Blum Tandem Slides

http://www.blum.com/us/en/11/02/index.php
Will give all the information you need. Its hard to say from you description above what you are exactly saying?
Are you putting 4 drawers into a space that is 13 and 1/2” tall? I would just do wood side mounts and be done. Little drawers like that will have nothing left with under mount glides.

-- Bob www.bobkloes.com

Their info doesn’t quite answer my questions, or I can’t find it in the several pages I have looked through.

Particularly the drawer bottom thickness and the height of the side mounting plate.

You are right on the 4 drawers in a 13 3/4” opening. I’m aware its a small space, and most people would just put some side mounts and be done. The drawers will be used for measuring tools, chisels, pencils and random small tools. I think it will be fine to have the top drawer only an inch or so deep. I have spared no expense in making it all solid wood and no screws or nails for the structure, so I’m willing to work around the Tandems if it means I will feel better about it when its done.

Get the ones plus Blumotion. My entire kitchen has them. Best you can get.

-- "Of all the things I have lost in life, I miss my mind the most."

The Blum Tandem undermounts require a 1/2 inch recessed bottom in the drawer. The thickness of the drawer bottom can be whatever you want. Blum Tandems have a couple different models in the same LENGTH depending on the thickness of your drawer SIDES. The tandem also requires 9/16 clearance at the bottom. So with 9/16 clearance AND a 1/2 inch recess, you’ve already lost 1-1/16 PLUS you lose the thickness of the drawer bottom. Using a 1/2 inch drawer bottom, your 1 inch deep drawer will use 1 + 1/2 +1/2 + 9/16 or 2-9/16 of vertical space. There’s also a bit of clearance required ABOVE the top of the drawer side so you can lift the drawer to remove it and put it back in. So a drawer with 1 inch of usable interior height is using right around 2-3/4 inches of vertical space.

This isn’t peculiar to the Blum tandem. Most undermounts have these same requirements. You could FIT 4 drawers in that space. Like 2 at 2 and a half inches and 2 at 3 inches… something like that. It would be tight and you’re wasting 4×1-1/16 or 4-1/4 inches just to the recess and bottom clearance.

In this particular case I think the side mounts would give you far more usable space.

I used 32 pair in our kitchen and love them. It’s hard not to slam non soft close drawers now. People think your mad about something.
But I would not use them in the space your talking about. For the minimal amount of weight your talking about, I would make hardwood side runners.
Btw I used 1/4” for my bottoms.

Soft close in a side mount drawer runner is disappointing. You are not wrong. I used some for a project in my kitchen and I ended up taking out the mechanism with a pair of crocodile pliers..
Soft close is nice, but do you really need it in a workbench?
If it’s all made of wood, I’d go with a grooved drawer side and beech/hardwood runner. You’ll end up with bigger drawers and this arrangement is surprisingly strong (I use mine as the Deadman all the time without issue).
If you are dead set on soft close undermount, check out the ones made by GRASS. They are adjustable in every plane, front/back, side/side, height front/height back. They cost less than the Blums as well (from Häfele).

-- Do or do not, there is no try

I thought about wood runners, but if I’m going to use the drawers a bunch, I want the drawers to function smoothly for many years to come. I wish it wasn’t so dang hard to get the undermounts out of my head now, whether or not this is the best application