On Jigs and Fixtures

One of the trickiest parts of building a thing with a whole mess of angles is getting everything in the right place. To be honest, the first couple lampshades I built were a bit, well, off. When the edge support needs to connect in exactly the right place at the bottom, it needs to start by being connected in exactly the right spot on the top.

So, I built what I called a jig but it’s technically called a “fixture.” A fixture is designed to simply fix the lamp pieces in place. A “jig” technically not only holds it in place but moves a piece through tool like a saw, where a fixture just holds it.

First, I had to make a block that was the right size to fit inside the crown of the lampshade. This is, again, one of those math problems. The exterior of the crown is 4 1/4″ and, if using 3/4″ thick wood, you end up with an interior of 2 3/4″…

(3/4 + 3/4 = 1 1/2, then subtract 1 1/2 from 4 1/4 = 2 3/4)

Unless of course that particular bit of wood ended up being only half an inch thick, then the interior ends up being 3 1/4″ wide, in which case I need an entirely different fixture to seat properly inside the frame of the lamp shade. So, for now, I’m just making sure I use the same thickness of wood so I don’t have to make different blocks.

Once I cut the block to size, I cut out notches where each of the stays need to go. I set each stay on the crown and traced it onto the block where I knew I wanted it to be, then I measured and found the depth, ran it on the table saw and did a little chiseling. This gives me a block that fits perfectly inside the crown and helps hold all eight stays in the right place.

After gluing and nailing the stays in place, I’m able to pop out the block. Now all the pieces are in the right place and ready for the next step.

Here’s a little video I put together showing a very, very simple fixture in action

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