Glass in a cabinet door

Wood changes very very little along it's length.  Therefore, if your door frame is built like a common picture frame, i.e Stiles and rails, with long grain parallel to the edges of the glass you should not have any issues with wood movement.  You want the glass to easily fit into the opening, so make the opening an 1/8-3/16" minimum larger than the piece of glass.

Thanks it is a shaker style door frame made from soft maple.

Thanks

I made some glass doors with the framing being hardwood about 1-1/2 to 2" wide. Lee's recommendation on size is good. In my case, the doors were not for fine furniture but for built-in, painted display cabinets. It's been a while so I'm not certain but I think my glass was about 1/8 thick, not the the thinnest available. If the glass panel is large be careful of going too thick - glass is very heavy and you may need to be concerned with hinge loading.
You also want to ensure the glass is secure year around - nothing more annoying than glass panels rattling when the door is opened or closed.
Glass expands or contracts very little so, even though I've never used them, if you follow the Spaceballs recommendation about compressing I would think they would work but they will need compressing to hold the glass. Since I wasn't making fine furniture, I just made a rabbet for the glass and then applied a very small bead of clear silicone to hold it. Not elegant but worked well and the glass can be easily replaced if damaged.

Mike L wrote:

I know wood moves with humidity.  I am making a door with a glass insert.  So I have two questions.
1 how thick of glass should I use?  The routered grove is 1/4 inch
2 how much smaller then the opening should I get it cut?

I will get there with the help of y'all

Presumably you're describing a relatively small cabinet door using material about 1-3/4" wide by maybe 3/4-1" thick. Ignore the dimensional change caused by humidity variations because the parts are too small for it to matter. Glass thickness should be between 3/16" - 1/4" depending on the door size and its purpose. Glass dimensions should also be about 1/8" smaller than the opening. In some circumstances it may be an idea to consider toughened or laminated glass. Importantly, replace the groove you plan t use with a rebate and beading screwed/pinned in place to hold the glass. The loose bead allows you to replace a broken piece of glass, which a groove doesn't. You could, alternatively, putty the glass in place if that's visually appropriate, or belt and braces, putty and a loose bead. Slainte.

Thanks. I am going place it in a rebate I planed to use the glass points used to hold single pain windows in, then place a small piece of wood trim around it, in case it needed to be replaced.  The first ones I am doing are small pieces of glass on the top of the door maybe 12 1/2 by 9 or so.  The next ones will be full glass doors.  

How thick is the door? You say that the groove is 1/4" I assume that the 1/4" is in the plane of the door, but how deep? I would make the routed section 3/8" deep. That would allow for a piece of glass that is 1/10" to 1/8" inch thick and a 1/4" square wooden strip to retain the glass. I precut the 4 pieces of 1/4" strips that retain the glass and sometimes even miter the mating ends of the square strips. I insert the glass and wooden strips into the door and hold them in place with brads. I have a hand held tool that, when squeezed,  sets the brads. By using the hand held squeeze tool I do not have to swing a hammer so close to the glass.

@rlipeles.  The door frame is 3/4 thick by 1 3/4 wide.  The grove is a 1/4 wide in the center of the width 1/2 inch deep.  I cut one side off the groove so now it is 1/2 in depth.    I have one of those tools you squeeze and it will set a brad, it was my fathers.  I will have to figure out if it works.  I also have a small pin nailer I can use.  

Thanks

Bed the corners of your glass with a dab of silicone chalk to eliminate rattling between the glass and frame. You may want to consider using "safety" glass that breaks into small crystals rather than sharp shards in the event of an accident.

I'll add another strong recommendation to use tempered glass. I believe building codes require it in doors for safety reasons as Dave pointed out.

Don't miter the corners of your wood beading around the perimeter of your glass. A miter makes it very hard to remove the beading if you have to replace a pane of glass.

@JR. Um it is too late.  I mitered all the corners.  I am just going to use caulk to install them, no pins or brads.  Unless the beading needs it.  Stay tuned

Mike L wrote:

 I am just going to use caulk to install them, no pins or brads.  Unless the beading needs it.  Stay tuned

It does. Use small screws if possible rather than pins or brads. Slainte.

These days I always use screws if the retainers are mitered.  Small brass screws look fine - slotted rather than phillips.  I've worked with ones that are brad nailed, you can get away with that if the brads aren't too close to the miters.  Usually you don't care about the glass if you're pulling those out (glass already broken) so you can pry against it and bend the brads as you slide the retainer up.  Screws do just make things easy though.