I am building a large custom desk/cabinetry project. First, there is a row of lower cabinets across an entire wall. Then there is a 5" thick desktop (it's hollow in the middle, but it looks like a whole forest of trees went into it). The desktop extends a foot deeper than the lower cabinets so that a chair can roll under it and there is space for the user's knees.
This desk calls for two 20" deep drawers underneath the desktop. There were a few big changes of design throughout the project, and I let the 20" drawers slip past my guard without thinking about hardware. The cabinets are only 24" deep, so even with 24" full extension runners, the drawers extend 24" - 12" = 1 foot past the edge of the desktop. It's actually even less with the drawer fronts. Unfortunately, almost everything is built already, and I can't really relocate the drawers. If I can't figure out a solution, I'm just going to make false fronts and scrap the drawers altogether.
So what I need is not only full-extension, but over-extension runners. The only such monster I've found online is made by a company called Chambrelan. Has anyone dealt with their products before? They appear to offer 150% over-extension runners made with four beams. So my drawer could pull out 36" with just a 24" deep cabinet. I haven't contacted them for prices yet, but I imagine they will be outrageous.
Has anyone run into this problem before? I thought of using two pairs of slides (mounted together via wooden blocks) per drawer, but I have serious doubts about both appearance and performance. The other idea was to make custom slides using two/three brass-plated rods per side and a whole bunch of linear pillow bearings (believe it or not, I happen to have such bearings lying around already, but not any brass rods).
Would it be possible to attach two slides with some tack welds? I too would be nervous about the wooden blocks, but a local welder could probably weld a couple together pretty cheaply.
That way, when the drawer is out, the 12" slide is closed (so the wood runner sticks out by 12") and the 20" slide is open. When the drawer is in, the 12" slide is open (so the wood runner is inside the cabinet) and the 20" slide is closed. The torques will therefore be reasonable. The only drawback I can see is that I will have to disable the Blumatic self-closing feature of my slides, and install a magnetic latch.
The drawers are wood - maple interior with red oak fronts. I am planning on going with wooden runners, as was suggested. The main slides (which hook to the drawer) will be undermounts, and the smaller 12" slides will be side-mounts. It looks like I'll lose less than an inch per side (width-wise), plus the regular restrictions of any undermount slide.
Thanks to all who posted.