Introduction

This series of blog posts outlines some of the construction details of my Hexagonal Cocktail Table project.

As I mentioned in the project description, this table is a reproduction of a commercially available table. The original has a metal frame and legs. My table is all wood and MDF, and attaching the slender legs to the relatively thin table top proved to be quite a challenge. I'll cover that more in a later post.

Earlier this year, I retired from my position as a software engineer at Bentley Systems, the company behind MicroStation, a very advanced CAD system. After using MicroStation for over 20 years, suddenly not having access to it left me feeling like a fish out of water. I chose SketchUp Make as a replacement and have been slowly learning it. This project gave me an opportunity to try it on a real project. Here are a few SketchUp renderings.

My next post will describe the most complex part of the project-the top assembly with all of the triangles.

Congratulations on taking a step away from the vile Microstation product line! (Just Kidding) I have not been able to take the plunge yet and try to learn Sketchup, but it looks like you have adapted very easily, your model looks fantastic! As a 30+ year user of your arch-rival (AutoCad) I have not been able to make the switch. Ahh for the simpler days of Digitizer pads and Pucks instead of a mouse and drop-down menus.

And an outstanding finished product with the table. I really appreciate the blog series on it.

 

Introduction

This series of blog posts outlines some of the construction details of my Hexagonal Cocktail Table project.

As I mentioned in the project description, this table is a reproduction of a commercially available table. The original has a metal frame and legs. My table is all wood and MDF, and attaching the slender legs to the relatively thin table top proved to be quite a challenge. I'll cover that more in a later post.

Earlier this year, I retired from my position as a software engineer at Bentley Systems, the company behind MicroStation, a very advanced CAD system. After using MicroStation for over 20 years, suddenly not having access to it left me feeling like a fish out of water. I chose SketchUp Make as a replacement and have been slowly learning it. This project gave me an opportunity to try it on a real project. Here are a few SketchUp renderings.

My next post will describe the most complex part of the project-the top assembly with all of the triangles.

Hi Jeff,

Hmm… an AutoCAD fan. I guess we can still be friends. Everybody makes mistakes…

Thanks for the comments on the table.

The SketchUp behavior that gave me the most trouble was the "stickiness". For example, drawing a line across a slab splits it into two facets. The trick I learned from a book was creating components from primitives as soon as possible. Then a line won't stick. I found the book SketchUp - A Design Guide for Woodworkers, by Joe Zeh very useful.

 

The Top Assembly

The top assembly is a three-layer sandwich approximately 1 1/8" thick.

The bottom layer is 1/2" thick MDF hexagon. I had never cut a hexagon before, so I searched the web and found the excellent article Cutting Hexagons on a Table Saw by Don Snyder (a fellow LumberJock who goes by StLouisWoodworker) to use as a starting point. The large size of my hexagon (23 3/4" across the flats) made it difficult to follow the article to the letter, but I did the best I could. The resulting hexagon wasn't perfect, but it was close enough.

At this point, I did not cut the triangular notches for the tenons. (That came later, after the legs were complete.)

The top layer is composed of 24 triangles. Twelve narrow isosceles triangles (with 120/30/30 degree angles) form the interior "pinwheel" or star, and twelve equilateral triangles form the perimeter. I again used 1/2" MDF for them (mainly because I started my test cuts using some 1/2" MDF scrap on hand). Cutting those triangles was not as difficult as I feared.

The middle layer is a 1/8" thick hardboard hexagon. Its purpose is combining the top triangles into a single unit that can be easily moved, sanded, and finished.

I started with the narrow interior triangles. Each is about 3 1/2" tall (as measured from the 120 degree angle to the opposite side), but that wasn't critical. I cut 4" wide strips of MDF, and I cut oversized triangles from them using my table saw and a miter gauge set to 60 degrees. The triangles' exact sizes did not matter, and their sizes didn't need to match. The important things were (1) that 120-degree angle and (2) that they were oversized. After I cut all twelve rough triangles, I trimmed them all to their final size (long side 11 7/8" long) using a simple jig and my crosscut sled.

I used a similar procedure to cut the twelve equilateral triangles. I cut oversized triangles using the miter gauge set to 30 degrees, then trimmed them to final size using another jig and the sled. The key thing here was sizing the triangles so the sides were the same length as the short sides of the interior triangles. (In the photo below, I used two cut offs to simulate one perimeter triangle, and I separated the work piece from the jig to make them easier to tell apart.)

