Designing a dining carver chair

[Derek Cohen]

Shaping the legs have been set aside until the seats are carved. Shaping the seats is a challenge I have been looking forward to, but I must admit that two days have passed, and there is not much to show for a lot of effort. Let's have a look at the design of the seats.


The notable feature of these chairs is that they do not have a single straight line. Anywhere. There are three design aspects ...


Firstly, the plan for the seats will be curved like these ...





However, they are to be 35mm high at the sides, and recessed like these ...








The underside must curve sympathetically with the seat ...





The third factor is that the seats will be attached to the legs with mortice-and-tenons, and will not rest on stretchers, as most chairs appear to do (and seen in an example, above). The reason for this is to increase the appearance of lightness. Shaping of the seat has to make provision for the integral tenons.


The seats are to be shaped with a combination of power- and hand tools. Power is needed .... this is Rock Maple!


I spent time building a router sled to curve the tops and bottoms of the seats. The tops are documented here.











Today was 37 degrees Celsius (99 degrees Fahrenheit), and it was HOT in the unconditioned workshop, all windows and doors closed to be kind to neighbours. And it was slow going pushing the router back-and-forth. Plus it was messy ..





This was the result of my labours: two boards with the initial curves on their tops. These boards started out at 50mm thick.





There is a template for the basic shape. This is simply to position the tenons. The outline will be modified later ..





The section for deeper hollowing is marked out, and a grid created to position 10mm holes through the centre and 5mm holes at the sides to guide waste removal ...





A scorp was used to remove the bulk of the waste ...





This was hard work - the Maple is hard stuff - and the next seat will use a different method. That will be revealed in the next post.


Shaping is done with travishers. I have two I built with different radius soles. This is one ..





The result of my labours .... across the width ...





And through the centre ...





Lots of shaping still to be done at the front and underside.


In addition to the hollowing of the seat for comfort, the extra depth at the rear creates an effect tilt towards the rear legs. The amount of seat tilt can also be adjusted via shortening legs, if needed.


More soon.


Regards from Perth


Derek

[Tony Shea]

That's amazing Derek. I really look forward to this build thread, this has to be one of my favorite chair designs.

I feel your pain with shaping a seat in rock maple! I made a Perch Stool a couple year back all in rock maple. I carved the seat completely with hand tools which I will most certainly never do again. I also don't own a lathe and made the legs/rails completely by hand as well.

Stool.jpg

[Derek Cohen]

That's a nice stool, Tony. Beautifully shaped.

I built these three stools in Hard Maple for the kitchen a few years ago ...



Beautiful wood, but a buggah to work.

Regards from Perth

Derek

[Jim Koepke]

Thanks Dean and Jim. Dean, it sounds as though you prefer the look of squared ends, but Jim you do not say which you prefer. Will you say? And any other views, with explanations hopefully ...

Regards from Perth

Derek

My choice for something like this would be rounded through tenons. The would be made proud and rounded over the proudness. To me that feels more voluptuous.

jtk

[Jim Ritter]

Another thought in the rounded tenons, with the somewhat delicate dimensions of the legs a square corner could encourage a split.
Thanks for posting Derek, all good information.
Jim

[Derek Cohen]

My choice for something like this would be rounded through tenons. The would be made proud and rounded over the proudness. To me that feels more voluptuous.

jtk

Jim, raised tenons look good on tables and a good idea for another time. bThe aim for these chairs is minimalism and sleekness, and I think that the "bumps" will detract.

Regards from Perth

Derek

[Derek Cohen]

Another thought in the rounded tenons, with the somewhat delicate dimensions of the legs a square corner could encourage a split.
Thanks for posting Derek, all good information.
Jim

Thanks Jim - another good reason to use round tenons

Have you retired now?

Regards from Perth

Derek

[Derek Cohen]

The initial carving of the second seat ... time to learn something from the initial carving of the first seat! Rock Maple is bloody hard stuff. I have used a scorp to quickly carve Pine and Tasmanian Oak. I used a scorp to scoop out the first seat, and it was not fun in 37 degrees Celsius (98 Fahrenheit). Well today it is 39 degrees Celsius (102 Fahrenheit). Time to try something new.


Here is the second seat, which has been curved on the router sled ...





My 74th birthday present (3 days ago) was an Arbortech Turbo Plane kit ..





