Maloof Rocker - Plan Problem & Finishing the Slats

While I was working on the seat to rear leg joints I noticed that the back of the seat was 3/16” short of being flush with the back of the leg while the video showed it extended beyond the back of the leg.  The problem was on both the test piece and on the actual chair as well.

Rear Leg to Seat Problem

This was going to make a flush joint a problem.  After going back and measuring the plan templates I found that there was a ¼” error in the plans.  I had a couple of ideas on how to fix but was not really happy with either.  I tried one on the test piece consisting of narrowing the leg at the joint and feathering that down the leg but felt that it detracted from the chair’s lines.  I was also concerned that I was weakening the rear leg.  The other was to create a radius between the leg and the seat similar to the front leg joint.  I sent the author a note explaining what I had found and asking for a recommendation.  

Blended Joint

He replied that at times he had the same problem and what he did was to radius the joint.   I started going down that path but part way through found that the inside line of the leg was going to be interrupted by the 3/16” radius.  More thinking and talking to myself followed before I settled on a final fix.

I started just below the arm of the chair feathering a taper toward the inside edge of the leg increasing it to 1/8” as I moved down the leg without removing any material from the outside edge.  This left the overall line of the leg unchanged when viewed from the side.  It also minimized the wood removal retaining maximum strength.  From the seat on down I reversed the taper until it was feathered back to nothing.  The roughly 1/16” left at the joint I blended into the seat.  

With that done I was glad to move onto fitting the slats to the chair.  First is to lay out the slats where they would go and deciding what order I wanted them.  The idea was to make the grain flow from one slat to the next.

Slats In Final Order

I start the installation by measuring the depth of the holes in the headrest then marking that depth on the headrest face.  This will be used to determine the length of each of the slats.  Next is to make a mark on the slats ¾” from the bottom to match the depth of the holes they go in.

Seat Depth Lines on Slats

After clamping the headrest where it will go between the legs I set the mark at the bottom of the slat even with the top of the seat. 

Slat in Place at Seat for Marking Length

With the slat in place I go to its top and use the depth mark on the headrest I made earlier to establish the slat length.  A second mark is made where the slat crosses the bottom of the headrest.  This gives me the length of the top pin.

Lines for Length of  Slat and Length of Pin

Since the seat and the headrest are both curved the length of the slats change from one to another.

All Slats Marked for Cutting and Shaping Pins

Once cut to length there is an obvious conflict in installing the slats.  The proverbial square peg in a round hole.  The ends of the slats are square and the holes in both the seat and headrest are round.   To go from a square end to a round end fitted to the holes in the seat and headrest involve a few steps.  First using a template I draw a ½” circle on the end of the slat then mark the end point for the transition from round back to square.  The shaping starts by using the pneumatic grinder and burr to rough out the pin.

End of Slat Marked for Final Shape and Initial Grinding

From there I use a couple of rasps and sandpaper to end up with a ½” diameter pin ¾” long that will fit into the previously drilled hole in the seat.  As a sizing jig for the seat I drilled a ½” hole in a piece of ¾” thick oak.  Process is to use the rasps and jig working down until the pin is flush with the bottom of the jig and tight.  Once that is done I file and sand a smooth transition between the round pin and the square slat.   

Slat Pin and Transition Done

The end that goes into the headrest is the same except the pin is almost 2” long.  Let’s see 7 slats and 2 ends with one end done equals only 13 ends to go.

Finished Slat

With the pin fitted and the transition complete I put the slat into the seat and move on to the next one.  

Three Slats in Place - Four to go

Once all the slats are fitted I do a test with the headrest and holy cow it looks sorta like a chair!

Next up – Headrest Shaping Part 1 plus Slat & Headrest Installation

Maloof Rocker - Sculpting the Arms

To me one of the most appealing items in the chair are the arms.  The way they flow from the back legs into the very organic shaped armrest and then onto the front legs.  No straight lines here!  I had laid out my reference lines for the arms when I did the rear legs so there was not really anything keeping me from starting.

Layout Lines on Arms

Chair Clamped to Lathe

Because there is a lot of material to remove first is to take the sanding disk off the 4.5” angle grinder and put the coarse carbide wheel back on it.  I set the chair on the floor, clamped it to the lathe to help keep it from moving around and gingerly started making freehand passes. 

Process is to work my way grinding down into the arm toward the reference lines along the long axis working from the outside in. 

Once the edges are ground down close to where they will end up I started to remove material from the center to marry the edge lines.  When I get to a rough shape I switch the from the coarse carbide wheel to the sanding disk to smooth out the surface and refine the shape.  After going as far as I can with the disk sander I move to the rasp and hand tools.  The idea is to get to a 90% finished shape then move on to another area.  Once all the adjoining surfaces are at the 90% level I will work to tie all of them together.

