confused on drawer dimensions for a Hettich Quadro slides

[Bob Cooper]

Long time user of Blum Tandems. i'm trying to make sure i can use the same dimensions for the drawer box. it's advertised in woodworker express as a 24" drawer slide but i cannot really find a clear spec in the docs for the outside drawer length. The one difference i notice is that blum calls for 21mm vs 20mm for the dimension impacting the drawer box width which makes me believe at least i need to make my boxes 2mm wider that normal.

Normally for Blum 21" slide using 5/8" material with attached faces my cliff notes are
- height = rough opening - 13/16 (21mm)
- width = RO - 13/32 (10mm) <-- this would be 8mm now based on the Hettich docs
- length = 21" normally but these are deeper thus 24" <-- this one i'm really not sure of for the Hettich

If you have experience w/these slides should i just make them 24" long?
Do you agree that these boxes should be 2mm wider?

Also this got me thinking about, even in the Blum case how can 21" box length (in the normal 24" cabinet) be stated w/o it being dependent on the front of the drawer box thickness. i know the hook goes on the back of the drawer but the orange clips butt up against the back side of the front...so it seems independent of how thick that front part of the box is. If the front of my drawer was 5" thick the slide would mount the same i'm thinking but the box would not match their dimensions. i'm sure i'm missing something as i've never had a fix problem before.

i may have to just mock up a simple drawer to make sure these work before investing in the final version.

here's a couple pictures showing what i ordered and specs

[Jeff Roltgen]

Bob,
As a long time Hettich Quadro V-6 and now 4-D user, for either one, it goes like this:

- Drawer length = slide length
- Drawer width, using 5/8" (16mm) stock thickness: opening - 3/8" = 3/16" side clearance (~5mm).
- When mounted on the slide, your drawer will have roughly 1/2" clearance from bottom of opening, and I personally like to match that at the top, so my formula is:
drawer opening height -1" = drawer box height.

Not clear if you are using V-6 or 4D. 4D is the newest version, and has lots more forgiveness on dimensions, as well as lots more adjustability. It is worth the extra cost in time savings.

Planning guide shown: Terribly confusing, as they are showing what appears to be 8mm side clearance on the right, though all I can assume is that would be with 1/2" (12mm) stock, so gap would decrease about 3-4mm from 5-8mm in that case. Also note, on that side of diagram, looks like drawer side is flush to bottom? No wonder you're concerned, as I am, after reading it!

Regarding the 20 vs 21mm question, looks like they are attempting to skip confusion of gap dimension, and telling you:
For 5/8" (16mm) box material thickness, subtract that dimension from 21mm, = 5mm gap, or roughly, 3/16" each side, so the formula stated above checks out.

Sorry, I just cannot switch my entire shop to metrics, but suffice to say, I have a general understanding as needed for euro systems such as this, and that the imperial (rough) equivalents work just fine with these slides. I really love them, especially since going to the 4D's. Since my local supplier only distributes this brand, I've used almost nothing but Hettich hardware for a decade and a half. Probably hundreds of drawers by now, using above formula that I burned into my brain long, long ago, and it works.

Jeff

[Jeff Roltgen]

Bob,
One more clarification on the slide length vs drawer length and the dynamics of variable drawer box material thickness:
Hettich's work perfectly with 5/8, they simply include 1/8" spacers for front mounting clips to make up difference if using thinner 1/2" material. They can simply be discarded when using 5/8 stock.

Also- the 4D's now have a spring-loaded sliding hook for drawer back catch. We accidentally made 24" sides 1/4" too short recently, yet this forgiving mechanism allowed us to proceed, as it has that much throw under length, and even more if you go over length.

[Bob Cooper]

Jeff:

thanks so much. So summarizing for 5/8" material

length = 24"
height = RO - 1"
width = RO - 3/8"
make sure the bottom of the drawer is 1/2" above the bottom of the side (poor choice of words but i'm sure you know what i'm saying).

i assume the hole in the back is the same location as the blum? <-- even this wasn't super clear from their diagrams

Here's a couple pictures - in case you can tell if this is a v6 vs. 4d. i'm assuming the older version even though i recently bought these.

BTW in the picture...do i need to use the small 1/8" offset? is that what you're saying i don't need if the drawer thickness is 5/8"?

2022-06-18 14.56.04.jpg2022-06-18 14.56.22.jpg

[Jeff Roltgen]

Bob,
Correct. As for back hole to drill: I've always used an Accuride drilling jig given to me by a rep years ago. They work fine for the Hettich, understood it's more or less universal, so thinking Blum is likely the same. Either way, looks like with 5/8 stock, the hole is located 7/8" in from outside of box, 7/16" above slide notch opening (base of drawer bottom).

Those are the V-6. 4-D's have gray clips and an additional plastic clip that you mount to back of drawer. Those clips self-align to the notch, and eliminate the need for drilling hook holes into rear of drawer box, and ultimately eliminate any adjusting of the rear hooks.
If your V-6's are a little fussy snapping in due to ply thickness variations etc., go ahead and bend/twist the hooks a bit for easier installation. No shame. Again, the 4-D's eliminate all that, but I just bought a set of 24" 4D's that hit me a little over $50 per drawer. Yikes!

Almost forgot - Yes, that spacer can be tossed since you're using 5/8" material.

I think you got this!

Jeff