Opposing Arch Table #6: Building the Arches... Design Challenges

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Blog entry by Blake posted 11-09-2008 10:32 AM 3859 reads 0 times favorited 10 comments Add to Favorites Watch
« Part 5: I Pulled an All-Nighter Part 6 of Opposing Arch Table series Part 7: Laminating the Arches »

Like I mentioned before, I am building a matching coffee table along with my “hall table.” I have been making an effort to document the time I spend on larger projects for my own reference. But since I am building two projects together the concept of time is getting a little blurry. I spent a few hours the other day just getting the coffee table caught up in the process. All the joinery is the same as before.

I decided to try taping my joints to make it easier to peel off the glue squeeze-out. It did help a lot.

Here it is with the glued-up top but I haven’t finished it yet. It still needs the beveled edges and a lot of sanding:

Lamination Forms

My Better Bond Ultra-Cat adhesive (as recommended by bfd) showed up in the mail today. But I’ve got quite a bit of work to do before I mix it up.

Here is the MDF I got for the bent-lamination forms:

I started by laying the table on the MFD and tracing the legs and apron:

Through trial and error I came up with a low-tech but effective method of precisely drawing the first arch on the MDF. I used a pen attached to a piece of string around four nails. Its not a simple radius but more of a “compound radius” since it is wider than it is tall.

Then I used a Kleenex box to mark a series of parallel lines that would serve as clamping areas around the curve after being cut:

I cut the straight clamping edges with a jigsaw and then cut the two inside curve lines on the bandsaw. Then I screwed one side of the form to another piece of MDF that will serve as a base to keep the lamination flat:

Mock-up of the arches

At this point, I am still doing a lot of designing “on the fly.” I was planning on making a prototype lamination to see how the shape looks. But then I realized that the arch that I cut out of the form was already the shape of the final lamination. So I grabbed it and attached it to the table to see how it looked.

Then I found some thin scraps that I bent into position for the smaller side arches as a mock-up:

Then I attached a few clamps to temporarily hold the lower shelf in position to get a sense of its location:

Design Challenges

My intention is to somehow attach the shelf to the arches rather than the legs so that it appears to “float.” I am having a hard time seeing how that is going to work now that I’ve got a tangible model to play with.

This is the reason I believe that Sketchup has its limits as a practical design tool. I personally need to literally put my hands on certain parts of a complex design problem to work out a solution.

I am also realizing, as I look over the original Sketchup drawings, that I had drawn the arches differently than I arranged in my mock-up (I didn’t have my computer in the shop with me). Notice how in the drawing the arches start at an angle from the legs as opposed to flush against the lower portion of the legs:

Another thing I am seeing at this point is how thin the “side” arches need to be in order to look proportionally correct, which doesn’t leave much room for a pin or dowel to attach the shelf on the sides. This is appearent in both the original Sketchup drawings as well as my model arches.

At this point I am unresolved in how to shape the arches and attach them to the legs as well as how to attach the shelf to the arches. I’ll have to sleep on it but would also love your input if you’ve got any.

I’ll apply today’s 4 hours of work to my timeline since I was actually working on the hall table… Total project time: 22 Hours

I couldn’t resist bringing the two unfinished pieces up from the shop and see how they look together in my living room. The coffee table will get arches as well (but no shelf)...

-- Happy woodworking!

10 comments so far

View Karson's profile


35111 posts in 4365 days

#1 posted 11-09-2008 03:24 PM

Great set of pictures Blake. Nice job on the design and on the implementation planning.

-- I've been blessed with a father who liked to tinker in wood, and a wife who lets me tinker in wood. Southern Delaware soon moving to Virginia †

View Thos. Angle's profile

Thos. Angle

4444 posts in 3927 days

#2 posted 11-09-2008 03:52 PM

Interesting problem, Blake. The dimensions have changed from the drawing to the actual table with the arches. Personally, I prefer the arches attached as you have them on the the actual table as opposed to the attachment in the drawing. The arch seems to flow out of the leg rather than being attached at an angle. You will think up a better way to attach the shelf than the pegs in the drawing. I’m not sure what that will be, but , knowing you it will be interesting to watch. Good luck.

-- Thos. Angle, Jordan Valley, Oregon

View Todd A. Clippinger's profile

Todd A. Clippinger

8901 posts in 4064 days

#3 posted 11-09-2008 06:41 PM


I agree completely with Thos. on the visual flow of the arch from the leg. The actual product is better than the Sketchup model.