Left Arm Shaping Progression

Top of Left Arm Rough Shaping Completed

After both arm tops are 90% done I flip the chair over so I can work on the underside.  Here where the front leg joins the arm I had one more layout line to add.  It is a guide for setting the arc or fillet between the arm and the leg.  The easy way to draw a concentric circle around the leg is to take a washer and using the center hole as a guide rotate the pencil around the leg.

Adding Layout Lint to Underside of Arm

I follow the same sequence for the underside of the arm as the top except it is harder to do than the top.  With the top I have free access from all directions.  The underside has the front and back leg to work around.  Then you have the inside edge which you can’t really see because the seat is in the way and lastly you need to keep track of where the back side of the grinder is spinning.  You do not want to be working on making a cut while the grinder back end is happily chewing on one of the legs.  I know that can happen from experience on the test piece.   It may not be much more complex a shape than the top but access and the ability to see what you are doing is certainly more restricted. 

Underside of Arm Shaping in Progress

Because of the tighter curves and more restricted access I could not get to the same level of finish as I could on the top which means that I have to spend more time refining the shape with the hand tools. 

Using a rat tail and flat rasp along with other files, the pad sander loaded with 80 grit paper and finally ending up hand sanding I get my final shape.  It’s a long way from being ready to apply a finish but the form and shape are there.

Two small areas are left to be done.  First, is the inside rounded edge on the top of the arm which flows up the rear leg and transitions into a hard edge.  Sequence here is to layout edges of radius, grind with carbide burr and refine the rounded edge with rasp and sand paper.  Second is to complete the inside edge of the rear leg where it runs between the seat and the arm.  Same sequence as above; layout edges, grind, refine with rasp and sand. 

Underside of Arms with 90% of Shaping Done

From here it is more hand work taking all the different surfaces of the arm that are now at 90% cleaning up any odd bits and tying them all together.  Lots of moving the chair around looking at it from different angles and feeling the surfaces, no humps, bumps, dips or irregularities allowed.   There is one other thing, both arms need to look and more importantly feel identical when sitting in the chair.  Although I am left handed I'm not building a left handed chair.

On a side note, these last two steps involving the sculpting of the leg to seat joints and the arms were really time consuming.  I spent the better part of 3 weeks taking them from the blocky rough shapes to where they are now.  While the overall shapes are 99% done the surfaces are nowhere near smooth enough to apply a finish.  I just know there is a whole lot more sanding in my future.

Next up – Plan Problem & Finishing the Slats

Maloof Rocker - Sculpting the Legs

Front Right Leg Before Sculpting

The sculpting of the leg to seat joints are next.  I would be lying if I said that I approached this step and was not nervous.  With nearly 150 hours of work invested in this project (both test and actual chairs) the idea of taking a grinder and whacking away freehand at the joints made me more than a little apprehensive.  

To give me some guidance and consistency on shaping the curves I pulled out my old drafting French curve and used it along with some freehand drawing to add a few layout lines.  They may not be the final shape but at least I had something to start with.   

Using the 4 ½” angle grinder with the 50 grit disk I gingerly started to shape the curve.  Once again the ease and speed that this tool removes material is surprising.  I find that I can really concentrate on the shaping and the material just disappears.  Sometimes I think a little more resistance to the cutting might be helpful.  Next is to use the pneumatic die grinder with the carbide burr to work on the top and bottom concave surfaces.

Pneumatic Die Grinder

The pneumatic die grinder is also used to cut a concave arc out to create a smooth transition from the seat to the leg.  Once a rough and I mean rough shape is ground I move on to a series of sanding drums mounted in the die grinder.  The drums progress smaller in size and to finer grits as I refine and create a smooth transition at the joint. 

At a certain point I move to hand tools; rasps, files, sandpaper wrapped flat blocks or around dowels I turned to match the arcs in the joints and at last just plain old hand sanding down to 100 grit.  It takes at least a three of hours per joint from the start to get to a point where the transitions are pretty smooth, there are no humps, bumps and there just remains finish sanding.  This is almost to that point.  I still have some fine tuning to do before I call it good.  Once there I will wait to do the final sanding until the chair is a lot closer to being finished.

The rear leg to seat joint starts out as the same blocky form and the front leg.  It follows a similar procedure using the same tools as the front legs to shape smooth transitions between the pieces.

Right Rear Leg to Seat Joint Before

This is the finished work on the leg and joint below the seat.

Sculpting the rear leg to the arm joint is a little more involved.  I start the same way in shaping a smooth transition from the leg to the arm.  However, on the inside there is a detail that gives the impression of the leg flowing into the arm.

