I’m planning to build an office desk to my own design. I want to make a glass window in the desktop. What would be the most aesthetically pleasing way to mount glass to the wooden top so they would together form a flat surface (small space between glass and wood is fine as long as they are on the same level, and so there would be no bumps).
I think glue doesn’t cut it. It wouldn’t look good also I just don’t like glued things, I prefer when things are nicely screwed together…
Use a router to cut a rabbet the same thickness of the glass. Drop class in to rabbeted hole. Nice and flat.
You want to be able to lift the glass panel out of the insert to clean it. Otherwise you will end up with dust and crumbs around the edges making it hard to clean and it will look like hell. Do not glue it in!
**Sicks Ate **is right. I would cut the desired size hole in the desk, router out an edge of the hole to a depth, probably about 3/8 inches for a this panel of glass, for the glass to lay into, leaving a ledge that the glass will sit in, and just drop the glass in. You can then just push the glass out from below, clean the area, and put the glass back in. This is how my last glass/wood coffee table was built. This assumes you are putting the glass panel into a level desk.
I would go to a glass shop and order a piece of tempered glass to fit the hole you have created. Tempered glass is much stronger than regular glass and if it breaks it will turn into little corn sized chunks that wont send anyone to the hospital. Most glass you see used in desks or tables is temp glass.
With tempered glass you have it order it to the exact size that you want, it cannot be cut after it is tempered or it will also turn into little corn sized nuggets.
So build your desk panel first, measure for the glass, order glass, drop in. That is the way I would do it.
I’m thinking you get a piece of glass with a very long, shallow bevel and cut the hole in the wood desk top with a complementary bevel, like a scarf joint (fig. iii). Mount the glass from underneath so it’s flush on top, and secure below the desk top with rails. Smooth, clean look from the top, and you can only see how it’s put together from the bottom.
So not mounting it at all? Wouldn’t it “rattle” inside the hole?
nail it down should do the trick.
a rabbet is the way. you could either cut it into the desktop or affix the same uniform around the whole edge support by attaching wood to the bottom of the desktop. attaching some wood from below may take lots of wood and glue to be near as sturdy as a routed rabbet, you have to decide based on the material involved.
you will need thick tempered glass, at least that of a glass table top.
Use a couple of small self-adhesive foam-rubber “dots” and stick them to the rabbet. The glass will sit on them and the rubber will keep it from shifting around, including keeping it from rattling when you press down on the glass.
I’d go for a very thin smear of silicone sealant along the supporting rim of the rebate - let it cure before dropping in the glass.
I’m using a glass above timber table at the moment. It doesn’t wobble.
8mm (1/4 ") weights enough to hold it in place on the varnished surface… the varnish tends to squash down … lots of stick. It won’t move until one end is prized up and air is let in.
All good suggestions and I appreciate your desire to prevent the glass from rattling once it’s placed into the routed opening in the desktop without using an adhesive. My approach would be to use thin strips of wood placed on each side of the glass.
Route the opening as described above but make the support rabbit about 1/4" larger than the glass leaving a 1/4" gap on all 4 sides once the glass is in place. At that point, insert your 1/4" wood strips into each side of the glass (I’d also miter the corners of the strips) that with some sanding and planing, will give a snug fit to prevent any glass movement and keep out debris as well.
I would modify Sick Ates suggestion slightly. The rabbet idea is sound and what I would do. You want to be able to remove the glass for cleaning, replacement in case of breakage, etc.
Quarter inch thick glass has a fair bit of heft, rattling and rolling shouldn’t be much of an issue. If it is, then your desk top has bigger problems 
My modification to Sick Ates suggestion is the additional step of being sure to rabbet with a bottom cutting bit and leaving a bit of meat on the rabbet for you to sand/plane/file/ it smooth. You will be able to see the wood through the glass and a regular router bit (heck, even a bottom cutting router bit cutting too deep in one pass) can leave a mess, especially on cross-grain routes. Buy the right bit, sneak up on your final line and sand smooth.
Also, if the glass is square at the corners, you’ll need a good sharp chisel, as a router can’t cut square internal corners.
