Time for the Left Brain

Hello, and thank you for being here.

We’re deep into Channuka now, so why am I still talking about Seder plates? It turns out that Limmud brought me a custom order for a large Seder plate. I make my own variations, but hadn’t formalized the process with someone else, so I had to set up the work flow to make that possible. The process is pretty simple, actually. We talked about the desires for the design, and I made an electronic mock-up. The customer reviewed the design, and gave approval to proceed. I sent frequent photos showing the work in progress. That is all in order now, the Seder plate has been delivered.

Now, my attention turns to the technical aspects of this — specifically maintain, improving, and calibrating the machine I built.

Here the emphasis switches from smoothness, sanding, and finishing, to bearings, beams, and variables. We move from wood working to engineering — from art to math.

Another Thing that can Go Wrong

Using a unique, home-built high-tech machine has its own challenges. Since I designed every piece, built it myself, loved every joint into place, and wrote every line of code, every failure is my fault. I have caused everything that has gone wrong — and surely there have been plenty of problems. Mercifully, fewer as the machine and software mature, but I am specially responsible.

A few months ago, I eagerly accepted a commission for a customized design, delivered on a tight schedule. It was for a simple customization to one of my large Seder plate designs.

I designed the special variation, the customer reviewed the artwork and gave approval to go ahead.

The customer wanted the design carved in Cherry. I had a piece of Cherry large enough for a large plate, but when I pulled it out to use, I saw a small knot which would be right in the middle.

0.3″ knot in a nice piece of Cherry

The knot was about 1/3″ on one side, and less that 1/4″ on the other. The knot might look really good, or it might be a problem. Since the work was needed quickly, I didn’t want to take that chance.

From my blog entry you may see that I received a large piece of Cherry. It was rough sawn, not planed or sanded smooth. This forced extra steps. First, I modified the tool path to penetrate 1/8″ into the material, deeper than any surface variation. Second, I rough sanded the front so that the surface calibration could find the real surface, rather than the rough original surface.Wood clamped and smoothed

I set up my machine, loaded the design, and set it to cutting. It was looking good, so I came inside to see my wife for a few minutes. Later, I went out and saw an unexpected bump in what should have been a flat region.
A Z-axis discontinuity, caused by the wood cracking and shifting. I assumed that something had gone wrong with the machine, or with the constantly changing software, and the Z-position had been compromised. My heart sank as I anticipated debugging my system, hardware or software, quickly enough to meet the customer’s need.

Looking closer, I saw that the wood had an open a crack from the end. The crack had split and shifted the wood, and that shift had caused the problem.Cracked from one end of the wood deep into the plate.

I chalked up the problem to unseen stresses in the wood that were concentrated as the thickness was reduced. I prepared the next position on the plank, clamped it more tightly with better support, and cut it without incident.

That bit of wood became firewood.

Wood is a natural material. Each piece is unique, and it is always challenging. Finding the right wood is hard, but knowing how any particular piece of wood will respond is, for me, nearly impossible. As an engineer, I like to anticipate problems. As an artist, I accept that materials have their own, inscrutable behavior.

Wow! What a Day.

Thank you, everyone came by to talk and see my work today at Limmud Boston, 2012.

Special thanks to those who liked something well enough to make it theirs.

Talking with you all today made me itchy to bring the store up to the level of my work. I’ll be completely redoing the store, and items will be appearing shortly.

Again, thank you for a wonderful day.

Opening hour at Limmud

I’m set up, and ready to rock. So many people to talk with.

The day is here, everything is set up. If you are in Boston, consider coming to Limmud. The conference is in full swing, with activities throughout the day. Walk in registrations are welcome. And, when you come, stop by and say hello.