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Nov 28, 2017

How to Prevent Tearout and Splintering When Cutting Plywood, Once and For All

Plywood is awesome. It's affordable, easy to work, and, when used properly, looks great. 

Plywood also brings its share of headaches, specifically, tearout: the rough, jagged edges that result from cutting through the thin veneers. It's frustrating, and it looks absolutely terrible. Any woodworker who's ever used it can speak its woes, which can ruin an otherwise high-quality project.

But my friends, it doesn't have to be that way. Whether you're building a simple shop project or a full fleet of custom kitchen cabinets, you, too, can virtually eliminate tearout.

Let's make some crosscuts.        

 

What is tearout?

Tearout happens when you cut across the grain. Here, the fibers aren't supported by those next to them, so, when they take an impact, they naturally flex themselves. This gets them out of the way, taking your nice clean edge with them. 

So, to get rid of tearout, we need to adjust two things in that equation: how well the fibers are supported, or, how intense the impact to the fibers are. We'll do both in the steps below. 

 

First things first: Choose the right blade. Choose the right face. 

Naturally, you'll want to select a fine tooth blade that works well to cut plywood. These tend to have more teeth per inch, as well a higher bevel angle that can slice through the wood. For a circular saw, you can easily pick up a plywood blade for $15 at any home center, and it will work magic on your cuts. On the table saw, you might not need an expensive specialty blade, though they can help. Just make sure you're using a high-quality combination blade with at least forty tooth blade.

Secondly, you want to cut the wood so that blade enters the wood on the show face. For a circ saw, this means placing the good side down, and on a table saw, the good side up. 

 

Always use a zero-clearance insert.

No matter what tool you're using, the best way to reduce tearout is to surround the blade or bit with a zero-clearance surface. This is equally important on the band saw, drill press, miter saw, or table saw. A zero-clearance insert creates the smallest amount of open area around the blade to support the wood fibers surrounding the cut as much as possible. Hopefully, you've dealt with this in your shop, but if you're still using the stock throat plate, it's time to make or purchase an upgrade. 

 

Score the cut line first.

Tearout looks so shaggy because the top and bottom veneer get snapped off in unpredictable ways when they take an impact. So, one way to prevent the rough edges is to intentionally cut the fibers where you can control them. They're going to snap somewhere, so you might as well tell them where to do so. 

 

You can cut across the graid with a straight edge and sharp blade, or if your cut is close enough to an edge, a marking gauge makes quick work of this step. You can even cut your parts oversized, score, then go back and make your final cut to size.

Since you can only score one side of the kerf, make sure you set up your cut so that the "good" side sits at the intended side of the blade. 

 

Support the wood fibers around the cut with tape.

Since tearout occurs when the fibers get pushed in all directions, you can help these stay in place by placing painter's tape over the cut line.

 

I've had a lot of success with this method on simple shop projects, jigs, etc, so its worth the extra couple of seconds and the cost of the tape whenever you're cross-cutting plywood. I keep a roll of blue tape on my table saw cart so I never have to decide whether its worth it or not. 

 

Make Two Passes on the Table Saw

Whenever you're making furniture quality cuts, or perhaps you're working with melamine or some large panels, tackle the cut in a two-step process. Many cabinet shops even have table saws with two blades, one for scoring and one for through-cutting. This does the exact same thing, but you just take a full pass for each cut.

To make the initial scoring cut across the bottom of the wood, set your blade about 1/16" above the table, and make a complete pass. 

Here, there's not a lot of downward pressure from the blade, so it doesn't impact  the fibers as much, and leaves a nice, clean surface. (If you're setting your alignment with a fence or stop-block, you could even hack this system by first making a scoring cut on the show face, then flipping it to make your final cut.) 

 

Next, raise the blade to the appropriate height to cut to size. By creating this scoring relief cut, you're reducing the impact to the fibers, keeping them where they belong.

 

Each of these methods work, so try them with a scrap of your particular sheet of plywood and tool/blade setup to see which gives you the best results. You'll end up using each idea, or a combination, for different approaches, so commit them to memory, and save the frustration for another part of the project. 

 

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Jim on Oct 25, 2018:

Great Instructions! Had never seen them before.


frank barker on Oct 21, 2018:

Thank You for the information. Being a beginner, anything I can read and try, that I think may be a help to me to me, I read and try.

This tip you have provided will be of great help to me. Again I thank you


Colin Bluett on Oct 17, 2018:

I am working with MDF at the moment and I find the sacrificial piece (at the point where tear out occurs), seems to be the best way to save the work material. Drilling holes in MDF was a real problem with breakout until I placed some scrap underneath. Thanks for supplying several alternatives to try.


Melvin Bray on Oct 15, 2018:

Bravo! Your right on the money with this post. I have used both methods myself with great success. I tend to use the tape method the most along with the proper blade and have not had any bad cuts yet. Thanks for the info, Mel


Erin on Oct 13, 2018:

This a really great post. So helpful. Thank you!


Grammar Nazi on Oct 01, 2018:

Your. YOUR. "If you're alignment is set with a fence or..."


Chris on Oct 01, 2018:

Hey Daed - You're welcome to ask for clarification any time. I totally welcome questions. I think that'd be more helpful for everyone than just being critical of what I have or haven't done.

I define what a zero-clearance insert is in the post above: "No matter what tool you're using, the best way to reduce tearout is to surround the blade or bit with a zero-clearance surface....A zero-clearance insert creates the smallest amount of open area around the blade to support the wood fibers surrounding the cut as much as possible."

Regarding using the appropriate terms: I don't think they're particularly technical at all. In fact, if you're using a table saw - a very dangerous power tool - I think it's essential to understand your machine. You should read the manual that came with it, and understand the parts before making cuts on any table saw. But, for clarity - a throat plate is the removable piece that came with your saw that surrounds the blade. It's probably steel or aluminum. It likely has a large slot that the blade peeks through, and its wide so you can tilt the blade for angled cuts. A zero clearance insert replaces the stock throat plate, providing more support around the blade.

Next time, just ask :)


Daed on Sep 21, 2018:

You're using technical terms that the recreational builder doesn't understand.. ie. 'zero clearance cut', and 'stock throat plate,' etc.. people reading this article are not gonna be pro's.. please try to dumb down the article for us recreational builders.


Mike on Aug 15, 2018:

Great tips. I use tape routinely, but haven't thought of scoring the wood first.


Colin on Mar 10, 2018:

I found this information particularly helpful. Using Tape alone does not seem to work for me. Sandwiching the material with a sacrificial piece is another good idea, this way the tear-out side actually has support to prevent the chipping.