Left Rear Arm to Leg Joint

I start with grinding the seat top to rear leg joint then outlining the curve into the leg and making a smooth transition between the two.

Layout and Sculpting Tools

Once the grinding is completed it’s on to refining the shape with a varied assortment of power tools, rasps, files and sandpaper.

Here the joint is mostly finished waiting for the arms to be shaped so the two parts can be blended together.

The last little bit to do here is to clamp the headrest back into place, mark the transition and grind it close to the finished shape.  In this picture the left side is completed while the right side is just marked.  Finish shaping will come later after the headrest is glued and screwed in place.

 Next up – Sculpting the Arms

Maloof Rocker - Plugging Holes, The Headrest & Drilling Slat Installation Holes

After spending all the time on the slats it is nice to move on to something a little different.   Each of the glue joints between the legs and the seat are reinforced with a couple of 2 ½” X #10 screws.  

Drilling Angled Pilot Holes for Screws

Sequence is pretty straightforward; first a ½” forstner bit is used to drill a countersink sink hole about ½” deep, then a pilot hole for the screw and finally a clearance hole just through the leg.  The only wrinkle is the pilot and clearance holes in the front leg are angled toward the center of the seat.  With the screws arranged one over the other and the scooped out seat you want the screws to bite into the meat of the seat.  Splitting the seat or having a screw come through into the scooped out area would ruin my day!

Using a Plug Cutter in Drill Press

Once the screws are driven home I need to plug the ½” countersink holes.   There are two choices for the plugs.  I can either cut a face grain plug from the cherry which would make it nearly invisible when done or go with a contrasting wood.   Typically with this chair design a contrasting wood is used, in this case I will use katalox for the plugs and the feature strips in the rockers.  Because I wanted the maximum contrast between the cherry and the katalox I decided to use an end grain plug versus a face grain plug.  The reason being when I apply a finish the end grain will darken more than the face grain.

Next is to cut the headrest to fit between the legs.  When I pulled the earmarked piece from the stack and checked for flatness I found that it had twisted a bit and needed to be flattened.  Out came the plane only this time I used a power plane and not a hand plane.  The power plane speeds the process up a lot but if you're not careful you can overshoot and take off too much material.

Once flat I ripped to rough width and got an unpleasant surprise.  A hidden flaw showed up that was really unacceptable.  A few bad words were said.  OK, it was more than a few.

Fortunately the wood gods smiled on me and when I laid the headrest template on the piece the bad part would be cut away.

Locating the center point for the hole the slats will go into on the seat is next.  To do this requires a bit of layout.  To make sure things went as planned I did a sketch and put together a sequience that I would use to do the work. 

In case you cannot read my chicken scratching here is the short version of what I did.  First, a base line is established across the seat at the back of the legs then dividers are used to equally space points along this line and a slat center line is then drawn using these points 90 degrees to the base line.  Next to arrange the slats in an arc to fit your back graduated offsets are measured along the slat center lines.  Finally, using a punch the center point of the slat is set along this line.

Punch Marks for Centering Holes for Slats

With the headrest clamped in place the dividers are again used to establish evenly spaced points along the bottom of the headrest.  Since the legs splay outward the spacing between the points is greater at the headrest than at the seat resulting in the fan shaped appearance of the slats.   Only the center slat mounting holes are square to the seat and headrest.  All the others are at graduated angles outward from the center.  To get the appropriate reference lines on the headrest for the mounting hole angles you set one end of a straight edge on the slat seat point.  The other is set at the headrest point and a line is drawn onto the headrest establishing the centerline of the slat and its mounting hole angle.

Using a Straightedge to Establish Drill Angles for Headrest Slat Mounting Holes

With the lines are in place the ½” holes in the seat can be drilled.  The lines provide a sight line you use to establish the angle you hold the drill.  This works great in theory and on my practice piece it worked like a charm.  However, when I went to drill the actual chair a problem arose.  My arms are not long enough for me to hold the drill in place and have my head so I could sight down the line on the headrest.  I had three choices:  grow longer arms, buy a ½” drill two feet long or do something else.  I opted to do something else.  The solution turned out to be clamping a straight piece of wood onto the backrest with the edge following the reference line so that is ended just short of the back of the drill.  I added a center mark at the back of the drill and then kept that in line with the edge of the wood. 

Drilling the Slat Mounting Holes

Now I could go ahead and drill the 7 holes in the seat resetting the piece of wood for each hole at its appropriate angle.

Once the seat holes are drilled that left the holes in the headrest.  They are simpler and less stressful to drill than the seat holes.  Using the drill press and shims to match the reference line angle it was easy to drill the holes at the correct angle.

Setup for Drilling Angled Holes in Headrest

Last step is to cut the arc at the top of the headrest on the bandsaw.

Next up – Sculpting the Legs