How-To Align a Table Saw Blade to Miter Slot

Before starting any project, it’s important to take a few minutes to make sure all of your equipment has been properly adjusted. Your table saw will give the best results if the miter slot and the rip fence are adjusted parallel to the blade. If either of these are not parallel, your cuts and your finished work will be lower in quality, and the risk of kickback will be increased. Here’s how to make sure your table saw blade is aligned to the miter slot.

1. Disconnect the saw from the power source: A common sense step that is so easily forgotten when we’re excited to start a new project

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Cabinet-style Table Saws

1. Use an adjustable square to measure the distance from the miter slot to a single tooth on the blade. It is generally easier to check on the opposite side as the blade tilts because you can see the end of the square better when the blade is tilted. Make sure that the face of the adjustable square is even along the miter slot. With the end of the adjustable square just touching the edge of the tooth, lock the square in place, and then mark the tooth with a felt tip pen.

2. Rotate the blade towards the other end of the table insert. Slide the adjustable square down and compare the distance using the same tooth. If there is a gap, measure it with a feeler gauge. If it is closer, then reset the square using the rear position and measure the gap at the front position. Place a piece of masking tape on the table where you measured the gap, and write the measurement on the tape.

3. Tilt the table to 45° and repeat these steps. If the blade is not parallel within specifications at one or both positions, then it will need to be adjusted depending on the type of table saw you have.

Cabinet-style table saws have the trunnions mounted to the cabinet, so adjustments are normally performed by loosening the bolts and moving the table.

1. Locate the bolts that hold the table to the cabinet. They are typically located at the 4 corners of the cabinet. Carefully loosen these bolts about 1/2 to 3/4's of a turn. You want them to be just loose enough that they can move when you tap the table edge with a dead blow hammer. If you loosen them too much it will be harder to hold any adjustments you make before the bolts get re-tightened.

2. Gently tap the table in the needed direction using a dead blow hammer once the bolts are loose. Recheck the alignment with the adjustable square and continue making small adjustments until everything is aligned. Once you are satisfied with the adjustment, tighten the table mounting bolts. Double check that nothing moved when you tightened the bolts.

3. Make a second type of adjustment if the initial measurements are different at 90° and 45°. If this is the case, then you will need to add or remove shims from between the table and the cabinet or trunnions. The shims used are normally U-shaped. This allows them to be removed or added without completely removing the mounting bolts.

4. Adding shims under the 2 rear table corners will move the rear of the blade further from the miter slot. Adding them under the 2 front corners will move the front of the blade further from the miter slot. You should measure from the miter slot on the side that the blade tilts away from. If for some reason you measured on the opposite side, then shimming the table will have the opposite effect.

Contractor- and Hybrid-style Table Saws

Contractor- and hybrid- style table saws have the trunnions mounted to the underside of the table, so adjustments are performed by moving the trunnions.

1. Loosen the bolts that hold one of the trunnions and tap it sideways to bring things into alignment. Access the trunnion and remove any covers or panels to expose the trunnion bolts. Loosen the bolts about 1/2 to 3/4's of a turn.

2. Gently tap the trunnion on the side to move it in the needed direction using a hammer and a drift or punch. Recheck the alignment with the adjustable square and continue making small adjustments until everything is aligned. Tighten the trunnion mounting bolts and replace any covers once you are satisfied with the adjustment. Double check that nothing moved when you tightened the bolts.

3. Make a second type of adjustment if the initial measurements are different at 90° and 45°. Unlike cabinet-style, trunnions are mounted to the underside of the table When you add or remove shims, only shim a small amount. This will allow you to sneak up on the perfect alignment without going past. Make sure you only loosen one bolt at a time so the direct side to side adjustment of the table or trunnions is not affected. Re-check your measurements and then add or remove more shims as needed until you are satisfied with the alignment.

 Double check that all bolts are tight, tighten the trunnion mounting bolts and replace any covers. Then you’ll be set to start your next project and make some sawdust!