Trust me; I’ve been there. You’re in the garage, building a bookcase out of plywood. Fueled by iced coffee and feeling empowered by the sharp roar of the table saw, making all the neighbors wish you’d just move already. You tap the off switch, ready to admire the beginnings of what will soon house your collection of random tchotchkes and 3-ish books.
But what do you see when you take a gander at your handiwork? None other than an ugly, splintered plywood edge along your entire cut.
Fighting the urge to flip over your expensive table saw like a woodworking Theresa Guidice, you need to find a way to stop your plywood from splintering before wasting any more exorbitantly-priced wood.
We’ve all experienced the same issue at some time or another, and over the next few paragraphs, I’m going to give you a plethora of tips and tricks to help you escape it.
What Causes Splintering?
Have you ever seen someone try with all their might and fail to tear a large phonebook in half versus the ease with which they can tear out a single page? Well, cutting plywood is a bit like that. Plywood is made by gluing and stacking layer upon layer of very thin sheets of wood veneer into one solid panel of wood. This stacking and gluing make plywood very strong as a whole unit, but each individual sheet of veneer is actually a very fragile element.
Now imagine using a table saw to cut through that same phonebook. It stands to reason that the pages with the greatest support or compression, like the pages located mid-way through the phonebook, would be sheared through cleanly. The pages without much surrounding support, like the book covers and maybe some of the A’s and Z’s, would probably have rough, uneven edges. But why is that?
Simply put: the act of cutting through wood with a saw of any kind is a forceful thing, and when the top-most or bottom-most veneer fibers take on that force, they not only are taking on the brunt of the force, but they also aren’t as supported as the innermost veneers and are less able to withstand that force. As a result, the thin wood fibers within the surface veneers can fray, tear, and break along the cut-line.
Knowing the causes of splintering, how can we spare our projects (and our wallets) from this very annoying and common issue. The way I see it, we have three options:
- Increase support for the veneer fibers on the surface of our plywood;
- Reduce the force the fibers have to deal with in the first place; or
- Be super proactive and combine different methods to achieve both things!
Some of the possible solutions we will explore below are specific to either a circular saw or a table saw, and some are more general. When possible, try combining methods to give you the best possible shot at getting a clean cut.
How to Stop Plywood from Splintering?
General Methods (Not Tool-Specific)
- Cut parallel to the grain rather than across the grain, if possible.
This will lessen the amount of “cross-cutting” being done to each tiny wood fiber along the cut-line, thereby limiting how much extra support they need.
- Apply painter’s tape along your intended cut-line.
Taping your plywood before cutting will add extra support to the wood fibers along the cut and lessen the amount of force being applied to each individual fiber. The tape will handle the brunt of the saw’s force.
- Use a cutting gauge, a razor blade, or an Exacto knife to pre-score your cut-line before cutting, either on both sides or on the “good” side of the plywood.
These tools make a thinner, sharper score-line along the wood fibers, thus decreasing the amount of support needed when cutting since the important part of shearing the fibers has already been done.
- If you can cut more than one sheet at a time, face the “good” sides towards each other, then clamp or tape the sheets together and make your cut.
Each of the inner sides will add support along the cut-line to the other, thereby preventing splintering on each.
- A blade with more teeth will cut much more cleanly than a blade with fewer teeth, even if they are both the same size blade.
- When using a 7 ¼-inch blade, aim for a 60-tooth or higher blade.
- For a 10-inch blade, aim for an 80-tooth or higher blade.
- And for a 12-inch blade, aim for 100 teeth or higher on your blade when possible.
- See how to select a circular saw blade..
This method can be applied when using virtually any type of saw with a circular saw blade and is similar to pre-scoring. Make the first cut with your saw a very shallow cut, only letting the blade reach about ¼ to ⅓ of the way into your sheet. Then make the cut a second time with the blade set to cut the full thickness of the plywood sheet.
