Monday, December 13, 2010

Knife


This is probably the best pottery knife I've ever used. I modeled it after several knives produced commercially. It's made from the same rigid smoke color plexiglass as my other tools. I simply cut a long strip of plexiglass, lopped an angle for the blade off the end. Cut the edges sharp on the one side with a bench grinder. The angles funnel the clay away from the pot as it's spinning on the wheel. All of these edges are pretty sharp, but not so much that I would cut myself handling the tool. The plexiglass holds an edge for a while. I used the knife today to cut some old dry clay off a bat, then trimmed a foot in a bowl, and it looks no worse for wear. This simple yet versatile tool has become indispensable in my workshop.

Sunday, December 5, 2010

The Shape of Things to Come


Variety is the spice of life as they say. A good friend of mine is a car enthusiast, and can be found on most any afternoon in his garage working on a project. I often visit him and discuss his projects over a beer and once in a while lend a hand in some small way. A week ago I had asked him if he had any scrap from a plexiglass project he'd been working on. He promptly supplied me with a small piece of a sheet of smoked plexiglass. Here are a few of the resulting tools I made from his generous donation. It's good to have friends with varied interests.

To make the calipers I used a coffee can as a template to start the circle, then I eye balled the change in the curve. I cut the first piece on the band saw and used it to duplicate the part. Once the first set was cut out, I drilled out the hole for the hinge. First try on the drill press I really put the screws to the plexiglass and it cracked and snapped off right around the hole. I lopped the end of the two parts off on the saw and started again with much less pressure.

Once the first set was drilled I assembled it with a small screw, washer and wing nut. The screw was too long so I threaded the wing nut on the screw and clamped it down in the vice. Using a small dremel tool and a cut off wheel I cut the screw down to size. Because the wing nut was in place it pulls the threads on the end of the screw back into alignment, and the screw remains completely usable.

After that it's all lather, rinse, repeat!

The band saw is an invaluable tool for making tools. I would be no where with tool making if it weren't for the band saw, grinder, sander, etc. The dremel tool has a lot of good attachments, and can fill in for a lot of different tools. I haven't found anything that replaces the ease of use of a band saw though.

The ribs were drawn out on the paper that protects the plexiglass, then cut out using the band saw. After that I just took them to a bench grinder and knocked all the edges down. Going slow and using soft even pressure can give a fair edge to a rib. I was in a bit of a hurry on these, and being pressed for time it was required that I run a file over a couple of my edges to remove some chatter from the grinder. This could be left if desired for texture. These were designed to be smooth interior bowl ribs so I knocked the edges down to a smoother state.

Plexiglass acts similarly to wood in some respects. It cuts well, grinds easily, sands quickly, cracks under too much pressure. It's rigid like a wooden tool, but is very smooth, and can be sharpened to a knife edge. So in that respect it has an advantage over wood, which can't get very sharp and dulls very quickly. It's a pretty superior material for making rigid tools. One downside is that it's very slick when wet. I like to use a very large bit to cut finger grips in the surface. I don't cut all the way through, just partially, so there is a concaved mark just under half way through.

Tools

In an effort to have pots more personal to me I have begun to make my own tools instead of purchasing them from the store. I probably don't save any money by doing this once you take into account the time I spend, however I do enjoy the process of making tools. I wanted more than subtle texture, I wanted deep impressions in my pots. I created a tool that in a matter of seconds can make a striking pattern in the clay. The wheel can be interchanged with any number of designs. The possibilities are nearly endless in design of the wheel. Here is an example of the work I did two weeks ago.

This tool took some time to work out the geometry and measure the wheels. I used basic geometry and measuring devices such as a measuring tape and a set of calipers. After deciding on a wheel size, the wheel was measured and cut. I divided the circumference into equal parts and plotted the cuts using the calipers to measure each section. Once plotted I cut the sections out on the saw. Bolting several wheels together I secured them all to my drill press. Using a deck sander I smoothed all the wheels while spinning in the drill press. Taking some of the wheels off and replacing the bolt with just two wheels I used the sander again to shape them as the spin. Once the desired shape was acquired I assembled the tool and made the pot in this picture.

Friday, December 3, 2010

Fuel

I've been doing some research on fuels and kiln patterns for effective fuel usage. A hybrid kiln design is in the planning process. The basic idea is to convert an old electric into a hybrid electric/cross draft. This was the idea that got me started into the research. After reading Dennis Parks book I believe I can have a medium sized test kiln in place by the end of winter.