|
The Bad News
One downside of this tablesaw technique is that the panel requires a fair amount of sanding. We’ve developed a solution to simplify the sanding and make it go faster, but if you had to sand more than three or four doors at a time, it’ll get old. However, for one or two doors, the sanding is not a big deal.
The other drawback to this technique, although it’s minor, is that the panel edge is not automatically cut to the right thickness. Because this is the part that fits into the groove in the frame, it has to fit precisely. It’s important to make accurate measurements as you go (Photo 7).
What You Need
Any tablesaw, from benchtop to cabinet saw, can handle this work, as long as you have a sharp, carbide- tipped blade to make the cuts.A blade with a high tooth count (60 or more) will produce a smoother cut than a blade with fewer teeth.And a smoother cut means less time spent sanding.
You’ll need to build a simple auxiliary fence for your tablesaw and a fresh zero-clearance throat plate (see page 50 for how to make one). An inexpensive dial caliper ($15) is handy but not essential for measuring the thickness of your panel edges.
Planning Your Doors
With this method, the panels are cut to fit the frame, so it’s essential to make the frame parts first.You can use a spare rail or stile to test the thickness of the panel edge when it’s near completion.
Glue up your panels, if required,and plane them all to the same thickness. This is important for cutting the tongue of each panel to the correct thickness.
By varying the angle of the fence and the size of the blade you use, you can get an infinite variety of profiles (see page 40).We suggest starting off with a profile that has a small cove on the back of the panel and a larger one on the front. For most door frames, this will make the outside surface of the panel slightly below or flush with the frame,which will make sanding the doors much easier.
For our doors,we planed the panels to 13/16-in. thick, and cut a profile that had a 1/4-in. tongue, a 1/8-in. cove on the back and a 7/16-in. cove on the front.Our maximum depth of cut was 7/16 in.
First, Set Up Your Saw
The actual cutting of the panels is fairly straightforward; you clamp a fence at an angle to the saw blade and pass the panels over the blade, taking shallow cuts. But to get perfect results, you need to set up the fence accurately.We’ve developed a guaranteed system:
1. First,build the auxiliary fence (Photo 3) and make the centering and height boards (opposite page) that you’ll use to set the location of the fence.
2. Find top-dead-center of the blade using the centering board and height board (Photo 1). It’s important that the fence be located over top dead-center so the tongue of the panel is properly shaped to fit the groove in your frames (see Oops!, page 40). This is difficult on many tablesaws because the blade actually swings forward as it is raised. You need to find top-dead-center at the maximum height to which you will be raising the blade, because that height will give you the profile you want.
3. Transfer the location of top-dead-center to your zero-clearance insert (Photo 2).Raise your blade through the zero-clearance insert if you haven’t already.
4. Position the fence on the tablesaw so it covers the front half of the blade,where the teeth point down toward the table (Photo 3). The blade must be down.Use your miter gauge to set the fence at 35 degrees. The edge of the fence must be directly over the intersection of the blade kerf and the top-dead-center line on the insert (below).Clamp the fence securely to the saw, and you’re ready to make a panel.
Cut the Coved Profile
Now that your fence is set, it’s time to actually cut the panels. Here’s the process:
1. Raise the blade 1/16-in. above the surface of the tablesaw and cut the end-grain of the panel (Photo 4). Note that the panel is being pushed “uphill” against the fence. Cut the long grain and repeat the process on the other side of the panel.
2. Increase the height of the blade 1/16 in. and make another pass on all four edges of both faces, end grain first. Now the back of the panel is complete (Photo 5).
3. Finish the front of the panel by continuing to raise the blade 1/16 in. per pass. Use test cuts on the scrap piece to monitor your progress. It will take about six passes to complete the profile on the front.
4. Measure the thickness of the panel tongue (Photo 7). Leave it 1/32-in. thicker than the groove in the frame to allow for sanding. Dial calipers are an accurate and convenient way to take this measurement.
Sand the Profile
To sand the saw scratches out of the profile without spoiling its shape and crisp edges, you need a sanding block that’s made to fit the profile.An easy way to do this is with Bondotype auto-body filler (Photo 8).
When you sand the profile, start with 80-grit sandpaper and move up to 220 grit.When the panel is fully sanded, it should easily slip into the door frame without rattling around inside it.
Tips For Great Coved Panels
Raise the blade in small increments; 1/16 in. at a time. Light passes make these cuts easier on your saw and provide the smoothest surface.
Have on hand an extra panel, of the same dimensions and thickness as your good ones. Use this for test cuts as you machine the panel.
|