Thursday, March 25, 2021

Demilune Table, Part 1: Design Considerations

We need a small table as a plant stand in front of the kitchen window.  The current table, borrowed from my sister, has two thick books on it to raise the plant to the height we wanted.

Not the ideal situation

I've wanted to make a Demilune table for many years.  So, not knowing any of the pitfalls of the design, I decided to jump in.  Soon, I started to realize all the complications.  There's the position of the front legs.  There's the rotational orientation of the legs.  There's the joining of the legs to a curved apron.  There's making the curved front apron without wood bending capability.

One of the questions fortunately had an easy answer, though there was some butt scratching about it.  Half-oval or half-round?  I love an oval shape, but we had decided the table needs to be about 24" wide and 12" deep.  That makes it a perfect half-round.

In this post, I'm going to walk through some of the design considerations.  This is as much to show readers my thinking as it is for me to work it out in my head.

I have a copy of Bill Hylton's excellent "Illustrated Cabinetmaking", and he's got a two-page section on demilune tables.  I could make this ultra-simple by going with a three-legged table having no curved apron, or I could challenge myself and try something tougher with curved front apron attached to legs.  My biggest challenge is how to make the curved apron, and I'll get into that more later.

Started with the plan view of the half round top

I thought it should have a 1" overhang of the top all around.  The legs will be a little proud of the aprons, so the 1" is from apron to edge of top.

Showing where the aprons will be

The position of the back legs is simple enough.  They'll be at the back corners, with the rear apron mortised into their inside faces and the curved apron mortised into their front faces.  But the front legs are another story.  I tried a couple different orientations.  This first one is with the legs at 45° angles relative to the rear edge of the top.

Front legs drawn, centered on lines 45° from back edge of top

A front view with the legs at that 45° position

It seemed to me that the front legs were not forward enough for front-back stability, so I tried legs at 60° from the top's back edge.

Front legs, centered on lines 60° from back edge of top

A front view with the legs at that 60° position

I liked this a lot better.  The picture in Hylton's book shows the legs closer to this position as well, though it doesn't give any details.

One might notice that the front surfaces of the front legs are parallel to the apron (or parallel to the tangent to the apron at that point), as opposed to being parallel to the back edge of the top.  This is a detail that I'd seen in Hylton's book as well as most online images.  This has advantages for joinery using a laminated apron, but might create issues for other methods.

Hylton shows different ways to work with the curved apron.  One could make a single-piece apron (OK, it's laminated, but one long laminated piece), mortised into the rear legs and joined to the two front legs using bridle joints.  The curved apron could be made via bent lamination, or by using the "bricklaying" technique, building the curve from vertically laminated and offset  pieces that are then cut on a bandsaw and finally veneered.  I don't have a bandsaw, and for various reasons I don't want to laminate the semi-circular full apron.  So I'm going to attempt to make this like I would any rectangular table: with the aprons having tenons that fit into mortises in the legs.

The legs shown above are 1.5" square, though I'll be tapering the legs down to 1" square at the bottom.  I had originally drawn them up at 2" square, but they just looked too big and chunky.  The choice of 3" wide for the apron was not totally random.  The legs will be 28 1/4" long and are only joined via the aprons, so the aprons needed to be reasonably wide.  The 3" aprons in the sketches above and below looked about right, and I think they'll give enough support, so that's what I'll go with.

3" aprons

4" aprons

Update: I've been experimenting with joinery and think I need to make the legs thicker at the top to accommodate longer tenons.  Here's a picture with 1 3/4" square legs that taper to 1" at the bottom.

The table with thicker legs

Unfortunately, it still looks a bit clunky to me.  But I need the mortises and tenons to be deep and long enough not to fail.  I'll get into that more next time.

Friday, March 19, 2021

Stack The Odds In Your Favor

On the desk-side table that I just built, I added a bead detail to the lower edges of the aprons and shelf rails.

Bead detail on a shelf rail

This one came out great, but it wasn't just dumb luck.  I hadn't put a bead on anything for a while, so I took the time to make sure it would come out right.

First, I touched up the plane iron with a strop.

The strop for a 5/16" beading iron is leather with compound on it, wrapped around a dowel

Then I practiced a few beads with some scrap.  This not only helped me get more comfortable with the plane, it also allowed me to dial in the iron's depth setting before using it on a project part.  Further, I got to see how it would perform with grain running in different directions.

In the pic below, you can see the wood grain runs away from the bead as the plane is pushed forward.  That's a sure-fire way to rag out the far rim of the quirk.

A practice bead on scrap

So I used the test bead to set a marking gauge to the extent of the quirk and ran a gauge line.

Running a gauge line

This really helped get a sharp edge at the extent of the quirk.  I started the bead cuts at the end of the board, moving back little by little before I took full length shavings.  This helps to minimize tear out in the event the wood grain is diving as you push the plane forward.

