Lid design for a cookie jar.

[Sam Fleisher]

Tried searching but all I found was boxes with lids. not how they were made really.

I've never made a lid before, what are some tips or tricks on design/shape.

Do I want the part that sticks into the base tapered or straight edged, how much do you leave for movement? Bowl part is ash with some really subdued colored beads around the middle (see post https://www.aawforum.org/community/threads/what’s-on-your-lathe.20589/post-222951 )and the lid is going to be out of walnut.

Seven inches is the diameter for the opening of the vessel.

I have some small brushed brass knobs that I thought I would mount on the top to pick it up. Just because that's what I have.

 

[Michael Anderson]

Try to match the walls of the insert with the bowl. Straight, tapered, whatever. I imagine you don’t need a tight fit (cookie jar and all), so just make the lid loose-fitting. Your bowl portion is sidegrain, so your fit probably won’t be tight anyway. Thinking about seasonal movement. You could make a sidegrain ash lid though, and probably get a solid fit with equal movement of lid and bowl.

 

[Sam Fleisher]

I didn't have an ash blank platter shape to make a lid but I did have a small walnut bowl blank that fits the bill so that's why it's walnut.

 

[Gerald Lawrence]

Lots of options for this type lid. If you do a recess in bowl rim then the lid jus needs straight sides and you are done.

 

[Dean Center]

The lid would be the same as for any box, except as Michael says, you probably don't want a snug fit. If you haven't made lidded boxes before, Richard Raffan has excellent instructional material. With lids, I think there are two potential pitfalls that you might fall into.

One is the tendency to make the lid too thick and heavy. I would suggest, as best you are able, to shoot for the same thickness as the rest of the container, recognizing that there will be curves and such where this won't be possible.

The other is the "just one more cut will make it perfect" issue. This is accentuated if you follow suggestion #1. When you've got the underside of the lid done, you'll look at the outside and say, "I think I can make that shape a little better." (The woodturning equivalent of "Hold my beer and watch this...") I haven't a fix for this one, but just keep it in mind as you make the lid, otherwise you'll have a nice chocolate colored donut. I certainly have plenty of nice wooden donuts.

 

[Sam Fleisher]

I'm going to try to mimic the shape of the bowl mostly I guess. A flat disc with a rounded edge, little hump to the top. The part sticking down into the bowl was where I was uncertain. I don't want it so loose that it can set off center but I don't know how tight I can go without it locking on with the temp/humidity changes. How much movement will I get with ash/walnut?

And if whoever ends up with it doesn't like my lid, voila! leave it off and you have a bowl.

 

[hockenbery]

I don't want it so loose that it can set off center but I don't know how tight I can go without it locking on with the temp/humidity changes. How much movement will I get with ash/walnut?

A typical cookie jar would be hollowed through the end grain.
These tend to stay closer to round than pieces hollowed through the facegrain
If the top and bottom are from the same blank the wood movement will be similar in the top and bottom

Two basic lid options . A lid that goes into the mouth and one that surrounds the mouth.

A loose fit should not bind if you hollow through the endgrain.
Curved surfaces will tend to settle on better if the grain isn’t lined up.

 

[Charles Cadenhead]

Sam, my FiL made this (he turned several of these for family members). It's end grain with the pith removed and plugged. The lid is loose fitting. The wood is popular with a shellac finish.

 

[Charles Cadenhead]

Dang upload limit....

 

[Isaac Fisher]

If your wood is fully dry to start with you can plan on seasonal movement of about 1/8” per foot of width each year. A little more for some species, a little less for others. Ash and walnut are both pretty much in the middle of the pack.

For a 7 inch opening in a facegrain jar you’ll want a little over 1/16” of slop in the fit. Whether you use the same species of wood or even wood the same tree for the two parts doesn’t matter. If you rotate the lid 90 degrees one piece is moving while the other isn’t. If your fit is too tight the lid will bind, and eventually it will split the mouth of the jar.

For and endgrain jar and lid you can have a closer fit, but there is still a slight difference in movement between the tangential and radial faces. On that size piece you can probably get away with something just a little too loose to be called a snug fit.