Hidden Pivot Bookcase Installation

Hidden Pivot Bookcase Installation

byGary Katz

Hinges and Wheels

I’ve seen and installed a lot of bookcase doors, many that swing on regular butt hinges. I’ve always used 4 1/2 or 5-in. heavy-duty ball bearing hinges, and they work alright, though the hinges tend to sag a little when the case is really loaded down with books. And they always need some adjustment down the road. Plus, they require a lot of jamb clearance, which has never seemed right to me. Besides, butt hinges only work on swing-in bookcases—there’s no way to hide them completely on a swing-out design.

I’ve also seen cabinet shops build these types of doors, using euro hinges. Trust me, those never work, no matter how many of those little hinges you use, they always sag. I’ve seen carpenters use piano hinges, too, but then it’s tough to take the case off or adjust the hinge. Besides, even a piano hinge is hard to hide in the trim on a swing-out case.

Swinging bookcases always sag a little, too. I’ve tried installing wheels and rollers on the bottoms of swinging bookcases, and they work okay, as long as the floor is a smooth, hard surface, and if there are no throw rugs, though sometimes the roller leaves a tell-tale track on the floor, especially over carpet.

When you use a roller, at the very least you have to leave a gap at the bottom of the case for floor clearance, and that’s a dead giveaway, too. Plus it’s almost impossible to really hide the joints in the baseboard, no matter how cleverly you disguise them. From what I’ve learned, the best way to design and build a durable swing-out bookcase door, one that can be adjusted easily, and one that’s truly invisible, is to design the door to swing above the baseboard, and hang it on a center-hung pivot hinge.

Start With a Drawing

There are few projects I work on today without doing a scale drawing first. When in comes to bookcases, especially swinging ones, SketchUp has saved my life. I started this project with a two-dimensional drawing, one that allowed me to pivot the door in the drawing. That’s how I found the correct location for the pivot point, which took some experimenting.The two most important issues are: 1: The case has to swing clear of the hinge jamb; 2: The case has to open 90 degrees. If you don’t know how to animate Sketchup drawings, watch this tutorial that Todd Murdock has put together:

I wanted the case to have a minimal amount of clearance between the jambs, so it would just clear the trim on the hinge side, and wouldn’t require wide trim on the strike side. That clearance is determined by the setback of the pivot perpendicular to the face of the wall.

(Note: Click any image to enlarge)

When wide open, the door butts against the trim on the hinge side. That clearance is determined by the depth of the bookcase and the location of the pivot, measured from the hinge jamb toward the strike jamb–parallel with the wall.

Bottom Clearance

The real improvement in this design is swinging the bookcase above the baseboard, so it won’t drag on a throw rug and can be trimmed out without any visible gaps. I wanted to end up with the case about 2 3/4 in. above the floor, to clear 2 1/2-in. baseboard. For a taller base, the bottom of the case would be even farther from the floor. If you’re not familiar with Rixson pivot hinges, scroll down to that section below right now.

Another drawing, this one three-dimensional and detailing the hinge parts and clearance requirements, confirmed that mounting the pivot base on two layers of 3/4 plywood would get me close to 2 1/2 in. above the floor. Because I could install the toe kick after swinging the case, the exact dimension didn’t matter, which made execution a lot easier.

Bookcase Construction

(Note: Click any image to enlarge.)

To prevent the case from sagging, I dadoed the sides to accept the shelves (see photo, right), something I don’t always do for built in cases. For cutting dados, I normally use a templates guide on my router, which makes it easier to build a compact template, and provides a cleaner tighter dado, but I was lazy. I didn’t have a Porter-Cable-style 3/4-in. template guide for this new router, and rather than running to the tool store, I made the router template exactly the width of the router base. I installed the cross pieces allowing enough space for both bookshelf sides plus an extra 3/16 in.—so I could slide the template up and down without hanging up—and used a long shim and spring clamps to lock the template in place.

An even easier tool for cutting dados is a Festool MFT table and router guide rail. This system is designed perfectly for the task and requires no template and no special clamping setup. Simply layout the book shelf sides with clear pencil lines for each dado (I used a Sharpie so the lines would be more visible in the photographs). Rather than running my router bit dangerously close to the guide rail, I adjust the router so that it cuts almost 1/4 in. away from the rubber edge.

