Monday, March 31, 2014

Original sketches

Here are some assorted drawings of the Zig Zag Chair made by Rietveld. The chair was eventually produced by Metz and Company of Amsterdam.

In the photo below Garard Van De Groenekan, who worked for Rietveld as an apprentice and built many of the Zig Zag chairs, is shown looking at the original chairs in 1987.  

The Zig Zag in white looks pretty nice too!

Saturday, March 8, 2014

More drilling, sanding, and plugging!

Now that the glue has dried, it’s time to sand down the wedges. I left about a 1/16th over on the ends (around 2mm) so sanding these flush shouldn’t take very long.

Here’s the next challenge; the original Cassina version used two rows of dowels drilled internally to provide support to the two 45 degree areas. This is an ideal way to do it (completely hidden from view), but since I don’t have the computer controlled machinery for this, I will do the next best thing.

My plan was to drill the holes through one side of the wood, not completely through, and then to use wood plugs to cover the holes.

I could have done this with a regular drill, but when you do that free hand the drill has a tendency to wander, making the holes not very snug. You can see on this illustration how I planned to make the holes for the dowels used. Two rows used in the main pieces, an additional row that will go through the wedge. This third row of dowels will really help make this a strong joint, since they stabilize the wedge, and go through both pieces against it.

So what I did was set up a support system on the drill press. This took a while to adjust, cut, and get everything just right. The chair now rests against a piece of MDF which holds it at a 90 degree angle to the drill press.

Here you can see how the ½ bit is drilling holes over the wood screw holes used during gluing. Nice and neat!

Drilling is complete, and I know what you’re thinking; “that looks terrible”. Yes, at the moment it looks like the joints are made using swiss cheese, but not for long.

Here’s a shot of the first dowel inserted. Before I glued it in, I slid it in to check the tightness. It was a good fit, but each dowel seemed to be just a hair off. Some too small, the most being a bit tight. So I gently sanded most of them with 80 grit sand paper, and checked each one for fit.  A couple of drops of glue, a few taps with the hammer, and the first one is in. Nice and snug!

A couple hours later and they’re in both sides. No problems yet!

Now it's on to make the plugs to cover the dowel holes. I will use wood from the same area of the main pieces so the color and grain will look similar. I purchased a tapered wood plug cutter. This is used with my drill press to drill the plugs. It’s tapered, so that as I tap the plug in place it will fit nice and snug.

Ready to go!

I let the glue used on the dowels dry overnight, and now it’s time to glue in the plugs.

A little glue, a couple of taps with the hammer, and then wipe each area with a wet rag to get the excess glue off.

The glue has dried on the plugs, so now I can use my zero kerf saw and gently trim the plugs flush.

Next step is to use my random orbital sander to sand the plugs smooth. Now it’s starting to look really good!

Here’s how the plugs look.

When I stain the wood, these areas will blend in well.