# Used CNC Inspection Checklist

Canonical URL: https://fundmyequipment.com/learn/used-cnc-inspection-checklist/
Last modified: 2026-05-29T19:39:17+00:00
Type: efin_guide

## Summary

Used CNC Inspection Checklist. Comprehensive guide.

## Content

Used CNC machine inspection requires more than just "does it power on." Spindle health, axis condition, control system status, and prior maintenance discipline all matter for resale value and remaining useful life. Here is what to check before financing a used CNC.

Spindle

Total spindle hours (request from control system)
Spindle bearing condition: vibration analysis, runout test, axial play
Spindle taper condition (BT40, CAT50, HSK63A, etc.): inspection of taper surface for damage
Tool changer operation: change time, alignment, tool clamping force
Drawbar pull-force test
Spindle temperature in run condition


Axis and ballscrews

Ballscrew backlash on each axis (X, Y, Z, and 4th/5th if equipped)
Way condition: scraping pattern, oil film, signs of wear
Slide alignment
Servo motor condition
Encoder condition (request error history)
Geometric accuracy: test bar between spindle and table, verify alignment


Control system

Controller make and model (Fanuc 0i, 30i, Siemens 840D, Mitsubishi, Heidenhain)
Control system software version
Memory and storage condition
I/O response time
Available CNC options (rigid tapping, high-speed machining, 5-axis sync, etc.)
Tooling library and offsets stored


Hydraulics and coolant

Hydraulic pump condition and pressure
Hydraulic oil condition (clarity, smell, water content)
Coolant tank condition and pump
Coolant flow at all flood ports
Through-spindle coolant (TSC) if equipped: pressure, filtration
Chip conveyor operation


Pneumatic and lubrication

Air pressure and filtration
Auto-lubrication system operation (way lube)
Auto-lube reservoir level and cycle
Air dryer condition


Operational tests

Run a known-good test part (request from prior owner)
Verify dimensional accuracy of test part on a CMM if available
Surface finish on a test cut
Repeatability test (run same part 5 times, measure variance)
Tool change cycle time
Rapid traverse speeds on each axis
Cycle through all canned cycles (drilling, tapping, pocketing)


Documentation to request

Full maintenance log (preventive maintenance schedules followed?)
Prior repair invoices and parts replacements
Control system error history
Spindle hours and total run time
Original manuals and electrical schematics
Any remaining warranty
Title and lien status


What to budget for inspection
Qualified CNC service technician: $300-800 depending on machine complexity and travel. OEM service rep (Haas, Mazak, Okuma, DMG Mori, etc.): $500-1,500 but more authoritative. Vibration analysis specialist: $250-500 add-on for spindle diagnosis.

Red flags

Spindle hours over 25,000 without documented rebuild
Excessive axis backlash (over 0.001" for VMC, 0.002" for larger HMC)
Active control system alarms not previously diagnosed
Maintenance log gaps over 6 months
Damaged spindle taper (cuts, gouges, fretting)
Aftermarket control retrofit without OEM support (orphaned electronics)
Title issues or unclear ownership history


What lenders require
Used CNC over $50,000 typically requires a third-party inspection. The lender wants to see: spindle hours, control system status, maintenance discipline, and remaining useful life estimate. Some lenders maintain an approved-inspector list.

Apply for used-CNC financing at /apply/.