How can I tell if the problem is the spindle or the Anderson router?

If symptoms scale with RPM (especially unloaded), or the spindle runs hot at idle, it typically points to the spindle. If symptoms change with gantry position, axis direction, or only appear under load, it may be machine-side (workholding, rigidity, motion components, or resonance).

What symptoms usually indicate an internal spindle issue?

Common spindle indicators include vibration that increases with RPM, abnormal heat rise when unloaded, measurable runout at the taper/nose, and noise that follows RPM changes (whine, rumble, grinding).

What symptoms usually indicate a router or machine-side issue?

Machine-side indicators include vibration or finish changes that vary by axis position, chatter only during cutting load, issues tied to specific directions of travel, and electrical/drive alarms related to axes or motion control.

Is It the Anderson Router or the Spindle?

Q: Do you repair the Anderson CNC machine itself?

No. Atlanta Precision Spindles repairs the spindle assembly only. We do not service the router frame, linear rails/ball screws, drives, controls, wiring, or other machine-side components.

(How to Tell the Difference Before You Pull It)

When cut quality drops or vibration increases on your Anderson CNC, the big question is:

Is the issue in the machine — or inside the spindle?

Most Anderson America routers use high-speed electrospindles, built In-House. Both the router structure and the spindle assembly influence finish quality, so proper diagnosis matters.

Symptoms That Usually Point to the Spindle

🔹 Vibration Increases with RPM (Even Unloaded)

If vibration gets worse as RPM rises — especially without tooling installed — that strongly suggests:

Bearing wear
Loss of preload
Rotor imbalance
Internal contamination

Machine structure issues usually don’t scale linearly with RPM like this.

🔹 Spindle Running Hot at Idle

If the spindle heats quickly without cutting load:

Internal friction is increasing
Grease may be breaking down
Bearings may be near failure

That’s almost always internal.

🔹 Measurable Runout at the Taper

Check with a tenths indicator at the taper:

Consistent measurable runout at the spindle nose
Runout that does not change with gantry position

That typically indicates spindle shaft or bearing wear.

🔹 Noise Directly from the Spindle Housing

High-pitched whining, grinding, or cyclic rumble that follows RPM changes is usually bearing-related.

Symptoms That Often Point to the Router (Not the Spindle)

🔸 Vibration Changes by Axis Position

If finish varies depending on:

Gantry position
Table location
Direction of cut

You may be dealing with:

Linear rail wear
Ball screw issues
Frame resonance
Loose mounting hardware

🔸 Chatter Only Under Cutting Load

If the spindle runs smoothly unloaded but chatters only when cutting:

Tool deflection
Workholding issues
Dull tooling
Feed/speed imbalance
Machine rigidity limits

🔸 Electrical or Drive Alarms

If you see:

Servo faults
Axis following errors
Drive overload alarms

That’s machine-side, not spindle-side.

Quick Diagnostic Process

Before removing the spindle:

✔️ Remove tooling and run at multiple RPMs
✔️ Check spindle nose temperature rise
✔️ Measure runout at taper
✔️ Move gantry to different positions and test again
✔️ Lightly load the spindle and observe changes

If the issue follows RPM regardless of machine position, it’s likely the spindle.

If the issue follows machine position or axis movement, it’s likely the router.

Why Proper Diagnosis Matters

Pulling a spindle unnecessarily causes:

Production downtime
Shipping costs
Lost time if the spindle checks out healthy

But delaying spindle repair when bearings are failing can:

Damage the shaft
Overheat the stator
Multiply repair costs

Early diagnosis saves money either way.

Important Disclaimer

Atlanta Precision Spindles repairs the spindle assembly only — not the CNC machine itself.

We do not service the router frame, linear rails, ball screws, controls, wiring, drives, or other machine components. Our work focuses strictly on precision spindle inspection, rebuild, and restoration.

Precision Spindle Repair