In the end, these few little things stacked the odds in my favor of getting a nicely defined bead.

The beads came out very nice with minimal sanding

If you haven't done a particular operation in a while, take the time to sharpen up, practice on scrap, and do whatever else is necessary to ensure a good result on the keeper wood.

Thursday, March 11, 2021

Desk-side Table, Part 4: Finishing Up

I was able to make the top from a single wide board.  The bottom had been flattened early on in the build and it sat for a while.  Thankfully, it moved out of flat very little, so planing it up went smoothly.  I wanted to shape the edges similar to what is on the desk it will reside next to.

The initial edge profile - the top of the top is at the bottom of the photo

I used a 1/2" radius on the top edges and about a 1/16" radius on the bottom edges.  These were done with jack plane followed by a smoother and a little scraping / sanding.  The corners were rounded with a 1" radius using a chisel, then a rasp and files.  I blended this curve with the existing profile curves.

Top with shaping done, ready for finish

The finishing started with a wipe with a damp rag to raise the grain and sanding after it was dry.  I would be staining the piece to look about the same color as the desk it will sit next to, so I filled the oak's open pores a bit with two coats of shellac.  The first coat is on in the picture above.  The stain was a single coat of Behlen American Walnut dye stain.  This product has acetone in it, but it also has some ethanol, and it seemed like it partially dissolved some of the shellac.  After that dried, I added two more coats of shellac to seal the stain.

Stain applied

I've had poor results when using fine steel wool on projects during the finishing stages.  I always get fine wool dust in the wood fibers that discolor it and end up wishing I hadn't done that.  But I felt that four coats of shellac might prevent these types of problems.  Before waxing, I rubbed down the whole thing with fine 0000 steel wool, which dulled the sheen.  Then I added a coat of paste wax using a cloth - not with steel wool as I've seen some people do it.

Waxing implements (the steel wool was used pre-wax)

I got an awesome finish!  The oak is smooth to the touch and reflects light nicely.

The last thing to do was to screw in the buttons that keep the top on.  I used brass screws, so I waxed them before driving them home.

Buttons installed

And here she is, ready for some thin cork foot pads and to be placed by the desk where it will live.

Side view

Front view

Installed in place

The color match with the desk is not quite right, but I'm happy enough with it.  The desk is a bit more on the orange side.

My wife likes it, but she would have been happy with something slapped together.  But really, where's the fun in that?  And I need the practice.  This was a nice project.  Having no drawer certainly simplified it, but she didn't want one.  Overall, very enjoyable.

Thursday, March 4, 2021

Desk-side Table, Part 3: More Joinery and Shaping

Continuing this week with joinery, the shelf support rails fit between legs in the short direction.  But the inside faces of the legs are tapered, so it's a little bit tricky to get the shoulder lines for the rails' tenons.

Getting the shoulder lines for the shelf rail

In the picture, I've dry-fitted the legs with a short apron and clamped it up.  I measured the outside-to-outside dimension of the leg assembly at the apron and used a little spacer to separate the legs just enough so that the outside-to-outside dimension at the bottom was the same as at the apron.  In the picture, the spacer is the stick just to the right of the tape measure.  With that distance right, I placed the shelf support rail in its proper orientation, but under the leg assembly, and knifed the shoulder lines off the legs.

I set a sliding bevel to that angle (which was the same for both shoulders on both rails) and deepened the shoulder lines, then carried the lines around the piece using a square and the sliding bevel.  The resulting shoulders fit perfectly.

Nice tight angled shoulder lines at the rail-to-leg joints

I used a similar method to get the shoulder lines for the three shelf boards, only these were not angled.  Then cut the mortises in the rails and went for an overall dry fit.

Mortises cut into the shelf rail, three shelf boards tenoned to fit

First dry fit - looking good

With all joinery complete, shaping was next.  I gave all aprons and shelf rails a bead detail at their bottom edges.

Using an old A.C. Bartlett's Ohio Planes 5/16" beading plane

Happy with the result on this shelf rail

Aprons and rails beaded - this looks so much better than the above similar pic pre-beading

I shaped the legs with a 1/2" radius on the outside edge and a much smaller radius (probably about 1/16") on the other edges.  That larger radius of the outside corners mimics the desk that this table will sit next to.

Top of leg showing the shaping.

I'll be attaching the top to the base with "buttons".  These used some off-cuts from the aprons.

Thicker part is 1 1/4" x 1 1/4".  The 3/8" thick tenons are 3/8" long.

After chopping the mortises in the aprons

Hide glue was used for final assembly.  First, the two short aprons and shelf rails were glued into their respective legs and set aside to dry for a few hours.  Then those short-direction leg assemblies were joined with the long aprons and the shelf boards.

Final glue-up

I'll wrap this project up next time with shaping the top and the finishing routine.