When cross-cutting a plywood panel,
the bottom layer of veneer often splinters out along the cut line. But there
are steps you can take to prevent this.
Perhaps the easiest way to avoid splintering is to use a blade that's made just
for cutting plywood. These blades have lots of teeth (typically 80), and the
teeth are ground in a pattern that creates a clean, shearing cut.
But what if you don't want to spend the money for a single purpose, rarely used
saw blade? There are a few tricks you can use to get a clean cut with a
combination blade.
First, if the blade is crusted with sawdust or pitch, clean it before cutting
the plywood. Sometimes, however, even a clean blade will splinter the veneer.
There are two reasons for this. One is that a combination blade has fewer teeth
than a plywood-cutting blade, so it doesn't cut as cleanly.
The other reason is that the cutting edge of the teeth may be pushing the
veneer down rather than slicing it off.
One way to avoid this is to change the cutting angle of the teeth by raising or
lowering the blade. If your panel is splintering on the bottom, lower the
blade. If it's splintering on the top, raise the blade.
The most common way to get a clean cut is to score the panel along the cut line
before making the cut. To do this, cut through the veneer layer with a sharp
utility knife.
While this method works, it's sometimes difficult to line up the saw blade with
the scored line. An easier way is to score the panel is to use the saw blade
itself. The idea is to make the cut in two passes. On the first pass, set the
blade just high enough to cut through the veneer layer. Then raise the blade to
finish the cut on the second pass.
Another way to keep the veneer from splintering on the bottom is to use a
backer board. This is a piece of plywood or Masonite that's placed below the
workpiece when making the cut. This way the veneer layer is fully supported and
the plywood can be cleanly cut.
Follow-Up Comments from reader that originally appeared with
Tip #38:
Last week, I mentioned several ways to cut plywood cleanly on a table saw.
Several members of this group wrote to suggest another good technique that I
left off the list: covering the cut line with masking tape or 1" wide
clear cellophane tape.
The idea is that the tape holds the wood fibers in place so they don't splinter
out during the cut. They're right, this works well.
The reason I didn't mention it is that you have to remove the tape after making
the cut. And if you've ever had the TAPE pull off a splinter or two (as I
have), you'll understand why I'm not so enthusiastic about this technique.
I think the important lesson here is that if you use this tape technique,
remove the tape immediately after making the cut.
Go to Tip #38 |
