Drawer + slider dimensioning tolerances?

[RC]

So I've finally begun building the drawers under our stairs and now that I'm finalizing the drawer sizes I bumped into and interesting question.

The slider dimensioning guide very nicely mentions that the slider requires 12.7mm of space and should be mounted near the centre line of the drawer side... but it doesn't give any indication on how much space/tolerance should there be to the runners.

What I mean is that since the staircase has a width of 848mm should I design the drawer to be exactly 848mm wide with slider hardware installed or should I leave some tolerance for the possibility of a non-ideal staircase?

Common sense would say to leave a mm or two on each side just in case, but then the engineer in me wants to do exact dimensions... (I'm using Accuride 3832 SC's as sliders)

 

[GarryMartin]

The Quick Reference for those slides has the following note;

For optimal performance, make drawer 1-1/16" [27.0mm] less than cabinet opening. Slides may not function properly if side space is less than .50" [12.7mm].

Reference
http://accuride.com/Resources/PDF/3832SC-R2-0611.pdf
http://accuride.com/Woodworking/Product/Details.asp?ProductID=46&CatID=2&ProductName=Woodworking-3832SC%20Self-Closing

 

[junk731]

For accuride slides the width of opening minus 25.5 to 26 mm for your drawer size. In your case 848 - 26 = 822 mm or you split hairs and make it 822.5 mm. You need the end of the slide to be almost fully exposed.

John

 

[tjbnwi]

Here's the 3832 spec. I make the box 1" smaller than the opening. They're the same slides I used on the vanity in Member Projects. Max width of the drawer with these slides is 16".

http://www.accuride.com/Woodworking/Product/Details.asp?ProductID=82&CatID=&ProductName=Woodworking-3832

Tom

 

[AlexR]

Here's one I did earlier.


You need to make sure carcase and drawer box's are very square. I add extra 5mm on these wide box's so leave 30mm. The runners have lugs which bend out with little help from pry bar to get box's shutting square. Just add packers behind once all works well. [wink]

 

[RC]

Really convenient that they don't put that sentence in the printed quick ref slip that comes with the sliders  [mad]

So basically I should not leave more than 0.5mm on each side according the the manual...

Hmm.. maybe I'll play it safe and leave 1mm on each side since as Alex mentioned there are those bendy attachment points to give way a bit.

Nice looking drawers Alex though I'm making mine to open forward between the steps (848mm x 350mm x 110mm (w x d x h) and I'll make sliders for my CMS-plates where you have drawers.

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Thanks fellows, So i guess the engineer wins this time  [wink]

 

[AlexR]

Oh I see, your drawers are only 300 odd deep so the out of square issues isn't such problem where the ones I do slide out 850mm.
I've seen a set stairs done with book case drawers like your planing.
Got say I wouldn't want to be standing on stairs pulling open drawer stepping back ..... [scared]

 

[Jonhilgen]

Just saw this on a website today...good timing.

 

[RC]

That's why I'm not planning on putting drawers all the way up. The three bottom-most steps are reachable while standing on the floor.

I'll be putting about three tool chests worth of random hand-tools into the drawers to have them in a more convenient place when needed (currently they are under the platform that is at the top end of those stairs and has a ceiling height of 1200mm and 3000mm of depth and is packed to the ceiling with *stuff*).
Anything beats trying to crawl under that platform to get a screwdriver or a wrench  [tongue]

Other stuff that needs to fit under those stairs are my Bosch mitre-saw, CMS-GE base, CMS-OF plate & accessories, CMS-TS55 plate & accessories, CMS-PS plate so I'll build some sort of slide/shelving structure at the back sort of like the Festool CMS-storage unit has. If I can squeeze somehow a systainer or two in there all the better, but I don't have high hopes on that one.

I'm still debating with myself would it be better to make the bottom most drawers deeper than the upper ones so that they would form a solid square block at the front of the space where it is too low to store anything underneath anyway or not. I'll do this to the bottom-most drawer (which is not seen in the picture) by putting there a 60cm slider instead of the 30cm ones I'll be using higher up. Another option would be to make the bottom-most one 900mm deep, second one 600mm deep and third one 300mm deep -> they would end at about the same distance at the back. Then I would need to build support beams for the sliders thou since only the first 300mm'ish is covered by the stairs side beams (whatever they are really called) and pose a problem in finding reasonable priced 900mm sliders.