To make it easier to align the boards for each cut, I attached a sacrificial fence to the table. The first pass cut a neat dado in the fence, and I aligned all the cuts with that dado. To make sure the boards didn’t slip as I moved them through the cutting station, I screwed a 3/4 in. cleat on top of the layout marks for one of the shelves. Once that cleat came up near the guide rail, I removed it and pressed it into the dado, where it locked the two boards together.

Here’s a trick I learned at Festool School: the dust collection system will collect almost all the saw dust if you don’t dado right through the first piece. Instead, plunge the router into the workpiece about 1/2 in. from the edge, cut the dado, then clean up the front when you’re finished. That little dam is all that’s needed to stop the dust from shooting out the dado, leaving it at the mercy of the dust collector.

Edgebanding Plywood Shelving

I’ve done a lot of edgebanding and always hated the hair-line crack that develops between the plywood and the solid stock. That gap is caused by the inner plywood endgrain swelling from the glue, which puts a little belly in the edge and forces the banding away from top and bottom of the plywood. To prevent edge swelling problems, I used a Collins Ply-Prep bit ($20.00) and ‘routed’ a slightly concave nose on each shelf. /
/ In order to work properly, the Ply-Prep bit requires a router fence with infeed and outfeed surfaces slightly offset to accommodate the very slight amount of material removed from each shelf. I made a shallow pass, less than 1/16 in. deep, half-way across a temporary fence. A line etched into the bit helps center the bit vertically on the stock, which is vital—otherwise the edge won’t be cut square.
After fastening the solid mahogany banding on with glue and 23ga pins… /
…I ran a laminate trimmer on each side to cut the surfaces flush. /
/ The last piece I milled was the strike side of the case, which required a bevel. I made the first cut on my table saw, but the blade height wouldn’t cut to daylight, so I cleaned up the bevel with a power plane.

Assembly

Before assembling the pieces, I pre-finished everything, a lesson learned the hard way after making dozens of bookcases—it’s just too hard to finish all those inside corners and edges without getting runs, drips, and finish all over my wrists. I used a water-based polyurethane and a roller, brushing out each piece to remove air bubbles. If I were smarter, I’d own an HVLP (high-volume, low-pressure) system, and spray the three coats on, but I’m not, and so I don’t.

/ To ensure a tight box that wouldn’t sag, I glued and fastened the shelves with screws, too, brushing the glue into each dado.

Finished sides, added after the case is swinging, cover the screws. I also cut the finished sides 1/2 in. wider, so that they cover the 1/2-in. plywood back.That way, the sides don’t require rabbets.

I glued and screwed the back flush with the sides, so that the case would never rack.

Hardware Preparation

Pivot hinges are the only way to fly when it comes to supporting a heavy bookcase and achieving an invisible door. I used a Rixson Model 370 bottom pivot, which can accommodate up to 500 lbs. and doors up to 3-ft. 8-in. x 8-ft. 6-in. The bottom pivot includes two pieces: the bottom pivot spindle which mounts directly to the floor (upper right, in photo to the right), and the bottom bearing (lower right), which must be mortised into the bottom of the door. The top pivot is a standard model 340, consisting of a retractable jamb-mounted pivot spindle and finished cover plate (middle and upper left), which are mortised into the jamb head, and a top guide (lower left), which is mortised into the top of the door.

I learned a long time ago to always make templates for door hardware, especially hinges—first, because it’s easier to position and cut the mortises perfectly, which means mortise depth, too; and second, because once you’ve used any special type of hardware, you’re bound to use it again and soon—it’s just a law of the jungle, like thermodynamics. In this case, the bearing guides and the top jamb pivot are the same width and thickness, but because their centers vary, along with their lengths, each piece of hardware requires a custom template.

I started by ripping stock for the center spreaders. A standard door-hanging template guide and router bit (1/2-in. bit and 9/16-in. template guide) will cut 1/16 in. short of the template bushing, so I made the template openings 1/8 in. wider and longer than the hardware. I ripped the spreader stock to 1 3/8 in. for the 1 1/4-in. plates. I centered the spreaders between two outer rails, spacing the spreaders apart the length of each plate plus 1/8 in., then fastened the templates together with pocket screws.

/ The centers vary on each piece of hardware, so make individual templates, one for the top guide and one for the bottom bearing (on left).

Laying out the template stops was critical because that’s what positions the pivots perfectly. For each template, I marked a center line on both axes (parallel to the wall, and perpendicular to the wall), then measured from those center lines to locate the stops. For the bookcase templates, I measured 2 1/4 in. from the pivot center to the back of the first side, knowing the second finished side would add an additional 3/4 in., resulting in a 3 in. backset. For the front backset, I measured 1 3/4 in. from the pivot to the front of the template, and I attached stops on that line.

