Making a zero clearance insert is a great project for anyone with a table saw. A zero clearance insert ensures your workpiece is well supported throughout the entire cut, and that's especially important for small parts. Zero clearance insert's are available for purchase, and you'll spend about $20 per blank. Usually you'll need more than one insert (i.e. one for the everyday-use blade and another for your dado stack), and that means you can easily spend $40 or more. Instead, I'll show you how to make your own zero clearance insert at a fraction of the cost.
First, remove the OEM throat plate from your table saw and trace its outline onto 1/2" plywood. Cut along the outside of the traced line.
Next, set up your router with a flush trim bit - a router bit that features a bottom-mount guide bearing.
Use the OEM throat plate as a template for the flush trim bit to follow. If you don't have a router, you can use a sander to achieve similar results.
Test the fit of the insert in the table saw and sand the edges as necessary to achieve a snug fit.
Lower the blade to it's lowest height below the table. Many table saws can't lower the blade far enough to fully seat a blank insert. To start the kerf cut, I clamped my insert overtop the OEM throat plate. Then start the saw and slowly raise the blade through the new insert.
Once the blade cuts through the top of the insert, stop the saw and replace the OEM insert with the zero clearance insert. Start the saw and carefully raise the blade to it's full height to complete the kerf cut.
I then removed the insert and used a jigsaw to extend the kerf cut to allow room for my riving knife to fit through. The riving knife itself is an important safety feature, but it also is necessary to attach the blade guard.
My table saw has magnets in the top to hold the OEM throat plate secure. I cut roofing nails so that they wouldn't penetrate through the insert and then drove them into the bottom of the insert to align with the magnets. I then sanded the insert to be flush with the top of my table saw. In hindsight, I realized that instead of nails, a better solution is to use 1/2-in.-long screws so that you can more easily adjust the height of the insert.
Lastly, I drilled a grab hole through the insert so that I can easily remove it .
Ethan Hagan is the primary editor at One Project Closer. Ethan spends most of his days shadowing real contractors on actual job sites and most of his nights writing about it. OPC also provides Home Depot Coupons to help you save on your next home improvement project. If learning and interacting with pro contractors sounds like something you’d enjoy, like OPC on Facebook.