April 9, 2022
Aside from the miter gauge and sled, one of the most valuable accessories you can have for your table saw is the zero clearance insert (ZCI). It can reduce tearing out and chipping of the wood piece and helps prevent jamming of the saw blade. But what is a zero clearance insert? Well, it is a throat plate replacement.
The table saw, of course, comes with a throat plate to ensure the safety of its users. Yet, sometimes, there is a gap between the throat plate and the table saw blade.
The zero clearance insert bridges this gap, ensuring that the distance between the nearest supporting surface and the saw blade is zero. For this reason, the insert is set as close as possible to the table saw blade without touching it.
The Zero Clearance Insert as Throat Replacement
The ZCI replaces the throat plate. It features almost the same size, thickness, and shape as the typical table saw throat plate. Besides, you will find ZCIs made of plastic, wood, MDF, and other materials. It gets installed around the blade. Thus, it has similar dimensions to that of the ordinary throat plate.
The primary purpose of the ZCI is to bridge the distance between the nearest surface support and the saw blade. Moreover, the ZCI opening fits the exact saw blade’s width. It leaves no extra clearance around the sides and front of the saw blade.
Advantages of Using ZCI
As mentioned above, the ZCI is one of the useful accessories for the table saw. If you don’t have one in your table saw, it will be best to install one. Below are the obvious benefits of using ZCI:
Reduces Chipping and Tearing out
The ZCI can reduce tear-out when cutting wood. If your table saw comes only with the standard throat plate, your workpiece will likely exhibit chip-out and tear-out. But if you replace the factory throat plate with a ZCI, you provide the wood piece with enough support to prevent the pulling away of wood fibers during the cutting process.
Remember that the lesser the open space around the saw blade, the lesser the probability of chip-out and tear-out. Thus, you improve the quality of your cuts.
Helps Prevent Jamming of Saw Blade!
The ZCI will prevent tiny wood pieces from falling onto the space around your saw blade during the cutting process. For this reason, the saw blade will not likely jam or kick back. Besides, if the gap gets filled with debris, this debris might cause the saw blade to stop, causing so much strain on the saw motor, burning out the motor.
Enhances Sawdust Collection
The ZCI ensures virtually almost zero opening around the saw blade. Thus, sawdust is prevented from lodging into the table saw and saw blade. Instead, the sawdust gets directed to the dust collection system, making the cleanup afterward easy.
Zero Clearance Insert’s Limitations
The abovementioned advantages might have convinced you of the benefits concomitant with the use of ZCI. Yet, the ZCI also comes with the following limitations:
Suited Only for Some Blade Types
You may think that you can use the ZCI for all types of saw blades. Yet, it is not the case, for it is only suited for saw blades with specific kerf. Hence, you can only install it when using certain types of saw blades. So, if you’re using various types of saw blades, it will be best to have several inserts at your disposal.
Over Time, You’ll See the Widening of the Clearance Gap.
Since there is the absence of clearance on ZCI, over time, a gap will begin to appear. Hence, you need to replace the old ZCI with a new one by that time.
Only Allows for Single Blade Angle
You will discover that the ZCI is only suited for use at a single saw blade angle. Thus, if you need to make a 45-degree angled cut, you must use a ZCI, specifically designed to fit the saw blade at that angle.
Frequently Asked Questions
Aside from knowing the pros and cons of using a ZCI on your table saw, it might also help if you are familiar with the following FAQs about the use of ZCI, for they might also be the questions you have in mind:
Is the ZCI a Better Option Than the Original Throat Plate of the Table Saw?
It is easy to say that the ZCI is better than the throat plate that comes with your table saw. Nevertheless, it doesn’t mean that the throat plate is no longer needed. It is better to keep your old throat plate and use it when you are engaged in simple cutting tasks or unconventional bevel cuts.
Since the ZCI gets only designed for a specific bevel cut, you get restricted with its use. Yet, the throat plate allows for various angle settings by allowing for more clearance when cutting. If you are not concerned about tear-out when cutting, you can also use the throat plate.
Is It Good to Use a ZCI With a Riving Knife?
An apparent problem quickly ensues once you use ZCI on your table saw, especially if you intend to use a riving knife. The reason is that the ZCI closes the gap or opening for the riving knife installation. The riving knife, of course, is best in preventing kickback.
Cutting a slot in the insert’s back to accommodate the riving knife would not be an option, for if you do that, you will cut the ZCI in half and compromise its integrity. You can solve this issue by cutting a slot to accommodate the riving knife without compromising the insert’s integrity.
You can use a drop router for cutting the necessary slot. You can mark the slot where you will install the riving knife. Then, cut along the mark using the drop router. You can cut along the insert’s rear to accommodate the riving knife using the drop router.
When you buy a table, you will get a complete device that you can quickly use after installing it. So, you basically don’t need many accessories to complete a cut. However, you can further enhance your woodworking activities by using a zero clearance insert and other must-have accessories such as the crosscut sled and miter gauge.
The ZCI is very useful, especially in bridging the gap between the table and the saw blade. As you read the advantages concomitant with the use of ZCI, you will quickly see the value of its use. Yet, after reading about the disadvantages of the ZCI, you might also want to think about whether you will need a ZCI in your cutting process.
Jason is a 40-year-old woodworker, carpenter and author who have been involved in the woodworking and woodcraft industry with 17 years of experience. He is expertise in technical aspects, woodcraft and furniture building projects.