Bar Stool Trio in Sipo Mahogany

 

Design Elements

Long-time friends and neighbors Steve and Nicky were the first to greet us when we finally moved in to our Sea Ranch home.  They were always very supportive of my furniture and recently asked me to build three bar stools for their beautiful home on the bluff.  They decided on mahogany and are still contemplating the seat top material, most likely leather.

After some discussion about size and basic style, we settled on the following design.

Sipo Mahogany Stool-2015 - two-tone step 14x17

Sipo Mahogany Stool-2015 – two-tone step 14×17

This is a variation of some stools I built previously for another client and Steve and Nicky both liked the design, but didn’t want a back rail.  For the wood I selected Sipo Mahogany, an African mahogany that has been very popular in Europe for quite some time, and is just starting to gain popularity here in the US.  The “Original” mahagony or Cuban Mahogany is nearly impossible to get and its long-time replacement, Honduran or Brazilian mahogany, is getting more difficult to get especially from FSC (Forestry Stewardship Council) wholesalers.  Sipo mahogany has a similar density as Honduran and has much the same workability characteristics as Honduran mahogany and similar grain and color, although Sipo is a little more brownish red but ages to a nice deep rich ruddy color.  I also chose Wenge as a nice accent piece for the foot rail tops because it’s very hard and can easily be re-oiled to cover any scuffs or scratches.

PGW 6/3/15

Construction Details: Dimensioning the Pieces

All the pieces for the legs were taken from one 8/4 piece of wood, and all the horizontal rails were taken from one piece of 4/4 wood.  Whenever possible, I strive to use one board for each type of component for a piece.  This helps to minimize the variation in grain and especially color that exists between boards.  Before I do any cuts, I lay out on each board exactly where the cuts will come from and those sections of the boards are distinctly marked so the final pieces can be kept together.  That way, for example, the two back legs of a stool will have been from adjacent cuts from the same board.  This takes a little time and effort, but the finished product is worth it.  These two components will match well in color and grain in the finished piece.  And speaking of pieces, the following image shows all the pieces for all three stools laid out on the workbench.  I don’t know why, but I just love these pictures of all the components laid out together…go figure.  Next comes the layout lines for each of the mortises and tenons.

Bar Stool components

Bar Stool Components

 

PGW 6/5/15

Okay, now I finally got my shipment of Wenge for the top of the foot rails.   I cut them to size and glued them to the 1 ½” Mahogany blank foot rests that I already cut.  I then trimmed the ends to length and did some rough de-gluing along the joints so I could begin the process of cutting the mortises and tenons on the appropriate pieces.  After all the M&Ts are cut and fitted, I’ll go back to the foot rests and chamfer the top front edges of the wenge as their final shape for the stools.  But for now, here’s what the foot rests look like pre-tenon.

Footrests for bar stools

Footrests for bar stools

 

PGW 6/11/15

 

Construction Details:  Mortises and Tenons

Now with all the individual pieces cut and sizeded it’s time to move on to the joinery portion of our project.  Mortise and tenon joinery has been the hallmark of fine furniture making for over a century.  The joints are strong and, if fit correctly, will last a lifetime.

I cut all the mortises first because I find it easier to fit the tenons to the mortise than the other way around.  Before I do any mortising, I first have to lay out all the cut lines on each leg.  Each mortise is ½” wide and 1 ¼” deep and positioned to leave a 1/8” reveal on the outer edge.  The footrest rails were inset an additional 1/8” back from the outer edge to make for a stronger joint in order to support the weight of a person’s feet resting on the rail.  The image below shows the mortises being cut using a mortising machine with a ½” square mortising bit.  These mortises still need to be cleaned up with chisel to square all the corners at the bottom of each mortise.

Mortising Machine with 1/2" bit

Mortising Machine with 1/2″ bit

Next we move to the table saw and a tenoning jig to cut the tenons on all the rails.  All the shoulders are cut first and then the tenoning jig comes in to cut the cheeks.  Once you have the jig set up using some spare blanks, it makes swift work of the remaining tenons for the three stools.  The image below shows the tenoning jig with a rail set to be cut.

Tenoning Jig Ready to Cut

Tenoning Jig Ready to Cut

With all the mortises and tenons cut (see below) I can now move on to matching each mortise with a particular tenon.  Theoretically, the M&Ts should all be interchangeable, but I’ve found over the years that due to minor variations in cuts matching each individual joint makes for a better overall fit in the end.  And, a good fit is essential for this joint to provide the structural soundness to hold the stool together…year after year after year.

