another Blum undermount slide question

[charlie kapper]

Did I mention in my last post that this was the first time I (attempted) to install Blum undermounts. Well not going to good so far. Anyway, did all the math for the drawer box size, built the drawer and the cursing began. Actually, I am not sure if I got the drawer width correct. The opening in the cabinet face frame is 13 7/16". How much total (inches or fraction of inches - no metric please) should I subtract from the opening for the final outside to outside drawer width dimension? The drawer I built is 12 15/16 and does not work. Once you figure the final drawer box width, how much tolerance is there. I am using Blum 563H drawer slides and 1/2 " Baltic Birch for the drawer box material. I have been all over the Blum web site ( and many others) and thought I got what was being recommended but unfortunately something is wrong. At least I didn't build the other three drawers. I have a kitchen full of drawers to build soon and really need to get this right. Any other helpful hints would be appreciated. Charlie

[Brett Bobo]

Hi Charlie,
Using the 563H's with 1/2" BB material for the drawer sides, the out to out measurement of the drawer box should be approximately 12 3/4". Reference actual page number 13 of the following pdf file:

http://www.blum.com/pdf/BUS/1100_tdm_563_b/1100_tdm_563_b.pdf

Additionally, measure the actual thickness of the BB material you're using for the drawer width measurements, even though the nominal dimension is 1/2".

Hope that helps.

[charlie kapper]

Thanks for the reply Brett... So do you think the 12 15/16 drawer that I built is too wide?

[Erik Christensen]

from the blum pdf:

NOTE: Material thickness may vary. Inside drawer width must equal opening width minus 42 for TANDEM to align and run properly.

Calculating outside drawer width
For drawer side thickness 16 (5/8") 15 (19/32") 14 (9/16") 13 (1/2") 12 (15/32")
Deduct from inside cabinet width 10 (13/32") 12 (15/32") 14 (9/16") 16 (5/8") 18 (23/32")
Example: For 21" opening width and a 5/8" thick drawer, 21" minus 13/32" = 20-19/32" drawer width

SO if your drawer side material is actually 1/2" then you have the correct drawer width - one mistake I have made is order the wrong slides - check your slides for the part # - trying to make a 1/2" drawer work with 3/4" slides and visa-versa does not turn out well

[Brett Bobo]

Charlie,
Yeah, it appears you're ~1/8" too wide on your box if the out to out box width should be 12 13/16" based on 1/2" material. I'm assuming that's what you're finding, correct? If available, use a digital caliper to determine the actual thickness of your material and adjust accordingly per the chart. Just for future reference, a few passes with a hand plane with solid wood boxes would salvage your box and you'd be back in business. Depending on the joinery of your box, there may still be simple fixes. Of course, once you dial in the width with a trial run like this and get the kinks out, the remainder should go smoothly.

[David Hawxhurst]

maybe math is off but i come up with a max draw with of 11 13/16".

opening is 13 7/16"
space required by blum 13/16" x 2 =26/16" or 1 10/16" so
13 7/16 - 1 10/16 = 11 13/16"

[Mark Bolton]

maybe math is off but i come up with a max draw with of 11 13/16".

opening is 13 7/16"
space required by blum 13/16" x 2 =26/16" or 1 10/16" so
13 7/16 - 1 10/16 = 11 13/16"

Correct, to the inside o the box. Add his side thickness (1/2") and you have 12 13/16 outside width. He is 12 15/16.

[David Hawxhurst]

maybe i'm just understanding the blum drawing correctly. to me it looks like you take the opening then subtract the the space needed on each side which should give you the max final outer dimension of the drawer.

good thing i'm not building the drawer cause i would have made the outside dimension to 11 13/16" wide giving me 11 1/8" inside dimension using 1/2"(15/32") plywood based on the opening being 13 7/16".

[Jeff Duncan]

Brett has it close, his box is too wide. I'm looking at an older catalog for the 562's but I believe the dimension stayed the same. For a 1/2" box side you deduct 5/8" from the opening width giving you a box size of 12-13/16" wide. FWIW you don't really need dial calipers, a tape is plenty accurate enough to measure the side thickness. There is a fair amount of play in the slides....probably 1/16" or so. But if your off an eighth I believe your making a new box. It's always good to start out with a mock-up when trying out new hardware as sometimes it's tricky to get it right the first shot. I've made hundreds and hundreds of boxes using the tandems and I still double check myself to make sure I'm dong them right.

It's also good to double check your hardware. I use 3/4" solid maple boxes and ran into trouble on my last kitchen job. One set of drawers went in normally and worked great but the next set wouldn't work right! I double checked all my dimensions and seemed like everything was right. It took a little while but I finally discovered that 2 of the boxes of slides I got from my supplier were the wrong ones! I got the slides for 1/2" boxes instead of the 3/4" versions!

good luck,
JeffD

[Sam Murdoch]

Brett has it close, his box is too wide. I got the slides for 1/2" boxes instead of the 3/4" versions!

good luck,
JeffD

Jeff is right that Brett's box is too wide but in the interest of clarity may I add -

The Blum tandem slides whether the 552s, 562s, or 568s do come in versions for 3/4" max thickness drawer box sides (from 3/4" down to 23/32" and 21/32") and versions for drawer box sides of a 5/8" maximum thickness (from 5/8", 19/32",9/16", 1/2" and 15/32"). Each drawer box thickness in these ranges require a different deduction dimension from the inside cabinet width.

[scott vroom]

Thanks for the reply Brett... So do you think the 12 15/16 drawer that I built is too wide?

Did you open and view pg 15 from the link Brett provided? For that hinge and a 1/2" drawer side thickness your drawer outside width must be 5/8" narrower than the FF opening. Simple really and not subject to interpretation. Your drawer box is too wide.

Did you not receive installation instructions with your slides?

For future reference: Blum tech support 1 800 438-6788. No reason you should have to guess or try to figure out how to install Blum products.

[charlie kapper]

I just glued up a new trail drawer and will test tomorrow. Thanks for all of the responses. charlie

[Leo Graywacz]

5/8" thick sides, subtract 3/8" from opening.

1/2" thick sides, subtract 5/8" from opening.

You need to realize the inside dimension of the drawer is what counts. The slides ride on the inside edge of the drawers. You can always double check this by installing the slides, pull the slides out, measure the outside dimensions between the two slides. This will be the inside dimension of the drawer box. Remember you need a bit of clearance so they aren't tight.

[Jerry Miner]

But wait!!! Don't throw that drawer box away! The Blum hardware mounts to the INSIDE of the drawer box, so you just need to add a spacer to the INSIDE edge --underneath (and maybe adjust the notch and hole in the back) to reduce the INSIDE dimension. You really don't even need a spacer---you just need to move the clip over that 1/16---to the INSIDE. Easy fix, really.

[charlie kapper]

This is an awesome site to get questions answered - issues resolved. I did make another test drawer. That 1/8" does make a difference. Another learning... I ordered 563H (full extension) slides and the design is inset drawers. After insetting the slides to allow for the false front, they are no longer full extension. No big deal but something I did not think about. I guess that is why it is always good to make a test run first. Thanks for all of the help and stay tuned as the kitchen project will begin soon and I feel confident I will be posting again.