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 (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.

[Leo Graywacz]

I made an Excel spread sheet to calculate drawers for the Blum 563H slides.

I know it won't help your situation since it's long past, but maybe it'll help others. If you don't have MS_Office then you could download Open Office, it's a free download that will operate XLS files just as well.

Good luck.

[Max Neu]

I don't worry about the outside dimensions of the drawer box, the inside is what matters. I just subtract 1 5/8" from the opening, and that is what I cut my front and back pieces.My drawers are a but joint, so if you dovetail, you will have to use a different formula.You need to think bbackwards from the side mount slides, where the outside dimension was critical.By just focusing on the inside dimension, side thickness is irrelevant, as long as you are somewhere between 1/2 - 5/8" thick.

[Leo Graywacz]

True, this was for a 1/2" x 1/2" dovetail for the actual cutting list. But it does give the outside dimensions of the drawer with the correct inside dimensions calculated from the thickness of your stock. So anyone should be able to use it, just might have to do a bit more math to figure out your parts. Or just modify the formula for your situation.:D

[Max Neu]

I don't know why Blum uses those sizing charts,if they would just say something like this,
562H series (1/2-5/8" thicknes sides) -Make inside of drawer box 1 5/8" less than opening size.
562F series (3/4" max, thick sides)- Make inside of drawer box 1 15/16" less than opening size.
I think it would have saved alot of confusion.

[Mark W Pugh]

I don't know why Blum uses those sizing charts,if they would just say something like this,
562H series (1/2-5/8" thicknes sides) -Make inside of drawer box 1 5/8" less than opening size.
562F series (3/4" max, thick sides)- Make inside of drawer box 1 15/16" less than opening size.
I think it would have saved alot of confusion.

Actually the pix in the catalogue shows 21mm from side of cabinet opening to inside of drawer box. So, the inside drawer dimension is 42mm smaller than the drawer opening (i.e carcass opening or FF opening depending on style of cabinet). Clear as mud?

[Leo Graywacz]

That's the number I have in my calculations, 1.656" (42mm). Took me a bit to verify it because the middle ranges don't work out nicely. 16 and 15mm work nice as well as 12mm.

And clear as mud is why I wrote the Excel page, that way I don't have to think, just type in the numbers and it spits things out.

[Max Neu]

Actually the pix in the catalogue shows 21mm from side of cabinet opening to inside of drawer box. So, the inside drawer dimension is 42mm smaller than the drawer opening (i.e carcass opening or FF opening depending on style of cabinet). Clear as mud?
That's close enough for me, no need to split hair's on this type of slide. That's the formula my rep told me to use years ago, it has always worked flawlessly.

[Don Sundberg]

Blum has excel planning tools for a lot of its products.

http://www.blum.com/us/en/02/40/20/

This should link to the xls file I used when I did my undermount drawers. I messed mine up too but it was my fault not the programs.
http://d1.blum.com/BEC003/tandemplusbmn56x_pt_dok_bus_$sus_$aof_$v1.xls

Don

[Don Sundberg]

Using the Excel spreadsheet above I get for a 13 7/16 opening with 1/2" sides an ID of 11 25/32 or 12 25/32 for 1/2" sides.

Looks like you have a couple solutions for your first drawer. Good luck with the rest.

Don.

[Tim Bell]

I know this is an old thread but,

I just looked at some drawers I built about a year ago using the 563h slides. I used 1/2" ply for the sides and 3/4" ply for front and back. The plys I used are just a teeny tiny bit less than those measures.

I used the 5/8" blum rule to size my drawers. (so 17" opening = 16 3/8 box). Everything works OK but, it does appear to have about 1/8" gap between the slide and the inside edge of the side. Aren't the sides supposed to sort of hug the slides?

Reason I bring this up is I have to make a drawer and have a pair of the 563h. I saw an example on the web where a guy notched down some 3/4", making it 5/8" just where the side meets the slide. Was thinking maybe this would be a better strategy being that I only have access to 1/2 and 3/4". And, the 563h was made for 5/8"

As I said, it seems from what I've found that the Blum reduction of 5/8" from the outside width is a little light.

This is probably one of those 'don't sweat the small stuff' things but thought I'd put it out there for thoughts.

Thanks
Tim

[Leo Graywacz]

If you go to Blum's site and look up how to size drawers they'll give you the formula.

The outside dimension of the drawers isn't as important as the inside dimension of the drawer.

[Peter Quinn]

I know this is an old thread but,

I just looked at some drawers I built about a year ago using the 563h slides. I used 1/2" ply for the sides and 3/4" ply for front and back. The plys I used are just a teeny tiny bit less than those measures.

