ARTICLES & REVIEWS

Making a Variable Height,
Swinging Flip-Top Table

### by Garrett Lambert

Our boat needed a small-ish coffee table that could be raised for dinner for two, or for dinner and bridge for four. We looked hard but found nothing available commercially. The solution was to make one, and this one does it all:

Coffee Table mode, 20" high, 30" by 15" top

Pivoting to full-top position

Flipped open for dinner and bridge for four, 31" high, 30" x 30" top

The top consists of two identical pieces, in this case ¾" ply laminated on both sides with Formica and edge trimmed with mahogany to match the rest of the boat. The aprons are an open box, 2" solid mahogany—narrow because seat heights on the boat are 20"—with a ¾" plywood bottom assembled with pocket screws.

The only difficult part to the top and aprons is determining the pivot point, as considerable precision is required to have the top overhangs line up perfectly on all four sides in both open and closed modes. Basically, you…

1. lay the apron assembly on the top as it would be seen from underneath in the open position, and draw diagonals from the corners of the top across the base—it helps to have a solid base for this step…

2. lay the apron assembly on the top in the closed position, and…

3. picking one of the diagonals, find the center-point of the distance from the cross-over point of the diagonals to the overhanging edge of the top—not the edge of the apron—and that, theoretically, is the magical pivot point.

Unfortunately even a small error produces a top that is visibly mis-aligned. You will thank me if you take my advice and make a full-size blank out of ¼" material, because after several tries it was clear that the theory delivers a pivot point that in practice is close, but not dead-on (I have to make another half top as a consequence of assuming the geometry and I would be perfect…we weren't, and I ended up with a pock marked under-side). By drilling a 18" hole through the mock up and the bottom of the apron assembly for the pivot point and using the drill bit as the pivot, I finally found the right spot, and carefully circled it.

I made the full-size pivot as follows. I bought 2 38" tee nuts, one that hammers in and one that has three small holes in a smooth flange. I drilled the threads out of the first one and used it as a bearing, counter sinking it into the bottom of the apron assembly with a 1" Forstner bit.

Overkill, perhaps, but I also took a scrap of aluminum, drilled a 38" hole, and screwed it to the other side of plywood. There will be no slop in this assembly! I countersunk the other T nut into a piece of 1" maple and screwed that into the underside of the pivoting half top.

Assembly is just a matter of inserting a 38" hex bolt through the apron assembly into the second T nut. Note: This is the only fixed connection between aprons and top, so the table cannot be lifted by top. I installed a 1½" brass barrel bolt to one of the long aprons and drilled two matching holes in the underside of the fixed half-top so that it cannot move in either the open or closed position (visible in the next photo).

These tables are usually made with four legs if single height, but because we required variable height, I purchased and modified a heavy restaurant pedestal from a used furniture store. Normally, a long bolt runs through the tube to the top spider to tie the three pieces together. I cut the tube down, and welded a nut inside it at the bottom so I could attach the tube to the base. I glued up a wooden blank and turned a 2 ¾" dowel to an easy fit inside the tube. I then made three shallow grooves along the length, and glued in rub strips that I hand-planed to make a smooth-sliding “piston" fit (don't want any wobble). That done, I drilled a 1" hole most of the way through the length of the dowel— I needed to keep the lower 23 clear for the next step—and then drilled the remainder all the way through at 38" so I could bolt the dowel to the spider.

 Underneath With all the pieces assembled, I drilled a single through hole at the top of the tube and a series of matching holes through the lower part of the dowel. Inserting a brass pin—an old piece of a drain stopper—provides the desired height.

. . . Cheers, Garrett Lambert