I have some 35 year old kitchen cabinets that have the single roller on each side and the runner down the middle. they have worn and are grumbling. There is approximately a 1/2" space under the bottom of the drawer and the bottoms are 1/4" plywood.
Has anyone converted these drawers to the runners that fit under the drawer? What runners did you use? Anyone tried laying 1/2" full extension rails down flat?
I have used Grass Dynapro Guilds. If you don't have 5/8" Drawer side you need to hold the Guilds out from the side 1/8" on the bottom on each side and cut a notch
If you can get the old fronts off, and want to reuse them, I'd just make new drawer boxes. The quick and easiest method, is to just use 1/2" baltic birch, cutting the fronts and back 2" less than the opening width, and the sides however long your slides are, or depth of cabinet.
Glue and staple those together, then staple a 1/4" bottom on with staples on about 2" spacing. The slides cover the edge of the bottom, so nothing shows on the sides.
This isn't fine woodworking, but it isn't trash either, just quick and efficient. When it comes to shooting the bottoms on, by the end of a big run, my trigger finger is about as fast as a bumpstock as I drag it along the edge firing the staples in. This makes a very strong box that can't be undone. You would destroy all the parts trying to bang them apart.
I built some drawers for my pantry using full extension soft close under mount slides. This is the one I used. This vendor has a large selection. Click on the catalog button.
I just bought some 10" side mount full extension rails for less than $4 a pair. They are not soft close, but they are not $20 or more either. What am I missing? Are people really paying $30 for 40 a pair for runners?