What Is A Through Cut On A Table Saw?

There’s something about firing up the table saw in our woodworking shop, the speed at which the spinning blade reaches those 3000 – 4000 RPMs, the ease with which it cuts through the wood.  Whether ripping or cross-cutting, great power and multiple capabilities help move the project pieces along quickly.

I measure carefully, set the rip fence accordingly, and push the workpiece through the blade.  I watch the riving knife keep the kerf open, reducing, if not eliminating, the risk of kickback and injury.  I’ve always always been careful to wear our safety glasses when using this beast.

As you can no doubt tell, I like the table saw. 

What Cuts Can You Make With a Table Saw?

While this question has quite a number of answers, we can break it down into two main categories.

What is A Non-Through Cut On a Table Saw?

The cuts that come to mind with this question are:

  • Groove.  A groove cut, a trench or slot cut that does not go all the way through the wood, runs with the grain.  Generally speaking, the purpose of a groove is to allow another piece of wood, for instance, to move within and be guided by the groove.
  • Dado.  A dado cut, also a cut that does not go all the way through the wood, runs across the grain.  Made by a dado blade, the grooves made by it would be used for interlocking a second piece.  Interlocking joints are common joinery techniques in the making of shelves, cabinets, and doors.
  • Rabbet.  Similar to a groove and dado cut, also not going all the way through the wood, is at the edge of the wood.  Cut along the edge; this “tongue” is used in joinery for the making of boxes that do not require great joint strength or to attach the backs in cabinetry, or in the making of drawers in a chest of drawers for your bedroom.

In each of these instances, the wood remains a single piece rather than two after the cut is made, and the cuts are made for some joinery purpose.  While a groove can be cut with the standard table saw blade or perhaps with a slightly wider blade, the dado and rabbet cuts would require a dado blade.

For those who have yet to use a dado blade, it is a circular saw blade that makes wider cuts in wood than a standard blade can cut.  While you could use stacked circular saw blades for a dado cut (same brand and model to maintain identical diameters), the quality of the cut could suffer.  You are better off purchasing a dedicated dado blade.

For precision dado cuts, also, you’ll want your table saw to do the cutting rather than a router.  While a router is capable of making dado cuts, you would need to rely on a steady hand and strong woodworking skills to get a perfect cut.  The table saw is by far the better, if not best, choice for these cuts.

Do You Need a Riving Knife to Make Groove, Dado, or Rabbet Cuts?

This is one of the main differences between non-through cuts and through cuts, which we will address in a moment.

The purpose of a riving knife is to keep the kerf open as the workpiece is pushed through the blade.  Keeping the kerf open prevents the blade from grabbing the wood and kicking it back at your head or face, thus averting injury.  All table saws are now required to include a riving knife for this safety feature.

Since there is no kerf in any of these cuts, a riving knife would serve no purpose,  is not necessary, and may be removed.  The pressure on such cuts is simply forward and down, and the blade will have no closing kerf to grab for kickback as the cut is on the underside of the wood. 

What is a Through Cut?

Through Cut On A Table Saw

As you may have gathered by now, a through cut is one that creates two pieces, at least from one piece of wood.  It cuts all the way through as the workpiece is pushed through the blade.

However, there are a few important things to keep in mind for making through cuts.  They include:

  • The riving knife.  For through cuts, the riving knife is essential for safety purposes.  Kickbacks are nasty and can cause serious injury.  A riving knife has the advantage over the next item in that its position in relation to the blade is constant, perhaps a half-inch or so away from the blade, and either at the height of the blade or just below that height.  With a static position, the riving knife is always in position to serve its purpose.
  • The Splitter or Spreader.  Just as a riving knife keeps the kerf open, so does the splitter.  They tend to be higher than the blade and a bit further back from it than the riving knife.  Some spreaders will also have anti-kickback pawls that will hold the wood down and prevent it from being thrown back at you.  
  • The Blade Guard.  This feature encases it from above and prevents an errant hand, finger, or forearm from dropping onto the spinning blade.  When using a riving knife, you should also keep the blade guard in place as an added safety measure.
  • The Miter Gauge.  While this may not seem like a safety feature on your table saw, it is one, at least with regard to the workpiece and your project.  The keeper piece should always be in front of it when making a through cut, with the drop-off piece on the other side of the blade.  Your cut will tend to be more accurate, and you will not run the risk of the keeper piece being damaged in any way.
  • The Sled.  Again, not an obvious safety feature with your table saw, but see the comments above, re: miter gauge.  Same thing – protect the keeper workpiece, and have greater control of the cut for accuracy and trueness.
  • The Push Stick or Block.  Again, a safety feature.  Rather than use your hands to push the wood through the spinning blade, a push stick keeps your hand further from the blade that can take a finger.  Not all of us can afford a SawStop table, or cabinet saw ($1600 – $4800, depending on the model), so extra precautions need to be taken when it comes to through cuts.  However, even with a groove, dado, or rabbet cut, the push stick is still a necessary safety precaution.

Another adjustment needed on your table saw between through cuts and the non-through cuts mentioned above is the throat plate.  This is the piece through which the table saw blade protrudes above the table.  The standard plate is just wider than the standard blade;  the dado blade, of necessity, is wider to accommodate the wider dado blade.

There is also the zero-clearance plate (the name tells you what you need to know) that is narrower than the standard plate.  It is used when cutting small or thin wood pieces.  While some table saw manufacturers will include a zero-tolerance throat plate with the saw, many serious woodworkers simply make their own.  Swapping out throat plates is an easy task – remove one, insert another.

Those who are new to table saws and the different cuts they can make here’s a video of table saw basics.  It’s a bit long, at a little over 13 minutes, but it’s worth a watch.

Perhaps not necessary, but maybe helpful to illustrate a non-through cut; here is a 33-second video showing one.

We like to emphasize safety in the use of a table saw.  They are powerful and dangerous if you are careless, and there are many safety features to include in their use.  We don’t want you to be among the 67,000 estimated table saw accidents each year.

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