Pieces Parts

Pieces Parts

 

PGW  6/21/15

 

Matching Mortises and Tenons and Dry Fitting

Once all the M&Ts have been cut, I sanded the legs to remove all the layout lines and saw marks.  I do this before I fit all the M&Ts because rough sanding might alter the fit around the mortises, so I’d rather sand first and fit after.  Once the sanding is complete I use an extra blank tenon to make sure all the mortises are ready for matching with its tenon mate.  The next two images show a tenon being tested for basic fit and how each specific tenon is marked for its particular mortise.  The joint should be tight and flush on all surfaces.  If you can fit a piece of paper between the shoulder of the tenon and the leg, then you’re not done.

Fitting the M&T

Fitting the M&T

Matching the M&T

Matching the M&T

Now it’s just a matter of matching and fitting each M&T until the stool is done.  The following image shows one stool dry fit and assembled.  Just two more stools to go and then I’ll disassemble them and cut the curves on the upper rails and bevel the top front edge of the wenge foot rests.  It’s a process.

Dry Fit

Dry Fit

 

PGW  6/28/15

Sanding and Glue-up

Once the curves on the upper rails are completed, and the bevel cut on the foot rests, sanding can begin.  Before glue-up I’ll sand each piece to #220 grit including rounding over the hard edges.  With the sanding completed it’s now time for glue-up, which I’ll have to do in stages.  First I’ll glue up the front and back sections as shown in the image below.

Front and Back Sections in the Clamps

Front and Back Sections in the Clamps

Once all the front and back sections are done then it’s time to complete the gluing of each stool by attaching the sides.  This can be a bit of a circus in a one-person shop but I plan it all out in advance so I keep the panic to a minimum.  Remember, each mortise has a specific tenon with which it matches.  The next image shows one stool fully clamped.

Glue-up Complete

Glue-up Complete

After the stools sit over night in the clamps their ready to be set free, and then the de-gluing can commence.  It’s virtually impossible to do a glue-up without getting some glue on the surface, and this glue has to be removed prior to applying finish.  This is actually a nice quiet time in the shop (except for my music) and I take my time to de-glue every surface and joint.  Some sharp skew chisels and #220 grit sand paper are usually all I need.

The image below shows all three stools after de-gluing.

Ready for Further Sanding

Ready for Further Sanding

The next step in the process is to add the wenge pegs to each joint to further strengthen the whole structure.  I’ll also add some corner bracing to each of the interior top corners where the top rails join with the leg posts.  After that, it’s final sanding to #400 grit.

PGW 7/26/15

 

Pinning the Joints

The mortise and tenon joint is extremely strong but like most things in woodworking there are always trade-offs involved in making any joint.  While the tenon is a structurally sound joint component, the mortise does involve removing some amount of wood from a major structural component.  If done correctly the glue applied to a joint can often be stronger than the wood it replaced, but over time glue can fail, especially in a piece like a stool which puts every joint under pressure due to a persons weight and rotational forces on the joints from uneven floors.  To compensate for this I usually pin the joints by countersinking a wood screw through the tenon.  The counter-bored hole is then plugged, in this case, with a wenge plug I made using a special plug-cutting drill bit.  The image below shows the excess plug being sawed off using a flush-cut trim saw.

Cutting off the excess plug

Cutting off the excess plug

I like to tape over the hole so I minimize any damage to the wood surface around the hole from the sawing.  Once I saw off the excess plug I remove the tape and trim the remaining plug using a skew chisel, as shown below.

Chiseling off the remainder of the plug

Chiseling off the remainder of the plug

 

Finally the plug is sanded with a #220 grit sanding block to complete the pinning.  The image below shows a pair of adjoining pinned joints.  You’ll notice that the pins are not centered on the leg, but rather closer to the center part of the tenon beneath.   Also I offset adjoining pins so the screws can overlap each other within the mortise.   In this case, I also chose to use surface grain wenge so the grain is visible in the pins.  I could have use end grain for the pins which would have been more uniform and darker, but I wanted even this subtle grain effect to match the wenge on the foot rests.

Finished Pinned Joint

Finished Pinned Joint

 

Now its on to the interior corner brackets…

PGW:  7/29/15

 

Bracing the Corners

The last step before I do the final sanding and apply the finish is to brace all four corners at the top of each stool.  In addition to adding an extra layer of strength to the overall structure of the stool, it also provides a platform through which to attach the seat to the stool.  I’ll drill a hole in the center of each brace so I can attach the seat frame to the stool using screws.  The corner bracing can be seen in the image below.

