Getting the warp out is a very long shot at best. I'm sorry to be the bearer of bad news, But I work with warpage on old furniture weekly and there are a few tricks to get rid of the warpage, but they are "out there" and often times the results are not worth the effort. On top of that, doors are the worse :-)

The good news is that if it's not bad, often times a catch will work as well as any repair to the door itself. It just depends on the severity of the warpage.

Here is a link that might be useful: lawless hardware

Some catches have enough force to flatten warped doors when they are closed.

It can take a couple catches instead of a single one, and the closing and opening force is then increased.

It can be a good trade though for a door not used on a daily basis.

Thanks for the responses. The section that is warped is up at the ceiling so it would not be practical to have a catch up there. I was wondering whether anyone every uses anything like steam with clamps to "encourage" the door to relax. Or any other thoughts? Thanks again . . .

Not gonna happen. The amount of heat and moisture that it takes to soften the lingin enough to do that sort of reshaping would destroy the door. Besides which, any force you apply to the door risks breaking some leaded glass. Give up now on the idea of un-warping it.

Perhaps a hinge could be repositioned to help hide the problem? You could also have a new frame built and transfer over the glass, but it would probably be a very expensive door.

It always helps to post pics so we all know what we're talking about.

Sayde,
We have tried it all. Having been in the restoration bussiness for a long time, you have a tendency to come across these situations from time to time...lol You can search around and find people and articles that will tell you what you want to hear, but for most cases it's not practical and won't give the desired results. I understand it's not what you want to hear, but jon and I are dealing you the truth.
Adjusting/ moving hinges and adding catches are the #1 most effective method. If you choore to use heated moisture, it must be applied to the exterior side (concave) only...so you will need to strip the door of it's finish and sand before steaming. It then must be clamped for a week or two. Then...most likely, it will just spring back either right away or within time.

The reverse of that repair is a better option to try. That is to attempt extracting the moisture from the wood from the convex side. Again, no finish can be present on the wood. Use a hot (dry) iron on the back of the door and then clamp. Be careful, but you must heat the wood to the point of extracting all moisture.
A hot plate works better if you have a larger one. I have a large griddle in my kitchen I have used. Again...be careful not to overheat the wood.

Your last and most invasive option is to cut grooves with a router and glue in battons and clamp up on a perfectly flat surface (I use a large piece of 1" thick marble on my workbench).

Obviously, the glass needs to be removed for any of these options to be explored...or you could try the catch and hinge adjustment and be done. If you can refinish the door, you can shave it down with a wood plane until it's flush.

Good luck!

Umm what side is convex?? OK, OK I'm getting a dictionary, never mind.

Could you tell me more about the "invasive" method - what size router bit, how deep, how far apart, do the grooves go lengthwise via the grain or across grain. I have some warped table top parts I want to get flat and then glue together - and then hopefully once I attach to the table apron/legs it will stay flat, I could even glue some oak plywood underneath - it won't show since its under the table.

"I have some warped table top parts I want to get flat and then glue together"

Just rip them into narrower strips and then glue them back together.

A trip across a jointer for each strip (or some hand planning) to square up the cut surfaces to the top and bottom is what really flattens warped wood.

Thank you for all the responses. I guess we are going to just live with it and accept it as one more old house eccentricity. But it greatly helps to know that we didn't overlook any opportunities. I will look into the catch that was recommended.

Thanks again!

Kashka Kat,

Table tops can be straightened, but a table saw works better in that application. There are so many variables, every job is unique. I never go into a job such as yours with my mind set on any one way to accomplish the repair. I don't mean to be vague, just being real. Plywood will bend with the warped top in most cases. Besides, it's probably a solid wood top because it's warped, right? Solid tops need to have the ability to expand and contract, so glueing and screwing the top to plywood could be bad news down the road :-)
Warpage is a tough problem to beat unless you have a good deal of woodworking knowledge. Even so, it's a tough fix sometimes. Tops are easiest though...so that's good news for you! We'd really need to see pictures of the table to be of any help.

I realize this is an old thread, but someone may find the info useable.

I recently bought a used cedar hope chest to refinish for my daughter. Unfortunately, I left it on the porch through hurricane season and it became warped. The right front corner of the top was about 1/8" - 1/4" too high and the top of the right side separated from the front at the corner about 1/16". So, I did what most people do when they have questions. I googled it. Planing and grooving were out of the question for me. Even clamping and steaming seemed too much. Although the cedar chest was dry, I guessed the rain had gotten to it, so I probably needed to remove the moisture. I have a double work lamp with halogen lights that gets very hot within a few feet. I put some weights on each end of the chest, set the lamp up and pointed it to the right front side. I used a blow dryer on a couple of small areas on the left side and moved the weights to different spots before going to bed. I left both lights on and opened the chest the 2nd day. The 3rd day, I split a toothpick and used it and wood glue as filler for the small separation left at the corner of the front and side. I also used the wood glue for other small cracks. I closed the chest, put the weights back on top and began sanding in about four hours. I began painting the next day. Now, my daughter has a beautiful hope chest.

Also, here's a link that may help:

http://m.wikihow.com/Unwarp-Wood