Monday, January 27, 2014

Having a seat

Here's yet another small challenge in this design; since the seat and back are at 95 degrees instead of 90, it's a little trickier gluing and clamping these two pieces together. You have to apply pressure at the back of the seat towards the front, and from the top of the back to the seat. Maybe pictures will help explain:

 Here is a test fit of the joint. What I have come up with is a bit of a custom glue jig to make the joint stay tight as the glue dries. In the picture above you can see where the back of the seat would need pressure downward to push against the seat, and the seat needs pressure from the back to push from that angle.

Part of the solution you can see above;  I made a piece of wood with several small wood squares glued to it. These squares line up against the finger joints and will place pressure along each finger to tighten the joint.

Here you can see the custom piece I made for the clamp to put pressure from the back of the seat towards the front. It also has small squares that align with the fingers in the seat back.

In the top picture you can see how the block is placing pressure towards the front of the seat, and from the bottom picture you can see the vertical clamp tightening the joint from the top.

 Here's another photo from the back showing all 4 clamps in place.

All in all a tricky glue set up!

And the result.....

Looks good! Nice tight joint, and aligned at 95 degrees!

So far so good, no mistakes (yet)!

Monday, January 6, 2014

Getting a handle on things

So here’s another one of the small challenges in making this chair: the handle on the back. It looks simple, like most of the chair, but in reality it’s a little trickier. Here’s what the handle looks like on the back of the Cassina version:

The plans say it’s 19.5 mm wide, placed 19.5mm down from the top of the seat, and approx. .25in in depth.

I have no doubt Cassina has a high speed routing machine that can cut 1000 of these handles an hour. I’ve never made one like this, so I had to do some research on how to accomplish this.

Here’s the answer I came up with: I’m going to use a .75in cove bit. These bits are used to make ¼ circles in trim molding and other decorative pieces. I ordered the bit, and it is MASSIVE. It’s the size of a small orange, and it’s heavy. I’ve never used a bit anywhere this large before.

I’ve mounted it in the router which is placed on a router lift on the side of my table saw. I turned on the router to make sure everything looked good, and boy did this make me nervous! Even though I’ve set the speed of the router at it’s lowest setting, because of the larger size of the bit, it’s really fast, makes a lot of noise, and produces just a fair amount of wind. Any large, heavy,  razor sharp piece of steel that is spinning at 12000 rpm, scares me.

A lot.

I turned it off, unplugged it, and then made sure the bit was tightened down. Then I checked it again. Then I went and had a piece of cheese, and a soda. Then I came back and checked it again. I could just see this bit coming loose, cutting a hole in my spleen as it went through me, through the wall behind me, through the tree out back, and then coming to rest about 6 miles down the road, leaving a trail of destruction and blood in it’s wake.

But being the confident and secure woodworker that I am, I trusted that it would work fine, although I wish someone else was here to do it, and I could just hide under the covers of my bed.

So I laid out the cut for the handle on the back of the seat.

For controlling the width of the handle, I have set up stops on either side of the fence. All I have to do is place the seat against the fence, slide both directions as the router cuts, and it should work.

I’ve made a small cut on a test piece, it looks good.

Here goes the the real thing…

Not bad! I’m surprised. The cutter easily went through the wood, and made a very sharp precise cut. One obstacle taken care of.

And the best part? No blood loss, no ambulance!