After all of the triangles were cut, I dry fit them on the base plate. If I were Norm Abram, they would have fit together perfectly, with no gaps to be seen. Unfortunately, I'm not Norm, so there were some gaps. I played around with the positioning to minimize the gaps, and then I labeled each triangle. I mentally subdivided the base plate into wedges (so I had Wedge 1 through Wedge 6), and I assigned each triangle a specific on each wedge. That way, every time I test fit the parts (and when I did the final glue up), I put each piece in exactly the same position.

With that done, I veneered each triangle separately. I won't go into details about that. The only tricky part was making sure to rotate the veneer 30 degrees on each interior triangle, and making sure that the grain on the veneer on adjacent interior triangles formed a 'V'. I used the iron-on method with regular TiteBond and flush trimmed each triangle on my router table. Veneering was tedious, but simple.

Now I was ready to glue. To make that task easier, I first edge-glued the four triangles that formed each wedge together, using just my hands for clamping and alignment. Once those wedges dried, I glued all six to a hardboard backer board whose size exactly matched that of the base plate. (Flush trimming the backer using the base plate as a guide ensured that match.) It was much easier to keep the six wedges in place during gluing/clamping than it would have been to keep 24 triangles in place.

At this point, I had a single slab with all of the triangles. Because my backer board wasn't a perfect hexagon, I flush trimmed it to match the hexagon formed by the glued triangles. Then I flush trimmed the base plate to match. So, even through none of the three layers of the top assembly sandwich was a perfect hexagon, all size sides of the sandwich were flush.

Here's a photo of the top. (Ignore the legs for now.) If you look carefully, you can see slight gaps between some of the wedges. Before finishing, I filled those gaps with a mixture of white glue and sawdust. (Every time I sanded anything, I saved as much of the dust as I could.)

Note that I did not glue the backer board to the base plate at this time. That was the very last step of the project. With the triangles glued to the backer, I had a single sub-assembly I could sand and finish.

My next post will describe the table's legs and how I attached them to the top's base plate.

 

Legs

The table's legs are tall and thin, with a diamond shaped cross section. The outward-facing edges are beveled to 120 degrees to match the angles of the top hexagon's vertex angles.

After puzzling over how to cut those angles, I found a simple solution: make each leg from two triangular prisms, each with a right-triangular cross section. Then I could cut each leg half with a single 30 degree rip on the table saw. I was able to cut all of the leg parts from a 3.5" wide x 0.75" thick poplar board.

This photo of the bottom end of one leg shows the two halves. The cut faces are in the center. I used painter's tape and packing tape as clamps when gluing the two halves together. I cut each leg slightly long so I could trim the edges after gluing if they were slightly misaligned vertically.

The top 1/2" of each leg is cut into a tenon. The tenons were easy to cut using my crosscut sled. I set the blade height to 1/8" and adjusted the sled's stop so the blade cut the leg 1/2" from its end. Then I kept sliding the leg slightly to nibble away the wood to form the tenon.

The back edges of the tenons fit into triangular notches in the top's base plate. I also drilled a 1/4" through hole through each tenon to accommodate a dowel that I thought would strengthen the joint.

In addition to the tenon through hole, each leg also needed a stopped hole halfway up its back edge to hold a dowel that supports the table's shelf. I worried a lot about how to drill those holes accurately (particularly the shelf holes, which cut into a near knife edge). Much like the top triangles, it turned out to be easier than I expected. I cut two V-shaped grooves in a scrap 2×4 to act as cradles, and that worked really well.

Attaching the legs to the top

With the legs finished, I turned my attention to attaching them to the top's base plate. I thought this would be easy-just trace the leg tenons at the plate's points, cut the notches with my jigsaw, use the holes in the leg tenons as a guide to drilling holes into the notches, and glue/dowel the joints. Boy, was I ever wrong.

My first problem was that not all of my V-notches were accurate. Some were slightly skewed, and some were slightly too deep. I was able to address those problems with careful sanding and shimming, but that didn't end my problems.

The fundamental problem was that the joint was simply too weak. A 1/2" long tenon at the end of a 17" long leg glued to a 1/2" thick MDF plate just didn't work (even with a dowel supporting the joint). The table wasn't going to support its own weight, much less stand up to any sort of use.

So I devised a "solution": longer, thicker 3/8" dowels where the legs met the underside of the top plate, either glued in place or reinforced with a thin block. None of it would be clearly visible under the top of the low table. Drilling the holes was a snap, but a quick test fit showed that this solution accomplished nothing. Well, that's not true. The dowels acted like small angle indicators. Each should have pointed directly to the center of the top plate, but not all of them did. So they served to mock me.

