Installing Soft-Close Undermount Drawer Slides

When I started building furniture and cabinetry- this was about 20 years ago- side-mounted ball-bearing slides were about the best thing you could get your hands on.  Things have really changed since then.  The big watershed moment occurred when I saw Blum's first soft-close undermounts: they seemed like magic, frankly.  The only trick was that they seemed, well, tricky. Installing them required a lot more planning and there were a lot more ways to screw things up.  So it was a bit of an uphill battle figuring them out, but the good news is, once you know what you're doing, they're actually not all that hard to use, and it is really satisfying when you get it right.  In this post I'll point out my method for installing soft-close undermounts; it is worth mentioning that the process applies to all of the many brands that I've tried.  By now, a ton of companies have introduced their own version of the original product, and they all seem to go in about the same.

In terms of price, I find that I can buy 21" undermount slides for anywhere from $15-$30 in my area (Northern Utah).  While I haven't found it necessary to go for an all-out splurge, a couple of features are nice to have and make it worth spending a couple of extra bucks.  I usually get slides that feature 4-way adjustment of the drawer fronts (this allows you to move them side-to-side a little bit) and an elongated hole at the back to accomodate wood movement when used with solid wood cabinetry.  I don't endorse any particular brand, so I suggest just looking around and seeing what looks good to you.

Build your drawers anyway you'd like- just make sure the bottom is set
into a groove that begins 1/2" from the bottom of the drawer stock.

This drawer was super simple- the parts were glued and pinned together
with brad nails.  Dovetails are nice but I didn't use 'em this time.

Make sure the drawer is square by measuring across the diagonals.
Don't use a square, it is not up for the job.  On a small assembly
of this size the diagonals have to match exactly- even a 1/16"
variation can cause misalignments later on.

To accommodate the drawer slides, the drawers need to be notched at the back.
I measure in 1 3/4".  A coping or jig saw works just fine.

The slides are a cinch to install.  They need to be inset from
the front edge (consult the manufacturer's instructions for the
exact dimension).  In this case, I added 3/4" because the drawer
fronts were inset from (i.e. flush with) the cabinet sides, top, and bottom.
The sides are secured with 3/4" screws.

At this point, I gently slide the drawer into
place.  This is because the slides have little
prongs on the back that will poke into the
back of the drawer back.

When you remove the drawer, you'll see a
pair of little dimples.  That's the spot to
drill 5/16" diameter holes to accommodate
the prongs.

Here's the drawer back with the holes drilled.

In addition to the metal slides, you'll also need to install a pair
of mounting clips (they're mirror-images of each other, so you'll
have a left side and a right side.  They go on the underside of
the drawer, are attached with a couple of screws.  You'll also see
 a couple of adjustments that might come in handy later and a set
of release levers that you can use to get the drawer out.

Now the drawer should function normally.  Just
push it gently back into place.  You should hear
a pair of clicks as the mounting clips engage
with the slides.

To install the first drawer front, I use a clamp and/or shims.
My other favorite trick of the trade is to use double-sided tape-
with the tape adhered to one surface, just line up the front
and push it into place.

With the drawer front temporarily aligned, I attach it with screws
through the backside.

The second set of slides is installed in the
same way.  In this case, I used a block of
wood that I ripped to the width that I
needed so that I could position the next
drawer at the right height.  Sometimes
there's some wiggle room in this part of the
 operation, and other times the tolerances are
quite precise.

Getting the edges inset drawer fronts properly aligned can
take a bit of work.  A belt sander and random orbit
usually work for me.

Once everything looked shipshape, I varnished
the drawer fronts.