Jig Process

A classic example of the jig-making thought process.

SHOP OWNER: Jim Shaver
LOCATION: Oakville, Ontario, CANADA
[EDITOR'S NOTE: Although Jim's idea for this jig proved successful, it did not work for the intended job.]

    This is a series of pictures of a jig I built today to use on my compound miter saw to support angled rip cuts. I have been working on a set of Morris chairs and I have been tossing several ideas back and forth as to how to make a bent arm. I looked at several methods and narrowed them down to three.
    The first method I looked at involved cross cutting the arm stock at 3 and using biscuits to attach the long grain to long grain joint. My test arm worked, the joint was surprisingly strong, supporting my 240 lb. weight. However, I was not crazy about the glue line.
    Another choice involved one of Stickley's methods. I could resaw a wedge off the bottom of the arm and glue the wedge back under the arm. A perfect grain match and an invisible glue line were some of the benefits and, of course, the continuous grain on the top of the arm.
Jig Process

    This design became my focus, but how do I cut this? I thought my way through a sliding jig on the table saw, but it would require an inversion of the part after the initial cut, since the arms are 5 wide. It did not sound simple enough.
    I next thought about the band saw; lay out a line and cut... okay, perhaps... but what else? I wanted perfect angle control of the cut... maybe the compound miter saw?
    Okay, so I thought, how do I support the type of cut I was after on a compound miter saw, and came up with this jig. I have a 12 Delta with a Forrest WWI blade.
Jig Process

    For what it is worth, it took me 30 minutes to make, a squared piece of plywood and some scraps of oak.
    I used a simple arch in the jig fence to support the blade guard as the saw descends; it rides out on the curve and controls the guard.
Jig Process

    I liked the design. It worked well on thin stock, but as I found out with a test piece, it only worked up to 4 wide stock because the guard on the fence stopped the blade descending completely through the cut. I could either remove the blade guard or cut the groove deeper into the fence. I tried a few cuts with the guard removed, but I put it back on. I need to work out some details and maintain the guard.
    While making sample cuts, I supported the work with a hand clamp against the outboard edge of the fence, and used another clamp to support the face of the jig against the compound miter saw fence as well as the hold down.
Jig Process

    I liked the idea of the jig but, in the end, passed on it for my wider stock. I set up this piece to show how I intended it to work.
Jig Process

     I cut the arms tonight on the band saw and glued the re-sawn wedges under the arms to create the bent look.
Jig Process

    In the end, I have carefully worked my bent arm design and techniques through a series of processes. I built a jig for one of those processes, which despite not using it, it will support other work in the future.

. . . Jim Shaver



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