Tandem Slides and Drawer Dimensions

      To notch, or not? Cabinetmakers discuss the fine points of matching slide specs to drawer sizes. August 29, 2005

I've been using the tandem slide with a dovetail drawer for a couple years now and have always notched the front and the back of the drawer. Recently however, I realized that there is no need to notch the front of the drawer. For the 550 slide I always make my boxes 21 1/4 deep and I assume without notching the front I just add the 5/8" size of the front for a total of 21 7/8? I'm just trying to figure out why two years ago that my rep told me to notch the front of the box. Do most people just notch the back of the drawer box?

Forum Responses
(Cabinetmaking Forum)
From contributor J:
Which Delta dust collector did you have? I have a 1 1/2 hp run through 4" sewer pipoe in the attic with three tees going to different machines and it doesn't have quite what Id like as far as taking all the dust. You can hear the suction at the other machines even when the little plastic dividers are shut.

From contributor B:
I don't notch the back, the back is cut 3/4" shorter and the bottom is glued/stapled.

From contributor S:
I use tandem slides exclusively. I use 1/2" drawer side material. I make my drawers 21" deep, 1/2" recess, and notch and drill the back only.

From the original questioner:
You make the box 21"? It seems like it would be too small when you use the 550mm slide and only notch the back. Can anyone else tell me how deep their drawer box is for this size slide?

From contributor I:
To the original questioner: Make sure that you read the specs clearly. Some of the posts make their drawers 5/8 and some 1/2. There is a difference, 1/4". Get the technical specifics from your hopefully replaced rep.

From contributor H:
Every box of tandem slides comes with a clear instruction guide for all lengths. The cabinet depth, slide-length and total drawer length are clearly listed. We build our drawers from melamine or plywood with a butt joint and the front and back shorter by 1/2" plus the thickness of the bottom (usually 5/8").

It is easy to calculate cutting sizes this way. For an 18" drawer the bottom and sides are 18". The back front and bottom of drawer are the same width. The bottom of the drawer is pinned with a 2" 18 guage brad into the front and back and pocket-holed into the sides. I often stand in these drawers to show clients how strong they are, and I weigh 175 pounds.

From the original questioner:
I've gone through a couple hundred boxes of tandems and have yet to see a set of instructions. Also, with a 1/2" vs. 5/8" box, wouldn't the front to back, outside dimension of the box only be a difference of 1/8" if you are only notching the back of the box? The extra 1/8" would come from the extra thickness at the front.

From contributor S:
To the original questioner: If you can't get your hands on a set of the instructions, the orange technical sheets that Blum has for each piece of hardware they sell should be available from your distributor or from the Blum website. The instructions are very clear. I always use 1/2" drawer sides and the drawer box is always 12", 15", 18" or 21" total depth. It's what the specifications call for, and it has always worked.

From contributor H:
To contributor S: I have only used 5/8 melamine for my boxes and have never had a problem with the sides rubbing. I install my slides in the 5mm holes with euro screws which have a flat head that goes flush with the track. Any supplier worth his salt should be able to supply you with a Blum manual or you can get it from Blum.

I have never opened a box of Tandem slides that didnt have the instruction sheet inside, and that is from Canada and the US. The lengths that Contributor S mentioned are constant, although I know one shop that sets the slide into the box a little and makes a longer drawer. He say's that his clients like the extra depth. You just have to set the orange locking device in the front back to allow for this difference and you must use a solid bottom as you cannot screw the device into the front of the drawer.

From the original questioner:
To calculate the size of a box, you take the size of the slide (in this case I'm working with the 550mm slide) then subtract 10mm (that gets me to 540mm, which is 21 1/4). Then add for the thickness of the front (which I use 5/8" ). That gives me a total of 21 7/8". I did a test drawer and it worked perfectly. If you use 1/2" material it would total 21 3/4". I got this out of the Blum manual. I'm still confused as to how your numbers work out for you.

From contributor R:
To the original questioner: What do you mean 550mm slide? What is the Blum part number? 562H5330B is for 21" drawer. The drawer box lengths are always 12", 15" 18", 21", 24", 27" and 30."

From the original questioner:
The drawer slide I use in a 24" deep cabinet is the 560H5500. The drawer slide I use in a 21" deep cabinet is the 560H4500.

From the original questioner:
I just took a look at Blum's website and looked up the tandem slides. In one of the photographs you can see the underside of the dovetailed box and the front is notched. Why would they be notching the front?

From contributor S:
To the original questioner: I had another look at the Blum website and I couldn't find the photo showing a notch at the front. Anyway, you don't need a notch at the front, only the back. You screw the orange fixing bracket to the front lip. If you notch that away there would be nothing to screw to.

I did see a lot of specifications calling out what the front to back overall drawer size should be, did you catch that? It doesn't have anything to do with doing math. It really does spell out what length drawer should be used with what drawer slide.

From contributor R:
To the original questioner: Blum sells 560H series slides in Europe, and you are correct for front notch.

From the original questioner:
I'm actually in Canada and according to two of the suppliers here, they sell a lot of the 560H in Canada. I wonder why I'm getting something different then what it seems like the majority of you guys are getting?

From contributor S:
To the original questioner: If I remember correctly, you can do either one, notch the front and screw the orange fixing bracket straight down, (up), to the drawer box front, or set the fixing bracket on the drawer bottom right in the corner made by the drawer box side and front, and angle the two wood screws into the drawer box front. It does seem like the drawer box would need to be shallower front to back than 21" if notching the front, though. By the way, the Blum part I use is a 562.

From contributor R:
For a five piece drawer (this means a four sided drawer box with a drawer front applied to the front of the drawer box) that is used in overlay construction, a notched front is required. If the front is not notched, the drawer box will need to be longer (by the thickness of the box front). If the drawer is longer, the drawer will not be true full extension.

If the drawer is a four piece drawer, (the drawer front is the front of the drawer box, usually a sliding dovetail joint) a notch is not necessary (there is nothing to notch). The above is in regards to the slides available in Canada. The reason the notching is required is because these slides are originally meant for four sided boxes used in inset construction.

From contributor H:
I have just moved to Florida from Montreal, Canada. The slides are the same. There are different number codes for the heavier duty tandem slides which are just a thicker steel profile. The drawer dimensions are the same for both models. If you mount the track on the carcass with the 37mm 5mm hole the track comes to within a couple of mm's of the front of the cabinet.

With a drawer box that has a front and back, you must notch in the front and back or make the front and back shallower than the sides and use a 5/8" bottom to mount the front clips to. If you dont notch the front, then it will stick out of the cabinet side by the dimension of the front (5/8 or 1/2 depending on your construction techniques).

From the original questioner:
I don't see how the slides can be the same. For the 560H5500, the drawer box is made 21 1/4 deep and that's with the front notched. Others here are saying they make their boxes 21" deep and don't notch the front. I've tried it and there is no way that size box will work with the 560H5500.

From contributor B:
To the original questioner: Are you using the standard locking device or the inset locking device on those tandems? We use 1/2 material and make our overall drawers the nominal length of the slide- 21", 18", 15", and have never had a problem.

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