Here’s a detailed, structured guide and checklist for evaluating a pre-owned / surplus Universal Cylindrical Grinder like the TOS Hostivař BUA 25/1000 (or similar BUA / BUB class machines) before purchase. I’ll also highlight known specs of the BUA 25/1000 as a working reference point.

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1. Understand the model & nominal specifications

Before you even visit the machine, gather as much documentation and specs as possible. For the TOS Hostivař BUA 25/1000, here are some reference data:

• It is a universal cylindrical grinding machine (can do external, internal, plunge, maybe taper grinding).
• Weight: ~ 3000 kg (depending on configuration)
• Power input: ~ 4 kW (for the “CNC changed / overhauled” version)
• Swing (max diameter): ~ 279–280 mm (i.e. the largest external diameter it can grind)
• Distance between centers: about 990.6–1000 mm (i.e. 1 m length capacity)
• The model is listed as “discontinued” in many catalogs, so spare parts / documentation availability is something to be wary of.
• Some versions are manual, others possibly retrofitted with CNC capability. The listing at Limetech calls a “BUA 25/1000 CNC” with total input 4 kW.

Knowing the “as-new” specification gives you a benchmark to measure deviations, and helps you verify whether the machine you’re inspecting matches those capabilities or has been modified/ upgraded.

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2. Pre-visit preparation: questions & documentation to request

To avoid surprises, ask the seller (or the person in control) to provide:

1. Service, maintenance & repair history
   • Spare parts replaced (especially spindles, bearings, guideways, ballscrews, drives)
   • Any major rebuilds or retrofits
   • Dates of last calibration, alignment, regrind, or overhaul
2. Drawings, OEM manuals, wiring / electrical schematics
   • As-built drawings, control wiring, hydraulic / pneumatic schematics
   • Parts lists (especially for critical spares)
3. Operational logs / power-on hours / actual working hours
   • How many total hours, how many in part loading / idle / running
   • Warm-up cycles, spindle run time
4. Spare parts & tooling inventory
   • Whether wheels, dressers, coolant pumps, chucks, internal grinding attachments, balancing equipment come with it
5. Control / electronics details
   • What control system is installed (analog, CNC, brand, version)
   • Date of last firmware / software update
   • Whether control is fully functional
6. Photos / video of the machine in operation
   • In motion (axes moving), spindle running, part grinding
7. Environmental / site log
   • Operating environment (humidity, dust, coolant contamination)
   • Was the machine idle for long stretches?
8. Transportation & rigging plan
   • How they plan to disassemble it for transport
   • Whether alignment and reinstallation will be included

Having this information beforehand can save time and help you target what to inspect.

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3. On-site inspection checklist

Once you reach the machine, do a systematic inspection. I break this into mechanical, electrical / control, functional / test, and ancillary systems.

A. Mechanical inspection

Component	What to Check	Acceptable / Warning Signs
Bed, base, casting	Check for cracks, welds, distortions, corrosion. Ensure the machine is rigid and hasn’t been “patched up.”	Minor surface corrosion is OK; structural cracks or large repairs are a red flag.
Guideways / ways	Inspect for scratches, wear marks, scoring, pitting. Measure flatness or runout if possible.	Smooth movement without binding; excessive wear, unevenness, or need for re-scraping is concern.
Ballscrews / feed screws / leadscrews	Check backlash, wear, remove covers to inspect threads.	Minimal backlash, smooth travel; excessive back-lash or groove wear signals possible replacement cost.
Spindle & bearings	Run the spindle (if possible) at various RPMs, listen for noise, feel for vibration or heat, check for radial/axial play.	Quiet, stable running; no excessive vibration, no audible knocking. Bearing failure is costly.
Chucks, work-holding, tailstock, centers	Check alignment, wear, taper condition.	Worn tapers, damaged grips, misalignment are red flags.
Grinding wheel spindle and wheel arbors	Check the wheel mounting, runout, balancing capability, spindle bearings.	Excessive runout, wobble, or inability to balance a wheel indicate need for spindle overhaul.
Dressing / dressing mechanism	Check if the dresser works, condition of diamond / dresser tools.	If dressing is dysfunctional or missing, that’s a required repair.
Coolant / fluid systems	Inspect coolant tank, pump, piping, filters, cleanliness, leaks, corrosion.	Clean system indicates good maintenance habits; sludge, rust, leaks are warning signs.
Hydraulics / lubrication systems	Check oil lines, pumps, leakage, pressure, automatic lubrication (if equipped).	Any leaks, weak pressure, or nonfunctional lubrication are red flags.
Covers, guards, enclosures	Check if protective covers, splash guards, guarding are intact.	Missing covers may suggest past damage or neglect.

After you inspect visually, if possible, bring measuring tools (dial indicators, straightedges, test bars) to measure critical tolerances (e.g. table flatness, spindle runout, parallelism).

