Are you getting a lot of tear out on the cuts you make with your miter saw? You need to build an auxiliary fence to help support the back and bottom of your workpiece. This will make the gap under the workpiece where the blade passes through narrower. By doing this, there is more support for the wood fibers, which reduces tearout. It’s super simple and can be done very quickly, especially on a saw that it not permanently mounted in a workstation. Like mine. You will probably make a fence like this at least a couple of times in your career.
I have a Kobalt 10″ Sliding Compound Miter Saw. For me, this saw really gets the job done. But out of the box, it is set up for rough cuts. It needs some help if you want to do any sort of finish or fine work. So let’s get that fence built.
Use a piece of scrap and make a test cut. You can use this to compare the cuts made with the new fence in place. Save the rest of the scrap for the “after” cut.
Before working on the saw, make sure it is disconnected from all power sources. You will be working on the deck of the saw. You definitely don’t want it to activate while you are working there.
Materials
1 Piece of 1/4″ plywood four feet long and about 10″ wide.
1 Piece of 1×3 pine four feet long.
Carpenter’s Glue. I like Tite Bond 3, but any wood glue will do.
Some fasteners for the lumber. I’m using some brad nails and my air nailer.
4 thick pan head screws either 3/4″ or 7/8″ long to attach the fence to the saw. You may find suitable screws just sitting in your toolbox. If possible, use a coarse thread screw.
Construction
Now that you have your materials ready to go, run a 4′ bead of glue down your 1×3 along one of the 3/4″ sides. If you are not familiar with the terminology, it is the 1x side (which is actually 3/4″)
Take your plywood and line up the end flush with the glued 1×3.
Starting at one end, begin to nail the plywood to the 1×3.
Continue to nail down the board taking a moment to make sure the boards remain flush to each other between each nail.
Once the nailing is complete, use a damp cloth to clean up any extra glue that may have seeped out of the seam. This should be done while the glue is still wet. Once it is dry, it is impossible to clean the glue up without sanding it away.
Attach The Fence
Now it is time to get the fence attached to the saw. Mark the middle of the fence at 24″ and place it on the saw. The mark you just made should be under where the blade will make its cut.
Using the pan head screws, attach the auxiliary fence to the main fence from behind the main fence. The main fence should have several holes in it. While holding the auxiliary fence tight to the main fence and deck, drive the screws into through those holes into the auxiliary fence. Make sure the new screws are tight but do not over tighten. They are short screws and can easily tear out the wood, especially if you used a fine thread screw.
Cut the Fence
You are now ready to make your first cut with the new fence. And the first cut will be to the fence itself. Plug your saw in and using all appropriate safety precautions, cut your fence. The first thing you will see is the gap on the deck and fence is now only the width of the kerf. This width is what reduces the tear out. Because it is so narrow, the fence provides extra support to all the wood fibers of the main piece you are cutting. That support is what reduces the tear out.
Take the remaining piece from the “before” scrap cut and make another cut now that the fence is in place. You should notice much less tear out when you compare it to the original test cut.
If you would like to see a video of this fence build, click here. You’ll see how easy this build is!
If you are wondering why your saw’s laser guide is on the wrong side of the blade and not very useful, check out the Laser Guide Video by clicking here.
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