or CNC control retrofit, verify its functionality, accuracy, and interface (inputs/outputs, memory, backup). • Look for custom wiring or modifications that deviate from standard configuration.	Electrical faults often cause machine downtime or catastrophic failures. Having a clean, reliable wiring/control system is essential.	All electrical panels must be clean, well-maintained. No burnt components, wires, or loose connections. Controls should function as intended.
9. Lubrication, Coolant & Auxiliary Systems	• Check the lubrication system: oil pump, lines, filters, reservoirs, flow to ways and slides. • Inspect coolant systems (pump, plumbing, nozzles, filters) if the lathe is equipped. • Look for leaks (oil, coolant) or past repairs in plumbing. • Inspect chip guard, chip removal system (splash guards, scrapers, coolant return paths) • Check seals, gaskets, wipers, and that the machine is sealed to prevent ingress of chips or coolant into sensitive parts.	Good lubrication and coolant are necessary to maintain tolerances and reduce wear. Poor auxiliary systems accelerate degradation.	Lubrication lines should deliver oil, lines should be clean. No significant leaks. Coolant flow should be adequate and controllable.
10. Safety, Guards & Interlocks	• Ensure all guards, splash shields, covers, and protective enclosures are present and in place. • Test emergency stops, limit switches, door or access interlocks. • Check the robustness of guard design (i.e. they should withstand impact or deflection). • Confirm proper grounding of electrical components. • Verify any signage, safety labels, and that operator control zones are safe.	Safety compliance is essential for legal use, operator protection, and liability. Missing or bypassed interlocks are serious red flags.	All safety devices should be functional. No bypassed switches or open panels while running.
11. Test Runs & Performance Evaluation	• Run the lathe (if power available) with no load first — jog motions, axis moves, spindle run. • Then perform test cuts (turning, facing) on a suitable workpiece (steel or your typical material). Examine finish, geometric errors, drift. • Run extended (soak) test to detect heat drift, vibration changes, shifts, or emergent faults. • Cycle through full speed, feed ranges, direction changes, axis reversals, and long travel moves. • Monitor temperature of bearings, motors, gearbox, and observe vibration or noise changes over time. • If possible, perform an alignment / calibration test (e.g. check taper, cylindricity, straightness over the full length).	This is your “proof in action” — many defects reveal themselves only under actual operation or time.	The machine should operate smoothly, maintain consistent finish, not overheat, and not produce faults or drift beyond acceptable tolerances.
12. Measurement & Benchmark Data Collection	• Using indicators, sensors, or measurement tools, record: spindle runout, vibration amplitude, backlash in slides, positional deviation over travel, thermal drift over time. • Compare your measured data with your required tolerances (for your parts) and with reference spec (if known). • Take photos of wear areas, measurements, alignment test data.	Data is your evidence for negotiating, acceptance, or rejecting the machine. It helps quantify the condition.	The measured values should fall within your tolerance envelope for production. If they are outside, you must assess repair cost.
13. Maintenance History, Documentation & Spares	• Request any maintenance logs, repair records, overhaul history, parts replacement logs. • Ask if any major repairs or accidents (crashes) occurred. • Confirm presence of original or as-built documentation: wiring diagrams, parts list, mechanical drawings, service manuals. • Check availability of spare parts (bearings, slides, gears, chucks, ways, etc.) for this model. • Ask about whether TOS or aftermarket support is available in your region.	Even a good machine can become unusable if you can’t source parts or knowledge. Documentation increases your ability to service it.	Comprehensive documentation and spares availability.
14. Transport, Installation & Site Requirements	• Determine the machine’s weight, footprint, and center of gravity to plan rigging and floor support. • Check that your facility’s floor can support ~7,000 kg (or actual weight of this unit). • Plan for costs of disassembly, rigging, re-leveling, alignment, and recommissioning. • Confirm access paths (doors, cranes, lifts) to move the machine into place. • Check power supply (voltage, phase, capacity), grounding, compressed air (if used), coolant supply, drainage, and ventilation.	Hidden costs in moving, installing, and aligning can be significant. Poor site preparation can compromise machine performance.	Ensure your shop infrastructure is adequate. Rigging plan should be safe and feasible.
15. Warranty / Acceptance Terms & Risk Mitigation	• Try to negotiate a short test / acceptance period (e.g. 30-90 days) during which you can run and validate performance. • Tie final payment to successful performance against key criteria (accuracy, finish, reliability) • Insist that the seller disclose known defects, and possibly provide a limited warranty on critical subsystems (spindle, gears) • Ask for spare parts (if available) to be included or priced separately • Document condition with photos, test results, before final acceptance	Because used machines carry risk, you need contractual safeguards and leverage to protect yourself.	A successful acceptance clause helps reduce your exposure to hidden defects discovered later.
16. Pricing Adjustment & Repair Reserve	• After inspection and measurement, estimate the cost of repairs, replacements (bearings, slide repair, alignment, retrofits) • Leave a margin in your offer to absorb surprises • Use defects or measurement deviations as leverage to lower price or request seller to address issues • Don’t pay as if the machine is “good as new” — incorporate refurbishment cost into your bid	Even well-maintained machines often require “tune-up” work before reliable production. You should not be caught paying for unknown costs.	A prudent reserve (often 10–25 % of purchase price) should be assumed for commissioning / repairs.