Half Laps

w With half laps, you can w do more than just build a simple frame. For both the lamp and the serving tray in this issue, we used half laps to create a grid. To do this, a series of half laps are cut along the center of the workpieces so they cross over each other.

To do this, the tools are the same as with end laps, but the dado has to match the width of the laps (or you have to make more than one pass, see next page). And the procedure is a little different too.

For one thing, laying out and cutting the laps accurately on each intersecting piece would be a hassle. But fortunately, there's an easier way. Instead of working with individual workpieces, I cut the half laps in extra-wide blanks (wide enough for two or three pieces), see Fig. 8. After the half laps are cut in the blanks, the pieces will be ripped to final width.

Note: If there's a frame that surrounds the grid, you can cut these pieces to finished width and cut the end laps on them first, see the photo above and page 13.

When the blanks are planed and sanded to final thickness, the next step is to lay out the half laps. Because I use a stop block when cutting the laps, I only lay them out on one of the long blanks. And I like to draw the layout lines on the face opposite the laps. Then I draw reference lines for the notch on the auxiliary fence, see Fig. 7. This way, to set the stop block, I simply align the layout lines between the reference lines on the fence.

Another good layout tip is to mark an "X" to indicate where the half laps are to be cut, refer to Fig. 8. Otherwise, you could accidentally cut one of the laps in the wrong place.

With the half laps laid out, the next step is to cut them. To do this, I use the rip fence as a stop. You can set the fence for each lap, or if the layout is symmetrical, you can make two passes with each setting, flipping the piece end-for-end. (This will cut the number of setups in half.)

Note: If the half laps are wider than the dado blade, you'll need to make more than one pass, see next page.

After the laps are cut, the blanks can be ripped into individual pieces, see Fig. 9. But before doing this, it's

a good idea to mark one end of each blank. This way when it's time to assemble the grid, you can make sure the pieces are oriented the same.

When ripping the blanks, the key is to size the individual pieces so they fit snug in the half laps, see Fig. 9a. You can use a test piece to do this or rip your first workpiece a hair wide and sneak up on its final width.

When all the pieces have been cut to size, the last thing to do is assemble the grid. To do this, I typically dry assemble the grid to test the fit of the pieces. Shop Tip: To check that the assembly is square, use a framing square. Then to glue the grid together, I remove one piece at a time and add a drop of glue to each lap.

After the pieces are glued in place, I keep the assembly flat by setting a piece of plywood and some weight on top, refer to photo on page 8.

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Wood Working for Amateur Craftsman

Wood Working for Amateur Craftsman

THIS book is one of the series of Handbooks on industrial subjects being published by the Popular Mechanics Company. Like Popular Mechanics Magazine, and like the other books in this series, it is written so you can understand it. The purpose of Popular Mechanics Handbooks is to supply a growing demand for high-class, up-to-date and accurate text-books, suitable for home study as well as for class use, on all mechanical subjects. The textand illustrations, in each instance, have been prepared expressly for this series by well known experts, and revised by the editor of Popular Mechanics.

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  • SOINTU
    How to cut styrofoam half laps?
    2 years ago

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