Blum Tandems questions

[Sam Murdoch]

I am about to build a pair of drawer boxes. These will be 4 piece - no added front - the front will be the finished face. Sides, fronts and backs will be connected to each other with sliding dovetails. These drawers will be mounted on Blum Tandems. The face of the drawer will flush with the face of the finished board - in this case a stair riser. I will take the 2 fronts from the same board/riser so my clearance/saw kerf will be the smallest I can maintain - hopefully no more than 3/32". I intend that all top edges will be flush to each other.

My questions are about the Blum spec that indicates I need a 1/4" minimum clearance from the top of the drawer box to the top of the frame. Is this for adjustability? I would like to maintain a 3/32" reveal from the top of my drawer face to the flush "rail" above. Do I need that 1/4" that Blum says? Will I need to cut the sides of the drawer boxes down? There is way more room than 1/4" behind the face of the drawer front.

Anyone with experience ignoring that particular Blum specification? Thanks.

[Chris Padilla]

The 1/4" is there for adjustments after the fact. The slides themselves have an adjustment to move the drawer up/down or top/bottom. I think you'll be fine with the 3/32".

[Jay Jolliffe]

Have you thought about the 5/16 you need for the side clearance....

[Peter Quinn]

I don't think its a major issue, as long as you are above 1/8" clearance. I've never understood why they allow so much at the top. The drawer fronts at work always have far less than 1/8" reveal's, though the boxes are lower, applied fronts being used. I can't imagine they would rub. I'm working on a set of boxes now that will ride on tandems, sliding dovetails all around, I made the sides stop lower for design reasons, slid the sides into the dovetails, glued a strip on the bottom to cover the dovetails slots.

[Dave Zellers]

Boy is this timely for me. I'm days away from trying something very similar- no false front, inset, regular dovetails on all four corners and hoping for 1/16 to 3/32" gap all around.

I don't see why the top gap would be a problem since these slides just move in a straight line front to back. I'm planning on dealing with the side gap by installing the drawers in the carcass (these are kitchen base units with all drawers) before the face trim and then rabbiting the face trim to cover the thickness of the slide side leaving the smaller gap.

But all I've done so far is the mental work from looking at the Blum specs, I'd love to hear, along with Sam, from anyone who has done this.

Sam, you could just allow for the setback on the sides when you cut your drawer faces out of the riser.

[Sam Murdoch]

Have you thought about the 5/16 you need for the side clearance....

Yup - That won't be an issue -the clearance on the side is for the drawer box (3/16" each side for 5/8" thick drawer sides) and my front will overlay the drawer sides to the correct reveal as the front will be ahead of the slide. That's what you are suggesting Dave, right?

As for the top clearance I wondered if it might be needed to set the drawer box onto the slides - though I don't see how that might be. I'm just wondering out loud here since I don't have any samples in my house to check. This has never been an issue. Drawers built like this I usually hang on side mounts or within their own box, which is why I'm asking in this case.

[Dave Zellers]

my front will overlay the drawer sides to the correct reveal as the front will be ahead of the slide. That's what you are suggesting Dave, right?
That should absolutely work in your case. My drawer front will be flush with the drawer side (blind mortise) so I plan on closing the side gap by pulling the face frame over an eighth or so past the inside of the carcass. Since the front of the slide extends past the carcass halfway into the face frame, I'll rabbit around that. Seems like it should work. In your situation, it sounds like you will be blocking out the sides inside the framing of the stairs for the slides so you have flexibility there to shim for perfect alignment.

[Sam Murdoch]

Looking forward to our next posts Dave. Sometime next week I'd guess...

You've got to understand the rules to break them :)

[Terry Therneau]

I'm just finishing up a cabinet with drawers similar to your description, using a drawer-lock bit rather than a sliding dovetail. I found that it helped to relieve the drawer box a bit, so mine drop down 1/2" in an S curve about 1" back of the face. (1/4" would have been enough, I drew a curve that looked pleasing to me). I found that I had to sand just a bit of relief in that 1" as well: getting the drawer face fitted nicely is one thing, making the whole drawer maintain 1/16 from the top during the entire travel was another. I also wondered about that "min gap" in the instructions and thought I'd give it a try.

Terry T

[Sam Murdoch]

I'm just finishing up a cabinet with drawers similar to your description, using a drawer-lock bit rather than a sliding dovetail. I found that it helped to relieve the drawer box a bit, so mine drop down 1/2" in an S curve about 1" back of the face. (1/4" would have been enough, I drew a curve that looked pleasing to me). I found that I had to sand just a bit of relief in that 1" as well: getting the drawer face fitted nicely is one thing, making the whole drawer maintain 1/16 from the top during the entire travel was another. I also wondered about that "min gap" in the instructions and thought I'd give it a try.
Terry T

This seem sensible to me.

[Steve Baumgartner]

I've done a bunch of Blum tandem slides. The only reason I can imagine that they specify such large clearance is so that the drawers don't bind even if you run the adjusters all the way to their max. But even that doesn't really need 1/4 inch. I've gotten away with much tighter fits with no problems.