 

[Sparktrician]

Despite the benefits of better space utilization, I question the wisdom of having drawers built to pull forward from under a staircase.  I can just imagine someone forgetting to close a drawer and someone else having a tragic accident.  When I clean the basement stairs here, I see the quantity of debris and dog hair that collects under and on the stairs, and can imagine all that winding up in drawers.  It makes far better sense to me to have the drawers and compartments open to the side as in the photos from AlexR. 

 

[RC]

Good point Sparktrician, I'll have to take that into consideration - maybe angle the sliders a bit to make them autoclose? The sliders are of the soft-close variety with a rather strong pull-in when closing so I guess they might work?

My original plan was to have a 900mm deep side-opening sysport under there that could hold two systainers per shelf sideways and have them open up forward. There is the second flight of stairs not visible in the picture above to the right to the second floor so there is just over 1000mm of space there to open into. 

The main reason why I scrapped my original plan of doing side opening drawers like Alex is that finding 900mm sliders at anything reasonable per pair was futile (most seem to range from £110-£150 per pair) and would have made the drawers cost prohibitive to build. These 300mm slides cost 15€/pair and the plywood + lumber something like 50€ on top of that.

If this doesn't work I can always build a similar dimensioned chest of drawers on the upstairs platform and use the drawers as is sliders and all. (Might actually make one anyway since the old 600mm wide one there is literally falling apart)

 

[Sparktrician]

Is it really necessary to have the drawers be full depth and need the 900mm glides?  If you have access to the back of the stairs, perhaps make the side-opening drawers less than full-depth and use the remaining area for one or two MFTs with legs folded and placed vertically on a wheeled cart behind a door? 

 

[RC]

I've now put the drawers together and installed them in place and I'm experiencing serious (I think its called) racking in two out three drawers. i.e. the drawer will slide reasonably nicely 2/3 of the way in and then get stiff at the end of the slide and start sticking on one side or the other.

The top drawer works perfectly and the two lower ones become heavy to close towards the end abt. 10cm / 4" from fully closed. I've tried to loosen the drawer slide rails to let any possible non-parallelism to go away, which didn't help, I've shimmed the middle drawers slides 6mm down from the step above to see if there is any kind of lifting happening towards the end that would cause resistance, didn't help.

The drawers are identical sized and they all get stuck in bottom two slots... I can't seem to find a difference in the openings sizes either thou its hard to measure exactly, but within a 1mm tolerance the stair rails seem to be a uniform width from each other.

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Any suggestions what might be causing this?

 

[farms100]

The stringers might have a twist  in them.

 

[galwaydude18@gmail.com]

Ya if there is a twist in the stringers one 1mm difference from the front to the back will make a huge difference with drawer runners. 1mm either too small and they won't slide well and eventually fail and 1mm too big and you will find it hard to either open or close the drawers. What I normally do is take 26mm off for the drawer runners and that is the size you make the the outside of the drawer box to.

 

[Jonhilgen]

Reiska,

When I run into this problem, I cut a board the exact width of the front of the opening, then "cram" it in the back to push the  back opening to the same width.  This is assuming there is enough space behind the drawers.

Jon

 

[semenza]

  In my experience it is most likely a small amount out of tolerance. It doesn't take much  for them to go from working very well to barely usable.  Even a small amount of wood movement can be enough.  If I am mounting the slides  directly to the carcass sides I will generally ere about 1-2mm on the side of making the boxes too small. In other words a tiny bit of extra space. Because if it needs correcting it is easier to add some thin shim material between the slide members and the  drawer box than it is to  remove material.

  In light of the tolerance problem I have started using Miller Fast blocks for the front and adjustable rear mount brackets. They sacrifice a little drawer space but the fit is easy to adjust and can always be  made to work well.  The front and rear point mounting also allows for a bit more flex in the slide so the slide is a little less dependent on an exact fit.

  You can play with the fit on yours by adding shims (flat washers  work well), or sanding the drawer box side thinner. Depending on which way you need to go. You can even do just the front or back  if need be. 

Seth

 

[RC]

Problem solved, thanks for your great suggestions.

A typical case of idiotitis combined with a 6-year-old distration generator when assembling the two last drawers...

So I had happily trimmed the back board to the right length to match the final front width after the dovetails of the first drawer (which worked off the bat) and when the next day I assembled the other two drawers with my son in tow while the wife was out in town I totally forgot about the trimming before assembly bit...
Both non-functioning 'identical' drawers were 2.5mm wider at the back than the front... DUH!  [embarassed]

Thank goodness I hadn't glued them up so it was just a case of a little banging with the mallet to get the dominoes out and trimming the back boards to the right length, punch the domino holes again at the cut end and bang them back in place. Works fine now.