This can be set up in three ways: it can plane/joint rough boards, it can sand boards, and it can carve ...





It has variable speed, but I found carving is best at the fastest rate. Most importantly, it has some of the best dust control one can imagine. There is barely any chips to be found.





The Turboplane was impressively fast in taking the surface down to the drilled depths ..





It is an angle grinder, and noisy, but less so than a router.


I mentioned that is is a sander as well. I took the opportunity to try this out. 60-grit was rapid, and left a surface as smooth as a baby's bum.





The second new tool used was one I made ... literally in about 10 minutes at this point in time. I had a small coffin smoother, about 4" long, with an open mouth and a single iron. It had been purchased in an "antique" shop for a few Dollars several years ago for the express purpose of turning it into a chairmaker's plane. I admit - I procrastinated ... until today. These are curved front-to-back and side-to-side. It was not much work, and this is what materialised ...





The iron was rusty, and simply flattened on the side of a 180 grit CBN wheel, and then shaped to match the curve of the plane. You can see that the camber is more like a jack plane than a scrub.





How did it work? Brilliantly! Really, after using the travishers, this plane left them in the dust ...





There are a couple of red arrows in this photo. The upper one points to the added curved side lines. The seats were temporarily made with straight sides, but they will have a slight curve (no straight lines on the chairs). The second red line points to where the front of the seat ends. It will be cut off at this line.


The photo below shows the outline of the seat prior to the underside being curved in the router sled. Note the sections left for the tenons, and the red lines here represent the angle these will be (20 degrees at the front and 10 degrees at the rear) ...





Finally, the router sled was converted from convex to concave ...





That is for tomorrow.


Regards from Perth


Derek

[Jim Ritter]

Yes I retired in the sense that I rarely work on anything that has a deadline, lol. I’m helping on rebuilding a 62’ schooner when I can and when I want, and I do a lot less for money and more for friends and neighbors. Currently working on storm cleanup and rebuilding. The Maine coast was ravaged by these last two storms. Sorry for the thread drift.
Jim

[Tony Shea]

That Arbortech Turbo Plane is amazing! The fact that there is little to no chips is hard to believe with that tool. The mess a tool like that leaves behind is the primary reason I wouldn't use it, but if the dust collection is that good I really need to look at getting one.

[Derek Cohen]

Tony, it really is that good and dust free. The dust chute can either be used with just a hose (which is supplied), as internally there is a little fan to push the dust down the hose, where it can be expelled into a box. Or use a vacuum cleaner, as I did, attached to the inlet. Google YouTube for a video.

Best of all, these are designed and manufactured here in Western Australia!

Regards from Perth

Derek

[Derek Cohen]

Andy, on the WoodHaven forum, left a message which was remarkably predictive of what I had planned to write.

For me, the interest is in the problem solving. To make a single chair, with all parts curved, would be a challenge. But to make a matching set, you are going to need a tight system of reference edges and surfaces, to be removed only when all shaping is complete. Your methods so far make sense - of course they do! - I just mean that it sometimes takes me a minute to catch up and see why you are making a part the way you are. I'll be happily admiring the rest of the build.

Andy, spot on! In fact, you preempted the very topic I planned to write.

Everything in furniture building requires forward planning. This is even more the case where, as here, these chairs have not been built before, do not come with plans, and are based on sketches I have made. One sees chair builds on YouTube where the Maker lays out a template, cuts it out, finishes it with a template router, and then starts glueing parts together. If only ...

When one looks at the chair design, attention is taken by the arms and back. Yet these are aspects which will be approached last. Far more important is the seat, since this creates the plan for the arms. But, building a seat like the one envisioned is complex as it has two shaped sides, a top side and a bottom. Most seats are carved only on the top, with the underside being left flat.

In addition, I have seen very few seats which are attached directly to the legs. Almost all rest on stretchers, with the stretchers morticed to the legs (e.g. The Chair). The latter is easier to construct as you build two sides, and then link them. With integrated tenons in the seat, one has to make allowance for the tenons, and these need to be cut at the correct angle before the underside of the seat can be shaped. The reason for this is that we need a flat reference edge to mark the tenon angles (which come from the drawing).

Here is the seat at the end of the last post ...



The underside is flat at this stage (being the reference sides), as are the sections where the tenons will project. But ...

