24/09/2025 By CNCBUL UK EDITOR Off

Avoid Costly Mistakes: Professional Tips for Purchasing a Pre-Owned / Second-Hand / used SKODA E20 Powered Rotary Table

Here’s a guide—tailored to powered rotary tables used on boring machines (such as a Skoda E20 model or equivalent)—to help you avoid expensive mistakes when buying a used unit. Even though “rotary table” seems simpler than a full CNC, there are many hidden wear issues and integration pitfalls. Use this as a checklist when inspecting or negotiating.

Key Background / Reference Data

Before you step on site, know what “normal” looks like for a Skoda E20 (or similar heavy-duty rotary table) so you can call out exaggerations. Some known data points:

One listing shows a Skoda E20 powered rotary table 80″ × 80″ with 44,000 lb (≈ 20 metric ton) capacity.
Another listing for Skoda E20 shows table dimensions 2000 × 2000 mm with 20 ton load capacity.
A used listing shows Skoda E20 has table weight ~ 9,350 kg for a 2000×2000 mm table.
The “E20” name is used for heavy duty rectangular / powered rotary tables with large capacity.

Thus, if someone offers a “Skoda E20” that claims a 100 ton load, or extremely fast indexing, you should demand proof and test carefully.

What to Inspect / Test On-Site

1. Documentation & History (First Gate)

Maintenance / repair logs: when bearings, drive gears, clamping surfaces were serviced
Overhaul or refurbishment records
Electrical / motor / gearbox schematics
Control / indexing system backups, software / parameter files
Past usage: how often used, loads carried, shift schedule
What comes with sale: power cables, control modules, spare motors/gears, mounting hardware

If the seller cannot provide credible history, you should discount heavily.

2. Visual / Structural Inspection (Before Powering Up)

Check the table top / indexing surface for wear, scoring, pitting, or misalignment.
Inspect clamping / locking surfaces (if hydraulic or mechanical clamps) for wear or damage.
Check the drive motor / gearbox housing for oil leaks, seal damage, cracked housings.
Inspect the brushes / slip rings / electrical connections (if applicable) for corrosion or wear.
Open the motor / gearbox housing (if allowed) and look for internal wear, chipped gears, metal chips.
Check the mounting surfaces / base frame for misalignment, cracks, distortions.
Inspect the support structure, bearings, raceways, cross-members for signs of stress or fatigue.
Examine cables, connectors, and wiring for damage, insulation wear, corrosion.

3. Power-Up & Basic Motion / Rotation Tests

If allowed, power up and test motion (no heavy load):

Test indexing or continuous rotation: rotate the table (360° or incremental) and watch motion smoothness
Reverse direction multiple times; measure backlash in the drive (e.g. via dial indicator)
Listen for noise: gear whine, metallic scraping, irregular pitch changes
Run at different speeds (if multiple speed settings exist) and check for consistency
Observe drive motor behavior: current draw, temperature, vibration
Engage / disengage the clamping or locking mechanism (if present) and verify full engagement / release
Test stop accuracy: command stop at known positions, see if the table returns to exact stop location

4. Load & Stability Test (If Possible / Safe)

Under light load (if seller allows a test load):

Mount a representative workpiece or dummy load; rotate or index under load and check for deflection, vibration, drift
Check radial runout of workpiece after indexing under load
Test if clamping holds the position firmly under torque
Run extended or repetitive cycles to test thermal stability or drift

5. Accuracy & Test Measurements

Use a fixed indicator (dial test indicator) on a mounted bar to check radial and axial runout over full rotation
Index back to the same position multiple times; measure the deviation (repeatability test)
At various rotation angles, measure runout to detect ellipticity or gear wear
For inclined or tilted mounted work, check tilt / flatness over the table surface
Warm the table (run for some time) and re-check to see if drift occurs

6. Gearbox, Motor, & Electrical System Checks

Inspect the gearbox: gear teeth condition, backlash between gear stages, oil level / quality
Check motor: bearings (listen / feel), shielding, connection integrity
If using slip rings or brushes for feedthroughs, inspect for wear, continuity, signals
Test limit switches, sensors, encoders, position feedback devices
Check the condition of cabling (flex, insulation, connectors) from motor to control system

Hidden Costs / Common Failure Modes to Budget For

Worn bearings or bearing replacement in the table or gearbox
Gear tooth wear / gear replacement or re-grinding
Re-scraping or lapping of table surfaces
Motor / drive replacements or rewind
Control / encoder or feedback module failures
Clamping system overhaul (hydraulic seals, pistons, mechanical latches)
Electrical wiring replacement, connectors refurbishment
Foundation alignment or correcting mounting distortions
Calibration, alignment, precision testing after installation
Spare parts scarcity for Skoda or niche rotary table components

Budget a refurbishment reserve (e.g. 10–20% or more) to cover surprises.

Negotiation & Contract Safeguards

Require a testing / acceptance period where you can run index / rotation tests, measurement checks before final payment
Hold back part of payment until acceptance criteria (runout, backlash, repeatability) are met
Demand delivery of all documentation: drawings, control / motor wiring, gear specs
Secure a condition disclosure from the seller listing known defects, wear, prior repairs
If possible, negotiate a short warranty on the drive system, clamping mechanism, motor
Clarify responsibilities for transport, mounting, alignment, leveling
Include any spare gears, motors, clamping parts if available