What Is a Zero Clearance Table Saw Insert Used For?

Last modified on September 11, 2021
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A zero clearance insert (ZCI) is one of the most helpful table saw attachments available. Inserts with zero clearance increase cut quality while also making your saw safer to use. This great even if are a beginner. Check out our selection of best starter table saws.

A zero clearance insert is one that perfectly fits the blade width. One can be made by raising the blade gently through an uncut insert.

It covers the gap left by the metal insert that comes with the saw, preventing objects from falling through the hole and, more significantly, reducing chip-out by guaranteeing that the piece is supported, preventing chips from being pushed away from the board. However, it isn’t flawless, so if you care, put in your sacrifice piece.

In general, the less free area beneath your workpiece, the more control you have while cutting.

Benefits of Using a Zero Clearance Insert

To keep tiny bits of wood from dropping through the crack. This reduces the risk of table saw kickback, which can cause serious injury. It also keeps wood from slipping into the crack and clogging the saw blade. If a piece of wood falls in, it may become lodged in the saw blade, causing it to stop spinning. This puts a lot of loads on the table saw motor, which might cause it to burn out.

To act as a backing to prevent chip-out on the cut’s backside. Because the workpiece is supported on all sides, ZCI’s decrease tear out and chipout. As the blade moves through the workpiece, the support prevents wood fibers from being pushed away from the workpiece. The less free area beneath your workpiece, the more control you have over the cut and the cut quality.

Improved sawdust collecting. There is almost no way for sawdust to return to the table saw when using a ZCI. The sawdust is almost entirely guided down the dust chute, resulting in less mess and more straightforward cleanup.

Is Zero Clearance Insert Better than The Throat Plate?

There isn’t a single situation when a ZCI wouldn’t be preferable. However, the presence of ZCIs does not imply that the throat plate is ineffective. Making and storing ZCIs for each saw blade and bevel angle is a pain. The typical throat plate is therefore convenient for non-critical cuts or cuts with unusual bevel angles.

The throat plate is intended to allow the saw blade to pass through the complete range of bevel angles on the table saw. It has more clearance around the saw blade, allowing for additional angle adjustments.

Conventional throat plates are more practical to use if you’re making a lot of one-off cuts with varied bevel angles and cuts.

Limitations of Zero Clearance Inserts

Because a ZCI is customized to a particular saw, blade type, and bevel angle, it is only used for cuts that meet those requirements. A ZCI can’t be used on any other cuts once it’s been produced for a straight-on 90° cut. You can’t utilize your 90° ZCI if you need to create a 45° bevel cut.

Because each zero clearance insert is only appropriate for one bevel angle, you’ll need a lot of these to cover the most frequent bevel angles. And if you’re using dado blades on your table saw, it’ll be even more so. Check out our selection of table saws with dado blades.

Also, because of the lack of clearance on these inserts, they will wear out with time. Over time, the saw blade gap will enlarge, requiring a new one.

Zero Clearance Insert with A Riving Knife

There is no hole for the riving knife when you build your own ZCI. When you wish to utilize your ZCI with the extra safety of a riving knife, this presents an issue. The most specific device for avoiding kickback is a riving knife. You can’t merely cut a hole for the riving knife at the rear of the insert. The ZCI would be nearly reduced in half if you did that, jeopardizing its structural stability.

Cutting a slit for the riving knife while maintaining the ZCI’s integrity is the answer. Using a drop router to create the slot where the riving knife lifts with the blade is the easiest technique to cut the gap. Mark the length of the riving knife and cut the aperture with the drop router

The riving knife opening can alternatively be cut with a bandsaw or a jigsaw. However, you’ll wind up cutting the insert practically in half with any of those saws. To fix this, glue a strip of wood to the back of the insert to seal the gap.

Getting an aftermarket ZCI might make things simpler because the groove for the riving knife opening is already cut.

Aftermarket Zero Clearance Inserts

Zero clearance inserts are available from a variety of manufacturers for most table saw models. They’ve been pre-cut for a saw blade as well as a riving knife. It’s simple to get a ZCIs for your table saw if you know the model and the blade or dado you’ll be using.

How to Make a DIY Zero Clearance Insert

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