35 - Revolving Tool Station, страница 15

TECHNIQUE

Raised Pane\.

Now that the frame is complete, you can add the centerpiece of the door — a solid wood panel with a "raised" field in the center.

The panel is made by edge gluing several narrow pieces. As a rule, I use ³/4"-thick stock and glue up the panel so it's longer and wider than the finished size.

size. An easy way to determine this size is to first dry assemble the frame, see drawing. After measuring the opening in the frame, add the combined depth of the grooves. But don't cut the panel to that size just yet.

wood movement. The thing to keep in mind is that the wood panel is going to expand and contract with changes in humidity.

Most of this movement occurs across the width of the panel (not the length). So I allow for an Vs" clearance on each side (V4" overall). But a V32" clearance at the top and bottom is plenty.

raised field. Once the panel is cut to size, you're ready to "raise" the field in the center, see drawing. It's formed by routing a wide profile along each edge with a raised panel bit, see box.

The idea here is to make a series of successively deeper cuts, see Figs. 4 and 4a. Each pass widens the profile and reduces the thickness of the panel along the edges. By making multiple passes, you can "sneak up" on the final thickness until the panel fits snug (not tight) in the grooves.

To end up with a crisp, clean profile, it's best to rout the ends of the panel first, see Fig. 4. This way, any chipout on the end grain of the panel will be cleaned up when you rout the edges.

assembly. All that's left is to assemble the door. To allow the panel to expand and contract, it's not glued into the frame. Instead, it "floats" inside. So after fitting the panel into the rails, simply glue the frame together. &

No. 35

Raised Panel Bits

An easy way to create a "raised" field in the center of a solid wood panel is with a raised panel bit and a router table.

how they work. The basic idea of a raised panel bit is simple. The panel is held flat against the router table. As you slide it across the table, the cutting edges of the bit sweep across the face of the panel. This forms a wide profile that "raises" the field in the center.

size. It's the width of this profile that explains the large size of these bits. (They can range in size from 2%" to 3V2" in diameter). Because of then-large size, the safest operating speed for the router is 12,000 rpms or less.

ShopNotes

This requires a router with variable speed control. Also, since these bits all have V2ⁿ-dia. shanks, you'll need a router with a V2" collet.

Note: For sources of raised panel bits, refer to page 31.

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NOTE:

rout panel with outside face flat against router table

WOOD MOVEMENT:

WOOD PANEL EXPANDS MORE ACROSS WIDTH THAN LENGTH

raised field

frame

TO DETERMINE WIDTH OF PANEL:

FIRST: measure opening between stiles

SECOND: add the

combined depth of grooves

THIRD: subtract Va" for clearance AT each side (¹/₄" overall)

TO DETERMINE LENGTH OF PANEL:

FIRST: measure opening between rails

SECOND: ADD THE COMBINED DEPTH OF GROOVES

THIRD: SUBTRACT¹/^" FOR CLEARANCE

AT TOP AND BOTTOM ('/is" OVERALL)