Canadian Woodworking

Watch the Edges

-

Melamine, like any material, has its pros and its cons. One of its cons is that it’s prone to chipping when machined and these chips are very noticeable in the finished project. Stack the deck in your favour and use a sharp blade, though that alone is unlikely to solve the chipping problem.

Some of these parts only need a clean edge on one face of the material. An outer gable that will be against a wall will only have its face seen, so any chipping can be positioned facing the wall. For parts like vertical dividers, that’s a trickier situation, as they’re visible from both sides. In this situation I use what I call a “double cut” technique. A scoring blade takes care of this in a production shop setting, but few of us have that luxury at our disposal.

First, a bit of chip formation science. Generally speaking, the underside of a workpiece will chip out as the blade exits the workpiece and damages the lower face. This is in large part because the exit angle of the blade is too close to perpendicu­lar to the lower face of the workpiece. A strange thing happens when the exit angle gets closer to parallel with the underside of the material - it stops chipping. If you make the first pass with the blade set to about 3/16" high, chipping will virtually disappear on the underside of the workpiece. The workpiece can then be re-cut, with the top of the blade above the workpiece. This should drasticall­y reduce chipping, maybe even eliminate it. I’ve also seen people do two half passes with the blade set ever so slightly higher than half the thickness of the material. They flip the workpiece over after the first cut and run the same edge against the fence. Try both approaches and see what works best.

I also like to lightly ease the fresh cut edges of melamine once it’s been machined unless I’m going to apply iron-on tape to the edge. Think of the two sides and one back edge of an adjustable shelf. The edges of melamine can chip easily, unless you ease them. This may leave a very slight gap between mating parts, but it’s much better than medium-sized chips. Easing some of the edges will also greatly reduce cuts on your hands while you work.

?? ?? Clean Edges – After the scoring cut has been made in the workpiece, the freshly cut edges on the underside of the workpiece should be free from chips.
Clean Edges – After the scoring cut has been made in the workpiece, the freshly cut edges on the underside of the workpiece should be free from chips.
?? ?? Double Cutting – If you adjust the blade height so it only cuts about 3/16" into the underside of the material the exit angle of the blade is close to parallel to the underside of the workpiece and is far less likely to cause any chipping. Once the first scoring cut is made you can raise the blade and cut all the way through the workpiece.
Double Cutting – If you adjust the blade height so it only cuts about 3/16" into the underside of the material the exit angle of the blade is close to parallel to the underside of the workpiece and is far less likely to cause any chipping. Once the first scoring cut is made you can raise the blade and cut all the way through the workpiece.
?? ?? Chipped Edges – On the left is the underside of a workpiece that was cut in one pass. Chipping along the underside of the material is very common and will be a problem in any workpiece that’s visible from both sides. The workpiece on the right shows its underside once it’s been double cut.
Chipped Edges – On the left is the underside of a workpiece that was cut in one pass. Chipping along the underside of the material is very common and will be a problem in any workpiece that’s visible from both sides. The workpiece on the right shows its underside once it’s been double cut.

Newspapers in English

Newspapers from Australia