Snug box lids and wood movement?

[Jesse Tutterrow]

Over the weekend I turned a couple of practice boxes out of scrap mystery wood with snug fitting lids. Snug being not quite a pop fit. Today I go out to the shop and I can't get the lids off. The shop is heated to 70 degrees continually but there is no moisture control.

What do you think is the problem? And more importantly how can I solve it? Or better yet How can I sell a box that has a nice fitting lid today, next month the fit is too loose, and six months from now you need a pry bar to get the lid off?

 

[Richard Coers]

End grain or face grain? Face grain moves more. Moisture content of the wood when you started? Wood has to be pretty old if just air dried, kiln dried is better for tight lids. Snug fitting lids only impress woodturners. The general public expects the lid to come off with one hand if there is a pull. If there isn't a pull, they don't even know what they are looking at.

 

[Roger Wiegand]

Are these end grain or side grain? If the latter, as far as I know there's no solution other than a looser fitting lid. In end grain boxes the lid and box typically move together. I aim for a suction fit and with the woods I normally use (maple, cherry, walnut) don't have any problems as the humidity goes from 20% in the winter to 90% in the summer.

An O-ring or silicone gasket installed on the rim will give you a tight but flexible fit.

Oh yes, and dry wood in either case per the above poster.

 

[Dennis J Gooding]

I agree with the above, but would add that it will help if the the roughed out box is allowed to dry and relax a day or so before final fitting of the lid.

 

[Jesse Tutterrow]

Wood was kiln dried and turned as a spindle turning.

 

[Charlie Knighton]

imo I like mesquite end grain or pear end grain bottom with basswood top.....carve the top and use seasoned wood....i do not do snug but not loose

 

[Jesse Tutterrow]

imo I like mesquite end grain or pear end grain bottom with basswood top.....carve the top and use seasoned wood....i do not do snug but not loose

Do you have any problems with the lid's fit changing? Do you apply finish to the mortise and tenon?

 

[Dan Bevilacqua]

My snug ones get tighter on some days, looser on other days, and perfect on some, depending on the relative humidity, I guess. However, they don't get too tight to the point that I can't get the lid and base disconnected.

By the way, if the lid and base grains are aligned, the fit is better than when not aligned. In other words, on most end grain turned boxes, along the axis, there are two different grain types which I just call the tight grain and the more open grain. In my experience, the movement between the two types differs to some degree. I started a thread related to the grain issues I was having a while back and learned a great deal from those who contributed to the thread.

Another by the way, the book Turning Boxes with Richard Raffan was very informative for me as to lid fitting and of course many other aspects of box making.

 

[Dean Center]

I can't tell you how many times the fit has either gotten looser or tighter after I've made a box with exactly the right fit. Even dry wood can move when the internal stresses are relieved by turning, especially branch or stressed wood. If you get the the effect that Dan describes above, it usually means the wood wasn't completely dry and the wood became oval in drying. I've had this happen many times too. As an impatient person who likes to turn off the waste on the top by using the base as a jam chuck, it took me a very long time to accept the lesson.

The solution, as mentioned here and at length in prior threads, is to turn the top and bottom to a near fit, then set aside and finish turn in a few days.

 

[Mike Johnson]

A little hand sanding is usually sufficient to fine tune the fit of a lidded box when they get stuck. If you go too far you can always put a coat of finish on one of the mating surfaces to build it up to make a tight fit if needed. All woods will expand and contract with relative humidity, but freshly turned items need a few days to equalize their moisture content and natural stresses in the wood need to stabilize.

 

[Owen Lowe]

Wood was kiln dried and turned as a spindle turning.

As others mentioned, allow a few days (to weeks) to stabilize to the ambient humidity, even with kiln dried woods. All woods of any thickness will exhibit a gradient difference in moisture content between the surface and interior. When you cut into it, you are exposing the interior to different environmental MC. Allowing it to "rest" will equalize the MC so that you get a more consistent fit.

Even following the recommendation, I find that all turned boxes will show seasonal variability of fit. I believe this is at least partly due to thickness differences between the tenon and the mortise gaining or losing MC at different rates.

 

[Richard Coers]

Reading all the answers, and had another thought. Diameter of the box will make a big difference as well. I hardly ever make a box over 3" in diameter. Usually smaller. I can't say how many I've sold, but not any complaints about the fit.

 

[robo hippy]

I have made boxes up to about 5 inch diameter, with the 'flutter' type fit. That is using a tenon about 1/2 inch tall, and recess to match. The surfaces must be dead on parallel. I always rough turn and let them sit for a week to a year or three, and never from start to finish on one sitting. If there is any taper to the tenon or recess, this can cause fit problems later on. I do use the same piece of wood for the top as the bottom, and this, most of the time, means the top and bottom will move the same amount for seasonal changes. So, it may go oval, which would mean that you might not be able to spin the top around 360 degrees, but it should still slide off. Other than that, I turn end grain only. Ideal fit to me is to pick the box up by the lid and it takes 2 or 3 seconds for the bottom to drop off. It does take a bit of practice, and a 6 inch metal ruler to place against the tenon and recess so you can eye ball sight against the ways of the lathe to make sure the surfaces are dead on parallel.

robo hippy

 

[Charlie Knighton]

Jesse...bottom has finish....oil....top baby powder...loose fit

 

[Charlie Knighton]

If u have back issues or go into member area look up articles on boxes.....
Linda Gerber has good article on bracelet box......there are many more. Once upon a time I was seated @ same table for din-din @ nc regional symposium with Linda.