Routing Openings in Solid MDF Doors

Tips on using a CNC machine to rout openings for glass in solid MDF. March 1, 2006

I have to make several MDF doors with glass and mullions. I'm wondering how you would remove the material on the back side to accept a single sheet of glass. My main concern is locating the door properly, so that it is centered. I have a theory. If I cut a "mask" out of 1/4" MDF for each size door and then create a tool path to clear the entire area where I want the glass, that should get me centered. If there is a better way, please advise.

Forum Responses
(CNC Forum)
From contributor R:
I use 1/4" dowels inserted into spoilboard to align things like that. From 0,0 I'd move the gantry to -.125(x) and drill 2-3 holes along y, and repeat it for the x axis. I recently cut a run of poker table parts out of 60" x 60" birch ply. I only have a 48" x 96" table. I used dowels to register the parts and turn them 90 degrees.

From contributor M:
If you use a T-slot bit after you rout the center panel, you'll be able to make a "glass lip" without removing your door and realigning it. Just remove the center panel after you rout it and come from the side, i.e. arc lead-in, and cut the inner perimeter of the door with T bit. I used to make all kinds of different shapes with glass inserts this way. Only disadvantage is it leaves large radius in corners on the back side where glass is inserted, but if you know this, then you cut glass to fit the panel or remove excess material from corners. It worked fine for me.

From contributor N:
This was one of the problems we answered in our program. Now we apply geometry to both sides of a nested sheet of MDF doors and simply run the bottom side of the sheet first, flip the sheet and run the top.