Table Saw Alignment

What

The rip fence needs to be parallel to the miter slot.  This ensures that it will be parallel to the blade for safe and accurate rip cuts.  The surface of the fence should also be square with the table surface. 

Why

A few classic symptoms of poor fence alignment

1. Burning of the cut edge
2. Board wandering away from the fence during a rip cut
3. Sawdust being thrown up at the operator
4. Kickback

Sound familiar?  Yep, these are the same symptoms as poor blade alignment.  So, if you didn’t use the miter slot as your alignment reference, then how would you decide what was wrong?  Does the blade need alignment?  Does the fence need alignment?  Impossible to decide unless you use an independent reference: the miter slot.

If the face of the fence isn’t square to the surface of the table, then the width of cut can change depending on the thickness of the work being cut.  This can be especially critical when using the fence as a stop for making shoulder cuts on a tenon.  When the board is flat on the table it registers one way and when it’s on edge (taller) it registers another way.  The shoulder cuts come out uneven, requiring the joint to be re-worked by hand.

How

The Video… 

The Text…

Aligning the fence

Place the stylus against the surface of the fence and zero the indicator.

Slide the jig down to the other end of the fence while observing the reading on the dial indicator.  It’s not unusual to notice considerable variation in the surface of the fence.  The goal is to minimize the variation, even if there are some bumps or bowing.  Check your owner’s manual to determine how your fence is adjusted.

If, after making adjustments, there is still more than 0.005″ of variation then the quality of the cut will likely suffer.  If the variation  is more than 0.015″, then it could become a safety issue and something should be done to fix the problem.  Some fences have replaceable faces.  Some can be machined.  Others should just be replaced. 

Some people believe that it’s important to adjust the fence so that the far end is slightly further away from the slot.  If you do this, it should be no more than 0.015″ along the entire length of the fence.  If you leave more room you risk having the work wander away from the fence during the cut.  Personally, I align the fence parallel to the miter slot.

Fence Squareness

The photo above shows the Angle Attachment Gage being used to measure squareness of the fence.  If you don’t have an Angle Attachment Gage, then you can use a square to sight any gap.  Some fences have an adjustment for squareness and some don’t.  If you fence does not have an adjustment, then perhaps the faces can be replaced or machined. 

Micro-adjusting the position of the fence

Sometimes it’s necessary to move the fence by a very small measured amount.  A dial indicator jig makes this very easy to do.

Use calipers to adjust the pointer

An accurate rip fence scale is a tremendous time saver.  And, since changing the blade will often require re-calibration, it’s a good idea to learn a method that is accurate, easy, and fast.   This is yet another good reason to have dial calipers.

Make a rip cut and measure the width of the board with your calipers.  Then adjust the pointer so that it agrees with the measurement.  Could anything be easier?

Ed Bennett
ejb@tablesawalignment.com