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B. Electrical / Control / Electronics

• Control panel & interface: power it up, test buttons, switches, alarms, jog mode, etc. All user inputs should respond promptly and correctly
• Wiring and connectors: inspect for frayed wires, corrosion, loose connections, burnt insulation
• Drives / motors / amplifiers: check their condition, whether thermal protection works, cabling is intact
• Feedback systems / encoders / resolvers: verify signal integrity (jitter, lost counts)
• Grounding, shielding, noise suppression: good practice is essential in older machinery
• Safety circuits, interlocks, E-stop: test safety mechanisms, emergency stops, limits
• Backup battery, memory, parameter storage: make sure control settings are preserved

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C. Functional / operational tests

Assuming the machine is powered and (if allowed) you can run it:

• Move all axes (X, Z, etc.) through full travel, listen and feel for binding, stiction, jumps
• At low and higher feed rates, check smoothness of feed
• Run the spindle (if possible) at varied speeds, monitor vibration, noise, temperature
• Perform a test grind: mount a test bar or cylindrical sample, grind a known diameter, check dimensional accuracy, roundness, surface finish
• Check directional reversal backlash (go in one direction then reverse)
• Check spindle starting, stopping, reversing, braking behavior
• Perform a test with dressing (if internal/external)
• Verify that all gauges / readouts correspond to actual movement

If possible, have an experienced machinist or metrologist accompany you for these tests.

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D. Ancillary systems & environment

• Floor & foundation: Does the machine have a proper foundation, mounting anchor bolts, level base, stable floor support?
• Cooling and ventilation: Whether the heat dissipation is adequate
• Dust / grit / contamination: If the machine was in a harsh environment (grinding dust, coolant sludge), that accelerates wear
• Environmental control: Temperature fluctuations, humidity, presence of acids in coolant, etc., all degrade machine lifespan
• Spare parts availability: Ask whether consumables, wheels, bearings, seals are easy to source or whether the machine is “orphanned”
• Operator ergonomics, accessibility: Are critical maintenance points accessible or obstructed?

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4. Evaluation, measurement, and analytics

Once you have all the inspection data, use those to compare against acceptable thresholds and derive a “health score” or estimate remaining useful life.

• Wear margin: Compare measured geometries (flatness, straightness, runout, parallelism) to original specs and acceptable tolerances
• Backlash / precision losses: quantify how much backlash or lost motion exists, and whether it’s within your required tolerance
• Spindle life remaining: Based on bearing condition, vibration, noise, suggestions from the seller
• Upgradability / retrofit potential: If control electronics are obsolete, is it feasible to retrofit CNC or newer systems
• Cost of repair / reconditioning: From your inspections, list out major repairs needed (e.g. spindle regrind, guideway re-scraping, repacking of ways, controls replacement) and estimate costs
• Downtime / commissioning risk: If the seller must disassemble and transport, alignment and recalibration costs must be included
• Total cost of ownership (TCO): Sum purchase price + transport + repairs + spare parts + downtime, vs expected useful life vs alternative options

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5. Red flags & deal-breakers

While lesser defects can be negotiated, some are serious enough to walk away:

1. Heavily damaged or cracked base / casting
2. Spindle damage, severe bearing failure, or ambiguous spindle condition
3. Severe guideway or bed wear beyond repair (would require full re-scraping or replacement)
4. Control electronics in unrepairable / unsupported state (no spare parts, obsolete hardware)
5. Missing critical components (chucks, dresser, drives, encoders)
6. Unrecoverable misalignment or inability to re-calibrate after disassembly
7. Lack of documentation or parts history
8. Seller unwilling to allow testing or inspection
9. Environmental damage (corrosion, contamination) beyond economical repair

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6. Specifics to the TOS Hostivař BUA 25/1000

Since you mentioned that specific model, a few extra considerations:

• Given its age and discontinuation, spare parts might become scarce. That includes bearings, seals, electronic modules, encoder units, etc.
• The swing and distance between centers suggest a 1 m travel capacity—but ensure the specific machine (especially if retrofitted) still maintains this.
• If it has been retrofitted to CNC (as some listings show), check how well the retrofit has been integrated; interfaces, rigidity, feedback systems must be high quality.
• Ensure that any “CNC” designation is not superficial (i.e. just adding servo drives) — probe whether feedback loops, interpolations, axis linear encoders, calibration have been redone.
• Given its ~3-ton mass, transportation, rigging, demounting, and alignment will be nontrivial.

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7. Negotiation & final considerations

• Ask the seller to share the results of your test / inspection (or perform them in their presence).
• Use your repair / overhaul estimates as negotiation levers.
• Factor in transportation, lifting, alignment, installation in your budget.
• Insist on a “right-of-return” or limited warranty period (if possible) for major components.
• Consider hiring an independent inspector or consultant familiar with cylindrical grinders, especially older / specialized machines.
• Try to run the machine with your own test piece or your typical workpiece, rather than a “demo part” chosen to look good.