I used the 5/8" blum rule to size my drawers. (so 17" opening = 16 3/8 box). Everything works OK but, it does appear to have about 1/8" gap between the slide and the inside edge of the side. Aren't the sides supposed to sort of hug the slides?

Reason I bring this up is I have to make a drawer and have a pair of the 563h. I saw an example on the web where a guy notched down some 3/4", making it 5/8" just where the side meets the slide. Was thinking maybe this would be a better strategy being that I only have access to 1/2 and 3/4". And, the 563h was made for 5/8"

As I said, it seems from what I've found that the Blum reduction of 5/8" from the outside width is a little light.

This is probably one of those 'don't sweat the small stuff' things but thought I'd put it out there for thoughts.

Thanks
Tim

The blum formula boils down to subtract 5/8" from the opening for 1/2" drawer box material, to within a few thousands of an inch once you convert it to SAE. Frankly the difference in the plywood doesn't much matter on those slides but you could subtract 11/16" to make up for the 1/32" undersized plywood 2X if you really care to. My guess is if your sides are 1/8" off the slides either you miss measured the opening or the widths are not exactly right. But when you nail the numbers in both cases, use exactly 1/2" material, and use the 5/8" subtraction the drawers slip on like a glove...and not OJ simpsons gloves. If the drawer wont fit you must.....adjust it!

PS: I have run a very thin kerf up the bottom of the sides of a few drawer boxes in my past when the fit was just a bit too snug. You don't see this with drawer faces in place on applied fronts, drawers that are too narrow are a bigger problem on 563's than a bit too loose, so always err on the a little too big side if things are odd to measure, like 23 and "almost but not quite 3/8"....better to round up the width than down IME.

[Oscar Nunez]

Hi jeff if using 3/4" sides, how much do you subtract? Is it 1/4" (1/8 on each side)?

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

[Sean Tracey]

Drawer widths and slides are best done with millimeters. Much easier to measure and calculate.

[Leo Graywacz]

Hi jeff if using 3/4" sides, how much do you subtract? Is it 1/4" (1/8 on each side)?

I think it's 1/8". 5/8" sides you subtract 3/8". So you are adding a 1/4" when you are using 3/4" sides, so you need to subtract 1/4" from 3/8"

[Justin Ludwig]

The blum formula boils down to subtract 5/8" from the opening for 1/2" drawer box material, to within a few thousands of an inch once you convert it to SAE. Frankly the difference in the plywood doesn't much matter on those slides but you could subtract 11/16" to make up for the 1/32" undersized plywood 2X if you really care to. My guess is if your sides are 1/8" off the slides either you miss measured the opening or the widths are not exactly right. But when you nail the numbers in both cases, use exactly 1/2" material, and use the 5/8" subtraction the drawers slip on like a glove...and not OJ simpsons gloves. If the drawer wont fit you must.....adjust it!

PS: I have run a very thin kerf up the bottom of the sides of a few drawer boxes in my past when the fit was just a bit too snug. You don't see this with drawer faces in place on applied fronts, drawers that are too narrow are a bigger problem on 563's than a bit too loose, so always err on the a little too big side if things are odd to measure, like 23 and "almost but not quite 3/8"....better to round up the width than down IME.


Peter nailed it.

I subtract 11/16. I can use 1/2 or 5/8" material and it doesn't make a difference. When using 1/2" material, there is side to side play when the drawer sits on the slides NOT locked in place. Reference your back drilling jig to the outside of the box in either case. Create a spreadsheet with a formula to calculate your box pieces so all you have to do is enter your opening width and cabinet depth.

[Max Neu]

If you base you're formula on the inside box dimensions you won't get any side to side play,or snug fits,all the discrepancies get shoved to the outside,which doesn't affect the operation of the slides.

[Justin Ludwig]

If you base you're formula on the inside box dimensions you won't get any side to side play,or snug fits,all the discrepancies get shoved to the outside,which doesn't affect the operation of the slides.

That's true but you lose a little of the width of the drawer doing it that way; though, I doubt there's enough loss to constitute anything of worry for even the pickiest of clients (watch my next job be someone who walks around with a magnifying glass).

[Max Neu]

That's true but you lose a little of the width of the drawer doing it that way; though, I doubt there's enough loss to constitute anything of worry for even the pickiest of clients (watch my next job be someone who walks around with a magnifying glass).

I am more concerned about the drawers working properly than cheating someone out of a 1/16" of drawer space. :)

[Ellen Benkin]

Maybe I cheated but I sent the measurements for my drawer openings to a company that made all my drawer boxes. After reading all these responses I am glad I did!! The boxes also came with the notches and holes in the right places. Worth every penney!