I started making these little thrown round boxes a few years ago. They are made to be fired in a specific place in the kiln. Place them against the back of the arch on the top shelf. There they catch a lot of ash that falls on them as the flame dumps it as it curves downward. A lot of them go into the kiln with out any glaze on them. This one has my Thistle slip glaze on it.
A make the pot with 1.5 lbs of clay. After pulling up the walls I indent the top 1/2 inch using a wooden tool and carefully measure the out side of that indented part.
The lid is thrown from 1 lb of clay. I throw the inside to the same dimension as the outside of the indentation on the pot.
When the lid and pot are a firm leather hard and of equal moisture content I make a pad of clay I can use to press the pieces against as I trim them.
Next I trim the bottom of the pot in the same way.
Now I center the pot on the trimming pad and anchor it in place with four wads of moist clay.
The lid is usually a little small. THat is better that loose. With the moisture content equal I can carefully trim to fit. I get the moisture content more or less equal by covering the pots for at least 24 hours after the initial drying to the leather hard state to allow the moisture content to equalize.
Using the square edge of a rib I carefully trim away the clay a little at a time, checking often to find the right fit, until it is just right to accept the lid.
With gentle pressure on the top I then trim the lid to make the profile of the two parts continuous.
Here is a tool I use to make a variation on the texturing. It is simply a textured roulette that I turn on a piece of heavy gauge wire as the finished pot turns on the wheel.
Good Luck and Happy Potting.