Now, let’s see the tips to avoid tearout when using specific power saws. The handheld circular saw and table saw are the most commonly used tools for cross-cutting and ripping large sheets of wood, plywood and MDF. A jigsaw or a bandsaw works best for cutting shapes on wood.
Cutting Plywood with Circular Saw
Here are 3 ways to avoid splitting plywood when cutting with a handheld circular saw.
1. Good Side Down
When using a circular saw and holding it as if you are about to make a cut, you’ll likely notice that the teeth on your blade point upwards, and the blade will generally spin clockwise. This means that the first contact with a tooth of the blade will occur at the bottom of the piece you are cutting.
This also means that the blade will exit the plywood at the top of your board, increasing the likelihood of tearout or splintering on the upward-facing surface. Therefore, you want the “good” side of your plywood facing down because:
- the fact that your sheet is facing downwards means that support is being added by the surface you are using to hold your plywood when making your cut, and
- the tearout, if any, would occur at the top of the piece being cut rather than the bottom.
2. Zero Clearance Base
Try adding ¼-inch hardboard to match your circular saw shoe. Retract your blade and attach it with double-sided tape. When you run the saw and lower it, cutting through the hardboard, you will create a zero-clearance opening for the blade. This will increase the support to wood fibers along your cut-line and minimize splintering.
3. Use a Circular Saw Edge Guide (or Track Saw)
A track saw is arguably the best bet for cutting plywood cleanly, but they aren’t quite as common or portable as everyone’s favorite job-site-handy circular saw. So if you don’t happen to have one lying around, the next best thing is an edge guide for your circular saw, whether store-bought or DIY-made. This will minimize side-to-side motion as you cut along your plywood, maintain the support of the wood fibers along the cut-line, and keep your cuts straighter! As Michael Scott would say, it’s a win-win-win.
Cutting Plywood on Table Saw
A table saw is another common power tool that is often used for sizing plywood. While most of the general tips apply here, there are a couple of things you need to do differently on a table saw.
Good Side Up
When using a table saw, you’ll notice that the teeth on your blade point downwards, and the blade will generally spin counter-clockwise. This means that the first contact with a tooth of the blade will occur at the top of the piece you are cutting.
This also means that the blade will exit the plywood at the bottom of your board, and if you don’t have a zero-clearance insert installed, the fibers along this line will be largely unsupported, which can increase the odds of chipping or tearout on the downward-facing surface.
Therefore, you want the “good” side of your plywood facing up because the tearout, if any, would occur at the bottom of the piece being cut rather than at the top.
Use a Zero-clearance Insert for Your Table Saw.
Get a precisely machined zero-clearance insert from the machine manufacturer. This will ensure that your cut line is fully supported underneath. Doing this in conjunction with facing your plywood up can help ensure that both sides of your plywood are “good” sides.
If you don’t have a zero-clearance insert for your table saw, you can achieve the same thing by making your own table saw sled with a zero clearance cut.
Make sure your sheet of plywood is fully supported on all sides when running it through your table saw. Pulling and dropping it to one side or another while cutting or shifting it from side to side can not only interfere with a straight cut, but it can also make the cut splintered.
Get the help of another person, or set up saw horses, rollers, or other support surfaces to make sure your large plywood sheet is fully supported throughout the entire length of your cut.
Using JigSaw to Cut Plywood
When using a JigSaw, aside from the fact that you may not be aiming for a straight cut, there can also be quite a bit of side-to-side motion that doesn’t exist when using a table saw or circular saw with a track. This motion can increase the likelihood of splintering along your cut-line.
Though this is not the best tool for the job when making straight cuts, you may find yourself still needing to use a JigSaw to cut a profile with straight line and curve through plywood, or maybe you need to make curved or rounded cuts which this tool is perfect for, and in these instances, using painter’s tape along your intended cut-line is your best bet.
Try using these methods the next time you need a clean cut!
- What Causes Splintering?
- How to Stop Plywood from Splintering?
- Cutting Plywood with Circular Saw
- Cutting Plywood on Table Saw
- Using JigSaw to Cut Plywood