I was surprised to see the number of Instructables tutorials on table saw inserts but none for miter saw inserts. While I'm sure there are many zero clearance tutorials out there, I thought I'd share the video I made documenting the process of how I made my very own zero clearance miter saw insert using just a $2 piece of wood.
Step 1: Reduce Tearout
If you’re wondering why do I need a zero clearance insert for my miter saw? I have just one word for you: tearout. Ever noticed that the wood fibers seem all frayed along the cut when using your miter saw or table saw? That’s tearout. The wood fibers get ripped away by the blade because of the small gap around the blade. You can easily fix that by making your own miter saw zero clearance insert.
Step 2: Check Out the YouTube Video
Step 3: Remove the Existing Insert
Start by unscrewing the existing insert. Make sure to note which piece goes on which side ;)
Use this opportunity to clean out any debris with your shop vac.
Step 4: Measure & Cut
Measure the width and length of the cavity for your new insert. Be precise! In my case, the measurements were 2-1/16" by 13-3/8".
You'll need a piece of hardwood that matches the depth of your existing insert. In my case that was 1/4". I bought a 1/4" hobby board made of poplar at Home Depot for under $2.
Use the table saw or miter saw to make your cuts.
Step 5: Sand Down the Edges and Bottom for a Perfect Fit
The piece you just cut may not fit, bu that's ok. Actually, that's good. You want a snug fit.
Lay a piece of sandpaper flat on a surface and sand the edges of your new insert. Keep trying to fit it and see where needs to be sanded until the fit is perfect.
Check that the surface is flush. If not, sand the bottom of the insert until the fit is flush to the surface.
Step 6: Mark and Drill Countersunk Screw Holes
Use the old insert to mark the screw holes on your new insert. I used a screwdriver to mark the wood then made the holes using a drill press.
In order to determine which drill bit to use, find the one that matches the hole size on your existing insert.
Finally, use a countersink bit to ensure that the sure the screws will sit flush with the surface.
Step 7: Cut the Kerf
Screw in your new insert using the old screws and make sure the surface is completely flush, with no screws protruding.
Check your blade for square (use a carpenter's square) before you make your cut. I started with a shallow pass, then fully plunged the blade to make the kerf in my new insert.