Table Saw Alignment

What

The throat plate, also referred to as the table insert, surrounds the blade where is passes through the table.  It’s job is to support the work close to the blade.  It needs to be adjusted so that it is level with the table surface.

Why

If the throat plate is not level with the surface of the table, then it can cause the following problems:

• The work can hang up on the leading edge of the throat plate or on the table at the trailing edge of the throat plate.
• The work can be lifted slightly higher than the table surface making the depth of cut inaccurate.

How

Most throat plates have four socket head set screws which can be used to adjust the height.  To ensure that work doesn’t hang up, it’s common to adjust the leading edge slightly below and the trailing edge slightly above the table surface.  Typically, this is done by placing a straight edge across the insert and adjusting the set screws while looking for tiny gaps.  As an alternative, feeler gauges can be used to judge the gaps.  A dial indicator makes the task very easy.

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This is the basic setup - the dial indicator mounted vertically with the stylus tip against the table surface.  Adjust the height of the dial indicator to obtain a good reading.  Zero the indicator.  Move the stylus to the insert near one of the adjusting screws.  Adjust the screw so that the dial indicator reads the same as it did on the table (zero).  Check the adjustment by moving the stylus back and forth between the table surface and the throat plate and observe the reading. 

Ed Bennett
ejb@tablesawalignment.com