/ Setting the router depth was simply a matter of adjusting the depth stop above the turret to exactly the thickness of the hardware.

I clamped both templates to the case and mortised the brackets without a second thought.

I fastened the bottom bearing immediately (below, left), pre-drilling the double-thick bottom shelf for the #10 screws. The top guide (below, right) mounts flush with the top of the case-the bushing must be mortised into the case. I traced the location of the center of the bushing…

…drilled out the hole with a paddle bit, then mounted the bracket. The top shelf is only 3/4 in. thick, but a false shelf, installed after the case is swinging, hides the bushing.

I designed the case 3/4 in. short to allow for this second jamb head, which I mortised in my shop, before installing the case. /
/ The top jamb bracket includes a linkage arm that draws the pivot spindle out of the top bushing in the case, so it’s easy to install and remove the case or a door. I drilled a 1 in. hole at each end of the mortise for the linage arm…
…then I connected the holes with a jig saw. /
/ At the closet door jamb, I traced the mortise for the linkage arm onto the existing head jamb.

Then I drilled out and cleaned up the mortise, and installed the top jamb pivot. I can’t stress how important it is to check the laser plumb dots by also measuring to the jamb—regardless of what type of door you’re hanging, whether it’s new construction or a remodel. Remember, the jamb might not be plumb and you have to hang the case to ‘fit’ the jamb! It’s vital to have a complete understanding of the whole picture, otherwise you have to move hardwareafter everything is installed (one guess how I know this).

Sometimes, dead plumb and perfectly square aren’t the only concerns when hanging a door, bookshelf or otherwise. I wanted the ‘door’ to fit the jamb, with even gaps. The opening was a little cross-legged, too, and I wanted the casing to fit flat against the case—the case had to be almost perfectly flush with the jamb. The measurement mark was off by only 1/8 in., so I followed that rather than the laser plumb marks.

A laser works great for transferring the plumb line. Just place the red dot on the center of the top pivot and mark the location of the bottom pivot.

Rixson also offers an accessory plumb bob that mounts directly to the top pivot—a slick way of finding the bottom pivot location. /
/ Notice that the bottom support base is 1/2 in. back from the face of the jamb. That 1/2 in. allowed me to recess the bottom toekick so the case would project over the kick, thereby hiding the 1/8 in. gap between the top of the kick and the bottom of the case.

Hanging the case isn’t difficult. Like with most doors, I retracted the top pivot spindle by backing out the set screw. When I’m hanging a door, I usually set the door perpendicular to the jamb, place it on the bottom pivot, then lean it back against the top pivot.

That way, I have comfortable control over the door while backing out the set screw and retracting the top spindle. It’s easy to position the door directly under the spindle, then run the set screw back in, pinning the door into place. But with a bookcase it’s not so simple.

Fortunately this was one problem I anticipated, which made me feel pretty good. I made the case 1/4 in. short of the opening, providing just the right gap between the top of the case and the head jamb. I backed out the set screw half way, then placed the case on the bottom pivot and straightened it up in the opening. The top of the case barely scraped across the bottom of the set screw, while the top jamb pivot spindle dragged over the top of the case and then dropped like magic right into the pivot guide. Amazing!

I installed the false sides on both sides of the case, driving fasteners from inside the case, so they wouldn’t be visible as the ‘door’ opened. Of course, no one would ever see the finished side near the hinge, unless they stood inside the closet.

Before starting the trim, I installed a shim made from UHMW (ultra-high molecular weight) plastic, which is pretty slippery stuff ($18.00 from I ripped a 1 1/4-in. length of the material from a 3/4 in. x 12 x 12 blank ($17.00), then I cut a long shim using a Festool guide and saw. I sized the shim to just touch the bottom of the case when the door is closed, which prevents any minor settling. That way, moving joints in the trim at the top of the case stay tight.

Trimming the top of the case is tricky. The joint between the architrave molding (parting bead) and the top of the case must be invisibly tight, yet still provide 1/16 in. clearance for the case to swing. And that’s where I made another mistake. I should have ripped the new top jamb down—to make it at least 1/2 in. back from the face of the jamb—so that the architrave molding would run back inside the jamb, past the bookcase, which would help to hide the joint.