I was close to despair. I had finished the hard parts, only to be defeated by these joints. I thought I might have to come up with an alternate leg design, with a thicker or deeper cross section, but I didn't want to ruin the table's looks. My wife had one last suggestion, one that I was trying to avoid. "Aren't there some kind of metal pieces that will support the legs?"

I hadn't wanted to resort to angle brackets, but I swallowed my pride and drove to Home Depot to take a look. Fortunately, I found some thin 1 1/2" black angle brackets with countersunk screw holes that I thought would work. I tried them on one leg, and they solved the problem nicely. But I had to accept one more insult for my lack of forethought. The brackets included 5/8" long screws that (1) poked out the other side of the top plate and (2) hit each other inside the leg. I was too stubborn to drive back to Home Depot to look for shorter screws, so I drilled every screw hole, drove a screw to tap every hole, and used the bolt cutter on my electrician's multi-purpose pliers to snip the end off each screw (48 screws in all). It took forever, but it worked. The table was stable, and the angle brackets wouldn't be very visible after I painted the table's frame.

I left the useless outer dowels in place. I figured I'd just mess something else up if I tried to remove them.

My next post will cover the rest of the project: trimming the edges of the top, adding the shelf, and applying the finish.

 

Final Steps: Top Trim, Shelf, and Finish

Top Trim

The top assembly "sandwich" is trimmed by 1/8" thick poplar slats that rest on the outer edges of the leg tenons. This trim and the legs form what is a metal frame on the original table.

I cut the trim from the same board I used for the legs. I attached it much like a trim carpenter installs base or crown moulding. I temporarily placed the top backer/triangles subassembly on the base, used a miter saw to cut the first piece (nibbling away until it was exactly the right length), then repeated the process for the remaining sides.

After I glued the trim pieces, the frame of the table was ready for paint. (Earlier on, before I attached the legs and trim, I had sprayed dewaxed shellac on all of the poplar pieces to act as a sealer.) For paint, I used Rust-Oleum metallic oiled bronze spray paint. It worked really well, and it does look like metal.

The Shelf

I'm describing the shelf out of sequence. Before I cut the notches in the top's base plate, I used it as a template for the shelf. First, I cut the shelf from a 1/2" sheet of MDF, and I flush trimmed it to match the top place. I then drew a line 1/2" from each edge, trimmed off the edges close to those lines with my table saw, and finished by clamping a board to each line and flush trimming to that. The result was a shelf inset 1/2" on each side when compared to the top's base plate. My rationale here was that, if the top place was not a perfect hexagon, I wanted the shelf to be similarly imperfect (same error at each angle).

After I cut the V-notches in the top plate, I used them to mark shallower notches in the shelf. Finally, I routed slots at each corner to fit around the support dowels in the legs. This shot from the finished table shows one of the slots. Note that I made them wider than the dowels to account for any slop in the leg's mounting angles.

At first, I veneered only the top and edges of the shelf. I know you're supposed to veneer both sides of panels, but I thought I could get away without it. However, a few days after I veneered the top side, I noticed that the shelf was ever so slightly dished. So I used most of my remaining zebrawood veneer on the bottom for peace of mind. I had to hand-trim the veneer around the dowel slots, but that wasn't too difficult.

Finishing the Shelf and Top

I decided on a simple oil finish for the top and shelf, and wiped on four or five coats of Watco (natural). That darkened the wood and gave it a very slight sheen, just like I wanted.

I've used Watco before, but the finish wasn't as smooth as I wanted. This time, I followed the procedure in the YouTube video How to Apply Danish Oil, by Fabian's Tiny Workshop. He demonstrates the process very clearly, and I'm very pleased with the results.

Attaching the Shelf and Top Triangle Subassembly

Prepainting the legs and top trim created one last problem: how to attach the shelf without marring the painted legs. This was a bit tricky. I placed the table upside-down on my bench, supported by bench cookies so I didn't put any pressure on the top trim. Then I wrapped each leg in paper and carefully slide the shelf (also upside-down) far enough to clear the dowel holes. Then I glued the dowels in place and slowly lifted the shelf to meet them. (I actually used my car's jack to do the lifting. It looked sort of weird, but it worked well.) With the dowels touching the bottom of the slots, I used a strap clamp to apply slight inward pressure on the legs, filled each slot cavity with white glue, then waited an eternity for it to dry.

With the shelf in place, all that remained was gluing the top subassembly. I did that upside-down too, but it was simple. I placed the inverted top subassembly on the bench, coated the backer board with glue, and gently place the assembled frame around it. (I did it this way because I didn't want to drop the top into the shallow cavity formed by the trim and have it fall in at an angle.) Then I turned the table right-side up and gently clamped it. Done at last!