Quick Answer

If the sanding belt on your Ferrex MM4115A Belt and Disc Sander is jamming, slipping, or moving off the rollers, it is usually because the belt requires adjustment. Before using the machine, check that the belt is correctly aligned and adjust the tracking if necessary using the supplied 3 mm Allen key.

Tip: Always check the belt tracking before using the sander for the first time or after fitting a new sanding belt.

Before You Begin

For your safety:

• Switch the sander OFF.
• Disconnect the machine from the mains power supply.
• Allow all moving parts to come to a complete stop.
• Never adjust the belt while the machine is running.

Important: Operating the sander with a misaligned belt can cause premature belt wear or the belt to come off the rollers.

Check the Belt Alignment

Before making any adjustments:

1. Turn the sanding belt by hand.
2. Observe whether the belt runs centrally on the rollers.
3. Check that the belt moves smoothly without drifting to either side.

If the belt begins to move off the rollers or feels loose, it will require adjustment.

Adjust the Belt Tracking

To adjust the belt:

1. Locate the 3 mm Allen Key

Use the 3 mm Allen wrench, which is the smallest Allen key supplied with your machine.

2. Locate the Adjustment Points

Find the three adjustment holes on the machine used for belt tracking.

3. Make Small Adjustments

Insert the 3 mm Allen key into the adjustment holes.

Make small adjustments until the sanding belt:

• Runs centrally on the rollers.
• Does not drift to either side.
• Moves freely without slipping.

Turn the belt by hand after each adjustment to check the alignment.

Tip: Small adjustments usually produce the best results. Avoid making large adjustments at once.

Before Using the Machine

Once the belt is correctly aligned:

• Confirm the belt remains centred while turning it by hand.
• Check that the belt is correctly tensioned.
• Ensure all tools have been removed from the machine.
• Reconnect the power supply and operate the sander normally.

My Belt Still Slips or Jams

If the belt continues to slip after adjustment:

• Check that the sanding belt has been installed correctly.
• Inspect the belt for signs of wear or stretching.
• Ensure the belt is the correct size for the MM4115A.
• Confirm the rollers rotate freely and are free from debris.

If the problem persists, please contact our Customer Support team for further assistance.

Frequently Asked Questions

Why does my sanding belt keep slipping off?

The most common cause is incorrect belt tracking or tension. Adjust the tracking using the supplied 3 mm Allen key until the belt runs centrally.

Should I check the belt before first use?

Yes. We recommend checking the belt alignment before using the sander for the first time and whenever a new sanding belt is fitted.

Can I adjust the belt while the machine is running?

No. Always switch the machine off and disconnect it from the mains power supply before making any adjustments.

Why should I turn the belt by hand first?

Turning the belt manually allows you to check its alignment safely before powering on the machine.

What should I do if the belt still won't stay centred?

Inspect the sanding belt for wear or damage and ensure it is fitted correctly. If the issue continues after adjustment, contact our Customer Support team for further assistance.