Stool with Corner bracing

Stool with Corner bracing

PGW 7/31/15

Finishing

With the joinery and sanding complete it’s now time to move on to the final finishing.  I like to use a classic hand-rubbed oil-varnish finish on pieces that aren’t subject to a lot of abuse, like a table-top.  I’ve used this finish for decades and I mix it myself using 50% semi-gloss urethane, 25% pure Tung oil and 25% polymerized linseed oil.  Unlike polyurethane, this is not a “build” type of finish.  I’ll put on 7 – 8 coats of finish, wiping off each coat about an hour after being applied.  The oils in this mixture help the finish to soak deeply into the wood, rather than just lay on the surface.  I like this finish because it accentuates the grain and texture of the wood rather than covering it.  Sam Maloof used this finish on all his famous rockers and chairs.  After this finish is applied, I finish off the surface with two coats of an oil-beeswax mix which imparts a beautiful luster to the wood (Also a Sam Maloof favorite).  This finish is hand rubbed into the prior finish and buffed out with a cotton cloth to bring out the luster.  The images below show the finished pieces, focusing on the joinery.  Notice that you can see the grain and texture of the wood in all its glory.  I love this finish!

Finish Complete

Finish Complete

Lower Stretchers Finished

Lower Stretchers Finished

PGW  8/19/15

 

Upholstery

When I started woodworking almost 30 years ago I never thought of having to learn upholstery.  Over the years I’ve made many upholstered seats and I have to say that I’ve always enjoyed the process.  Upholstery is low tech by today’s standards, and other than the addition of high-density (HD) foams, the techniques and tools have changed little in the last 100 years.  Jute webbing, web stretchers, upholstery hammers, and those classic little black tacks are all still the mainstay of the present-day upholsterer.  In addition, if you’re new to woodworking you better learn upholstery because good upholsterers are few and far between these days.  It seems like it’s a rapidly vanishing art.

For these stools I want a low profile seat so I chose a half inch wood frame, a 1” HD foam seat over a smaller ½” HD foam underlayment to help form the crown.  I’ll show pictures of this later.  I’ve completed the installation of the webbing (3 1/2inch wide) and the muslin over-topping, which protects the foam from being abraded by the course webbing underneath.  The three images below show the webbing installation and the finished muslin panel over the webbing.

Webbing being stretched and tacked

Webbing being stretched and tacked

Webbing installed

Webbing installed

Muslin Panel over the webbing and the bottom view of the frame

Muslin Panel over the webbing and the bottom view of the frame

 

PGW  8/23/15

 

Shaping The Seat

After the webbing has been installed and covered with muslin, we move on to the foam and shaping the overall seat.  I start with a piece of 1″ HD foam (1/2″ larger all around than the frame) over a smaller (by 2.5″ all around) piece of 1/2″ HD foam, as shown in the following image.  This image also shows the fabric flaps applied to the surface of the foam using “Fabri-Tac” glue.  This foam sandwich is then placed on the frame with the 1/2″ foam facing down;  this smaller piece helps form the crown in the seat once the overlying fabric and leather is applied and stretched over the frame.

Foam Seat before shaping

Foam Seat before shaping: showing view of the seat bottom

 

The following image shows the top side of the foam seat with the fabric flaps.

Top side of foam seat with fabric flaps

Top side of foam seat with fabric flaps

 

The next image shows the seat with a layer of muslin stretched over the foam and attached to the underside of the frame.  The flaps are first tacked down on the underside of the frame to initially attach the foam to the frame.

The seat is now formed with the muslin fabric

The seat is now formed with the muslin fabric

Now it’s on to the leather.  The image below shows the leather as it came from the supplier.  In this case the leather was chosen and supplied by the client and a half-hide provided enough material for all three stools.

One half hide of fine leather ready for cutting

One half hide of fine leather ready for cutting

The leather was cut and fastened to the underside of the seat frames in the same manner as the muslin overlay.  I used a pneumatic upholstery stapler for all the material.  After the leather was installed, I stapled a black cloth panel to the underside of the seat frame to finish off the seat construction.   The images below shows the completed stools.

Three Stools in Sipo Mahogany, Wenge and Leather

Three Stools in Sipo Mahogany, Wenge and Leather

Finished Stool

Finished Stool

 

…And in their new home…

In their New Home

In their New Home

PGW  8/28/15

 

 

One Response to Bar Stool Trio in Sipo Mahogany

  1. Jim Kirby says:

    Nice job Phil. When will the cable TV crew arrive? Look out Norm Abram.

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