wpe73.jpg (12176 bytes)

   With the success last week of using the Incra Jig to make dovetails and box joints, I wanted to try my hand at making a joint that really can only be made with this type of a system. Incra calls it the Incra Cornerpost Eagletail—it's the one used in the jewelry chest in the pic and I really like its look.
   The project book from Incra is so clear in its instructions, that I decided to make this chest to get familiar with making the joint. Now after having made 2 such jewelry chests (3 if you count the one that I goofed up) , I can honestly say that learning by making this chest makes total sense.
   So in this site, my neighbor Bethany will go through the step-by-step with minimal guidance from me.

   The project book is the "Incra Jig Projects & Techniques" book written by Perry McDaniel. Just like the Incra instructions, it is very well written and superbly illustrated. While it helps to be familiar with the basic Incra Jig setup steps...as I discussed in the dovetail and box joint section, one can use this book as the sole source. It covers techniques of Incra joinery as well as it presents 13 projects. Anyone who has now or is considering getting the Incra Jig should have this project book. That said, on on to the project...

wpe74.jpg (19312 bytes)
wpe75.jpg (14791 bytes)

   The first task with any joint is to select the stock and router bit. The project book specifies the exact dovetail bit and gives dimensions for each piece.

   Bethany sets the router depth from the book's "approximate  router depth" setting.

wpe76.jpg (15991 bytes)
wpe77.jpg (11833 bytes)

  She is using the Incra Measuring Gauge that boasts accuracy to .004". It is ideal for setting bit height as here and a number of other shop operations. Once the approximately height is set, she uses the depth setting procedure detailed in the dovetail section.

   The following is from the dovetail making instructions. This next step is kind of tricky. Its purpose is to set the absolute correct depth of cut. You start by aligning the fence over the bit so that 1/2 the bit is exposed. At that point you slide the correct template so that an "A" mark is under the line. You make the cut at this "0" position. Then you move the fence to the next "A" point at make another cut. You make this cut on two boards clamped together.

wpe86.jpg (17004 bytes)
wpe87.jpg (10599 bytes)

Then you flip one board over and put the two together. If they fit perfectly, your router depth is set exactly right.
  
Now back to Bethany and her project.

   Having cut an approximate center position in one scrap board from both directions, she can now sight the bit to the exact center. This procedure is basic to all Incra Jig operations and one that is quickly mastered.

wpe7A.jpg (15200 bytes)
wpe7B.jpg (10545 bytes)

   She uses the micrometer adjustment to visually center the trial cut to the bit. Once centered she can lock the center point.

   With the center point locked, she can install the correct template and line the zero point to the cursor line. This centering operation is essential for the rest of the milling operations. Both the router bit height adjustment and the centering procedures are easy to do. Take your time and follow the written instructions exactly.

wpe7C.jpg (19518 bytes)
wpe7D.jpg (13345 bytes)

  She is almost ready to start cutting the pieces. The first task is to stack the ends and sides vertically in the right angle fixture. We used a wood clamp when we did the original joints; this time we are using a quick release clamp. Whatever you use, be sure that the pieces are secure in the fixture. Note also that a backer board in included.

   There are three nylon screws on the right angle fixture. The center one is used to lock the fixture. This is useful when clamping the boards in the fixture. The outside two screws are for adjusting the amount of lateral tension on the slide. It is important for the fixture to slide smoothly but not wobble. There are lock nuts that should be tightened once the proper fit is determined. The fixture must be adjusted properly to keep the cutting operation in tight tolerance.

wpe7E.jpg (16237 bytes)
wpe81.jpg (19126 bytes)

    Now Bethany can start cutting. The book tells her exactly what cuts should be made. She adjusts the fence so that the right position is under the cursor; locks the clamp; and makes the cut.

   The cutting of both ends takes just a minute.

wpe80.jpg (15490 bytes)

Main Menu -- and now available in  PDF File

Next Page

Go to Mfr.'s Site