A Jar with a Perfectly Fitting Lid

This jar is made on the wheel; thrown as one piece, a hollow form.

After the bottom and diameter are established, the walls are brought up and closed at the top.

This one has a top-knot, but you can make it rounded or add anything you wish after it becomes leather hard.

The walls are purposely thrown a little thicker than usual in order to accommodate the cut for the interlocking lid flange and the base lip. It's also good to make the jar a bit taller, since the lid cutting operation will take some height out of the middle.

This glaze is done with a splotch of green glaze on the bisqued piece, the application of wax resist over that, then the top and base are dipped in a contrasting glaze.

No matter how well matched the lid and base are, there is always the 'perfect seat' of fit. Making a decoration travel from lid to base helps to make sure the lid is returned to this optimum fit.

Below is a diagram I developed to illustrate the technique for cutting lids from closed forms. 

If you click on the image, you can enlarge it for easier reading. With some computers, you can click the curser on the image, hold and drag the image to the desktop, then import it into a document for reference.

If you cut the lid flange at the base of the indentation, it is possible to remove the completed lid and inner flange. Just a bit of smoothing up is needed.

The base, still attached and centered on the batt, can be trimmed on the inside to create a 'shelf' for the lid flange to rest upon.

Unfortunately, I don't have any examples to photograph of the jars I've made using this approach, I've sold them all except for this green one.

It is possible to reverse the cut--make it so that the lid slips down over the bottom flange--by cutting at the top of the indentation to release the lid, then inverting the lid into the base and after securing it, cutting the inner edge, leaving the outer surface undisturbed.

The outer edge of the base may need some cutting adjustment on the inner lip so that the lid slips easily over. This is an example of an early try at the reverse cut.

Once you get the hang of the cutting and a feel for the thicknesses, either way is fine, but I prefer the first method because in my experience, it gives a truer fit.