Applies to fixed-head planers, such as:

• G0453 Series
• G0454 Series
• G1033 Series

• G1021 Series

• SB1108 and SB1109

Overview

If your planer produces boards that are uneven in thickness or tapered from one side to the other, the table may no longer be parallel with the cutterhead. Proper table parallelism is critical for producing accurate, consistent results.

This article explains how to inspect the table and provides a general overview of the adjustment process.

Important: Adjustment specifications vary by model, model variation, and manufacture date. Before rotating a table-height sprocket or making a column adjustment, identify the complete model number and refer to the applicable owner’s manual. Do not assume all machines within the same model series use the same sprocket direction or amount of movement.

Symptoms

Your planer may need a table parallelism adjustment if:

• Boards are consistently thicker on one side than the other.
• Thickness measurements vary across the width of the same board.
• Boards come out tapered from front to back.
• Planed material remains uneven after verifying the workpiece, cutterhead knives or inserts, bed rollers, and other setup adjustments.

Tapering or uneven thickness can also be caused by warped stock, improperly installed knives or inserts, bed roller height, feed component adjustments, or loose table locks. Inspect these conditions before changing table parallelism.

Table Parallelism Tolerances

Most later models use the following maximum tolerances:

Side-to-side alignment is the most critical because it directly affects the finished thickness across the workpiece.

Front-to-back alignment is less critical because the feed rollers, pressure bar, and chip breaker are adjusted relative to the table position.

Important: These tolerances are not universal. For example, the original G1021 manual allows up to 0.004 inch of side-to-side deviation. Always use the tolerance listed in the owner’s manual for your exact model and manufacture date.

Tools Required

Depending on the model, you may need:

• W1218A Rotacator or equivalent dial indicator
• Flat hardwood gauge block and feeler gauges, if a dial indicator is unavailable
• #2 Phillips screwdriver
• Metric wrench or socket set
• Metric hex wrench set
• Permanent marker

Fastener types and sizes vary by model. Some machines use a 12 mm wrench or socket, while others use a 14 mm wrench or socket. Hex wrench requirements may also vary.

For the most accurate measurements, Grizzly recommends using the W1218A Rotacator, a magnetic-base setup tool designed for planer setup and other precision machine adjustments.

Safety

⚠️ Disconnect the machine from power before beginning any inspection, measurement, or adjustment.

Wait for all moving parts to stop. Planer knives and cutterhead inserts are extremely sharp. Keep your hands away from cutting edges and use care when positioning a gauge block or dial indicator beneath the cutterhead.

Inspecting Table Parallelism

Begin with a test cut:

1. Select a flat, properly prepared workpiece.
2. Plane the workpiece.
3. Measure its thickness at several points along both sides and across its width.
4. Compare the measurements.

If the workpiece is consistently thicker on one side, the table may be out of parallel with the cutterhead. Front-to-back taper may also indicate a parallelism problem, but other causes such as snipe, workpiece distortion, or feed-component adjustments should be ruled out first.

For a more accurate inspection:

1. Disconnect the planer from power.
2. Verify the knives or cutterhead inserts are properly installed and adjusted.
3. Position a Rotacator or equivalent dial indicator between the table and cutterhead.
4. Measure both sides using the same cutterhead reference point and the procedure provided for your model.
5. Compare the measurements.
6. If necessary, use a flat hardwood gauge block and feeler gauges as an alternative.

If the difference exceeds the tolerance specified for your machine, the table requires adjustment.

Understanding Table Parallelism

Side-to-Side Parallelism

The table should remain parallel with the cutterhead across its width. On most later models, the maximum allowable deviation is 0.002 inch.

This alignment has the greatest effect on the finished thickness of the workpiece.

Front-to-Back Parallelism

The table should also remain reasonably parallel with the head casting from front to back. On most later models, the maximum allowable deviation is 0.020 inch.

Because the feed rollers, pressure bar, and chip breaker are adjusted relative to the table, front-to-back alignment is important even though its tolerance is generally less restrictive.

How the Adjustment Works

These planers generally provide two types of table adjustment:

• Coarse adjustment by repositioning the table-height chain on one or more sprockets
• Fine adjustment by loosening the table-to-column mounting fasteners and repositioning the table

The amount of movement produced by each sprocket tooth varies by model. It is commonly either approximately 0.008 inch or 0.016 inch.

The direction of movement also varies. On some models, clockwise rotation lowers the table. On other models, clockwise rotation raises it.

Confirm the correct tooth movement and rotation direction in the owner’s manual before proceeding.

Common Model Differences

For other G0453, G0454, G1033, or G1021 variations, verify the procedure in the applicable owner’s manual before rotating a sprocket.

Adjusting Table Parallelism

1. Disconnect the machine from power.
2. Remove the applicable motor access panel or cabinet panel.
3. Locate the table-height chain and sprockets beneath the table.
4. Determine which side or portion of the table requires adjustment and how much correction is needed.
5. Confirm the following specifications for your exact model:
   • Allowable table-parallelism tolerance
   • Approximate movement per sprocket tooth
   • Correct rotation direction
   • Required fastener sizes
   • Fine-adjustment procedure
6. Mark the original position of the chain and sprocket before making any changes. Taking a clear reference photo is also recommended.
7. Loosen the idler sprocket and applicable chain-tension or lock fasteners only enough to move the chain away from the sprocket being adjusted.
8. Move the chain away from the selected sprocket so the sprocket can rotate independently.
9. Rotate the sprocket one tooth in the direction required for your model, then reinstall the chain around the sprocket.

Important: When adjusting an entire side of the table, the corresponding sprockets may need to be moved equally. Keep an accurate tooth count so the affected columns remain synchronized. Follow the model-specific procedure to avoid twisting the table.

10. Make sure the chain is seated correctly on every sprocket.
11. Retension the table-height chain and tighten the idler and lock fasteners.
12. Tighten all table-mounting fasteners before measuring again.
13. Recheck table parallelism.
14. Repeat the coarse adjustment if necessary.
15. Once the alignment is within the coarse-adjustment range specified for the model, use the table-to-column mounting fasteners (or Micro-Adjustment screws) for fine adjustment.

16. Recheck the table at several points and verify it is within the applicable side-to-side and front-to-back tolerances.
17. Confirm the table-height chain is properly tensioned and reinstall all access panels before reconnecting the machine to power.

Helpful Tips

• Tighten all fasteners before taking a new measurement. Loose fasteners can produce inaccurate readings.
• Make one small adjustment at a time and measure after each change.
• Mark the original sprocket and chain positions before moving anything.
• Do not allow the chain to become excessively loose. If it falls off all the sprockets, reinstalling it without changing the table alignment can be difficult.
• Do not use the sprocket direction from a different model or manual revision.
• Small adjustments may be needed on more than one column to achieve the correct side-to-side and front-to-back alignment.
• If your machine does not match the fasteners, sprocket arrangement, or adjustment method described in its manual, stop and contact Product Support before continuing.