While I am confident about the angle of the tenons, I want to be sure of this, and this requires that the legs be clamped to the ends of the seat at the angle predicted. The legs have been left flat - not yet rounded - as it is easier to add a mortice at this time.

So the next stage is to do just this, but I only have legs for one chair. As a result, work stopped to complete the other four legs. First, a section was cut off one of the 3m long (x 250mm wide x 50mm thick) Rock Maple boards (my wife helped me load this!).

Easier to crosscut on a MFT with a tracksaw than a tablesaw. Mine is a 20 year old Festool I purchased about a year ago in as-new condition.



The section was re-sawn to 32mm and then planed to 30mm. Great tracking by the combination of a Hammer N4400 (which I have had for about 15 years) and a 1" Lenox Woodmaster CT blade ...





As I mentioned in an earlier post, it is less stressful to mark the legs with a template, bandsaw to the lines, and then use spokeshaves to clean up. Here are some of the spokeshaves I use ...

A Stanley #84 boxwood spokeshave excels in taking thick shavings. This is where I begin ...



Veritas make a copy of this in the form of their LA Spokeshave, and it is very good (I use one or the other, not both) ...



Many years ago I was gifted a flat and round spokeshave by Terry Gordon (HNT Gordon tools). It is a Malaysian/Asian design with a high cutting angle. This is my go-to if there is any reversing grain ...



Lastly, the LN Boggs spokeshave takes very fine shavings and is used like a smoother to finish the surface ...



Here are the completed leg blanks ..



Tomorrow I will mark out the tenons.

Regards from Perth

Derek

[John Kananis]

Derek, I'm enjoying watching along. Comment on that LV la shave. I have it and it's great... until it decides to let go of the blade. It really does excel at taking a chunk off, also on difficult grain and end grain but if you get a little too into the work or take too healthy of an amount of wood off, mine tends to pop the blade. Annoying.

[Derek Cohen]

John, here is the cutting side of the Veritas and Stanley ...



Both have mouth pieces which slide up-and-down.

The Stanley has a very secure fitting for the blade, but is fiddly to set up. The Veritas will fit securely - just! The blade needs to be made a little wider - and needs to be inserted square and evenly ... it is a lot less fiddle than the Stanley.

I would say the the Veritas does not clog quite as easily as the Stanley, but both are the same design - the shavings flow through the body - and both require frequent clearing of shavings, especially if these are on the thicker side.

Both are low angle and bevel up configurations, which makes them better for end grain and they do prefer straight grain. I like the balance of this design, which is due to their low centre of gravity. It is a reason I prefer shaves without adjusters - less mass up high.

The sole in front of the mouth should angle (3 degrees on my travishers), which enables the user to increase- or decrease the angle of attack, which changes the thickness of shaving. [edit to add: watch how you hold the angle - too much can cause the blade to dive).

If you are digging in with your Veritas, you might try a higher bevel angle (just like on the BU planes). Read the grain carefully. Change direction when indicated.

Regards from Perth

Derek

[Derek Cohen]

Especially after today, this build really feels like a step forward, a step sideways, and then a step forward again ... cha cha cha ..


I really do know where I am going, and what has to be done, even if it does not seem that way! Templates would have made the process easier.


So where are we up to? Well, it is the stage where the through mortices are made. We start with 8 legs ..





The mortices will be made with a Domino ...





Then it gets a little complicated :


1. The legs are curved.
2. The mortices are cut half way from each side, and must be aligned well to meet in the centre.
3. The Domino can cut a maximum of 24mm width. The mortices are 30mm wide (by 10mm).


I have a guide for setting up the Domino to cut a specific size mortice width. This is for a 10mm x 24mm domino. Since the legs curve, the boundary lines for the mortice angle. The boundary lines cannot be dropped down on the vertical, so ...


First set the left side centre indicator ..





.. and then the right side indicator ...





Two plunges of the Domino creates this ..





Repeat on the other side.


With all 8 legs morticed, I began to lay out the tenons.


All the legs are angled at 10 degrees towards the centre. This is prior to cutting the tenons ..


Rear leg ...





Front leg ...





Here is the mock up with the plan/drawing in the background ...





And a close up ..





A last photo for today - taken from the rear. The ears represent the stock for the tenons ...





Tomorrow the tenons will be cut, and then we can get back to shaping the seats.


Regards from Perth


Derek