I am fairly pragmatic about using available space in our tiny house. This side of me would lean towards adding the bottom shelf. But as I look at the photos, I think the table looks better without it. This is the purely artistic viewpoint.

I had Rita look at it too. We agreed on the bottom shelf. The table is light and airy with some great visual interest added by the graceful sweeping arches. The bottom shelf seems a bit heavy and out of place.

Leaving it out may be a consideration. Taking it in the house is perfect. Live with it in your space and see how it feels. Is it better with or without the shelf? How does it impact you when you first walk into the room? This is exactly what I am referring to when I talk about designing by “feel.” It is all about the initial impact when you see it. Does it feel like it is balanced, flows, or has a comfortable presence?

The actual table seems taller and not as long as the Sketchup model. The actual seems more delicate and is very pleasing.

This is a good experience to see how an actual project looks in comparison to it’s computer rendering.

-- Todd A. Clippinger, Montana,

View Blake's profile


3443 posts in 3839 days

#4 posted 11-09-2008 06:46 PM

My consultant (wife) is advising me to stick with the mock-up version as well. She also likes the way the arches flow into the legs. I think I like it better too and will probably stick with the new design.

-- Happy woodworking!

View GaryK's profile


10262 posts in 3953 days

#5 posted 11-09-2008 07:01 PM

Very interesting design, Blake.

If you don’t end up putting the bottom shelf in there, there is something you might want to do.

Connect the front and back arch with a round or twisting square rod. (Square twist to make each end mate flush with the arch.)

The connection point would be where they would intersect if they were both on the same side of the table.

As well as adding visual impact it would also serve to strengthen the thin arches.

-- Gary - Never pass up the opportunity to make a mistake look like you planned it that way - Tyler, TX

View FritzM's profile


106 posts in 3777 days

#6 posted 11-09-2008 09:09 PM

Well Blake, you’ve gotten to the heart of what it means to design on the fly. To me it appears the fundamental problem is that the table you designed in sketchup and the mockup have different aspect ratios. The model is much longer that it is tall while the real table is almost square in form (as Todd mentioned). This means the severity of the arches between the long legs is much less graceful and that is compounded by the addition of the intermediate shelf. Hence, I agree that the table without the shelf feels more well balanced. The truncated shape of the actual; table also makes the arch appear more of a single radius and less an elliptical form. This affects the look in a way that causes the curved form to make the piece unbalanced. I know it is quite a departure, but have you considered two opposing arches (curved as you have them mocked up) in the same plane? Meaning double arches between each leg? Or shortening the table to make it match the model more…..

It’s your vision and your design, I’m sure the right answer will come. What I do in this situation is exactly what you are doing. Keep mocking up (physically as well as in sketchup). I wonder how it would look if you moved the shelf up? Perhaps above the mid point of the legs and made it thinner and shorter (like the model). Keep playing with it, it’ll come to you. The beauty of this process is you will test options, evaluate their validity and relevance and test and cement your own design ideals.

Good luck man, keep us posted!


-- Fritz Oakland, Ca (dedicated to my other hobby)

View bfd's profile


502 posts in 3772 days

#7 posted 11-10-2008 04:04 AM

Hi Blake,

I was just wondering how you were coming on this the other day. Here are my thoughts. I think that once the opposing arches are in place they will help the piece looked more ballanced as it does in the rendering. I do like the way that the arch starts and terminates into the leg and apron in the mock up. I would keep the side arches the same thickness as the larger front arches. And I personally think the shelf helps in the composition of the piece. I think by keeping the shelf it helps reinforce the rectangular shape and lessens the look of a more square composition. If I remember correctly you were going to use brass rods (pins) to attach the bottom shelf. I think that you could get those small enough to work. The one recommendation I have is to put a bevel on the shelf (like you did on the top). This will help the shelf look more delicate and airy.

View BigBob's profile


64 posts in 3454 days

#8 posted 11-11-2008 11:28 PM

You really do exceptional work. This is real craftsmanship, when you build to your own design and try this and that until it looks right to you.
Awesome job.

View BigBob's profile


64 posts in 3454 days

#9 posted 11-11-2008 11:37 PM

If you want the shelf to “float” you might think about easing the edge of the shelf like you did on the top.
Champfering the edge gives it a lighter look , takes away the heavy feeling of it compared to the legs, top, and arches, and will help give an illusion of floating.
I think I would attach it with blind dowels.

View Blake's profile


3443 posts in 3839 days

#10 posted 11-12-2008 04:22 AM

I agree. I have been planning on chamfering the shelf (if I include it) all along.

-- Happy woodworking!

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