Maloof Rocker - The Back Slats

There are 7 slats that form the back of the chair and a lot of steps to take them from start to about 90% done which is where I will stop until I fit them into the chair.  The cherry slab I am using for the slats had a few “challenges” when I went to do the layout.  There are knots, holes, cracks, some wild grain and the like that I had to work around.  

Slab for Slats

 Since the slats are structural elements that end up fairly thin at each end where they are attached I also need to pay attention to how the grain runs from one end to the other.  Starting with the preliminary layout I had done earlier I worked to improve the grain alignment and slats relationship to the flaws.  It did take me the better part of an hour playing around with different layouts to finally end up with one that worked.

Final Slat Layout

 Once the layout was done I used the bandsaw to rough out the slats to smaller, more manageable pieces.

Initial Slab Breakdown

From there it’s back to the bandsaw to carefully cut just slightly wide of the pencil line completing the first of several steps toward the finished slats. 

Rough Cut Slats

Next is to use disk, oscillating drum, pad, orbital sanders plus some hand sanding to clean up the bandsawn front and back surfaces.  The finished slat is 1¼” thick but the board I cut them from is just over 1¾”.  I had two choices, either run the board through planer until I got to the right thickness or cut them out at 1¾” then resaw to the correct thickness.  I opted to cut them from the full thickness board and resaw.  My reasoning is if I came upon a hidden flaw after the first round of bandsawing to shape (remember my surprise with the seat) I had about ½” of latitude to cut down from one or both sides depending on where the flaw was.  It was fortunate that I went this route as I had a couple of instances show up that needed to be addressed.  Using a marking gauge I drew a line on each slat about a sixteenth over the 1¼” final size removing the flaw or worst looking side.  The extra sixteenth is for cleaning up the bandsaw cut on the thickness sander. 

Ready to Cut to Width

It’s back to the bandsaw using a pivot point as a guide for the cut.  I think I have used the bandsaw more on this project than just about anything I have ever made.  I could have cut the pieces on the table saw but the curved slats left a lot of blade exposed at the finish of the cut plus the piece is not all that wide and I just did not feel comfortable with my fingers less than ¾” away from the blade.  Because of the curved shape my typical push blocks and sticks did not fill me with confidence.  I like my fingers and want to keep them attached.

Cutting Slats to Width

The bandsaw leaves a roughish cut that I have to clean up.   For me the easiest way is to use the thickness sander.  With it I can easily and very accurately clean up the rough surface so that it is flat and parallel to the opposite face.

Bandsaw Cut

Once run through the thickness sander I pulled out another template that I use to outline the face of the slats.  This one is made from plastic laminate because I needed it to be flexible enough to follow the slats curves.

The front of the slat where your back rests is flat.  However, the center part of the slats back is rounded on the router table using a 5/8” radius router bit to soften and visually lighten the piece.  Because of curves the grain changes direction along the cut so to reduce the chance of chipping I cut with the rotation of the router bit or “climb cutting”.   The downside is cutting this way greatly increases the possibility of losing control during the cut and getting hurt so precautions are required to reduce the risk.  I took several light cuts, kept the hand holding the board down-stream of the bit and used a large push block to keep my upstream hand back and away from the bit if things went bad.  Several passes later the roughed out rounding was done with no problem. 

Back of Slats Routed

Cutting Top of Slat to Final Width

The top and bottom of the slats are cut down to leave roughly a ½” centered section which then transitions to the thicker center back support section.  I used the table saw and a stop block to cut the straight part.  

The remainder along with the transition is cut with the bandsaw.  Because the back is rounded I clamped a block to the side to act as a flat reference surface keeping the slat square with the bandsaw blade.  The table saw leaves a nice smooth edge however the bandsaw not so much.  To clean up the rough cut and start on the finished transition I used an oscillating drum sander.

Cutting Transition

It Almost Looks Like a Chair!

There is still quite a bit of work to be done on the slats as they are fitted into the headrest and seat which comes later.  However, for now the last step on each of the 7 pieces is to inspect all the surfaces removing any machine marks, smoothing the curves and cleaning up transitions from flat surfaces to curved surfaces.   No humps, bumps, dips or irregularities allowed.  It’s mostly by feel rather than by measuring.  A pad sander, lots of hand sanding and patience does the trick.  

Once finished I clamped them roughly where they will go in the chair just to see how they looked then set aside until later.

Next up – Plugging Holes, The Headrest & Drilling Slat Installation Holes

Maloof Rocker - Glue-up and Arms

Front & Back Legs Clamped in Place

The actual gluing of front legs to the seat is straightforward.  All that’s needed is to make sure the legs are square with the seat.   A pair of clamps above and below the seat are used to make any minor adjustments for squareness.  The back legs need a bit more since side to side clamping and front to back clamping is required.  There is also a temporary spacer that is cut at 5 degrees to match the splay of the rear legs.  When that piece is clamped in place it trues up the legs to the seat so you don’t have one leg at 6 degrees and the other at 4.

The arms are next.  I started by tracing their shape from the template then cutting them out on the bandsaw leaving the end where it connects to the back leg a little long.  That joint requires a compound cut and the setup varies depending on how the angles between the seat and legs match up.

One Arm Cut & the Other Ready for Bandsawing

After cutting the arms out I made a choice of which arm was left and which was right then moved to the disk sander to smooth the outside curve of the right arm to fit into a jig.  One of the arms can have its compound cut made using the crosscut fence while the other needs to be held in the jig.

Left Arm

Right Arm

The compound cut starts out with the blade tilted to 23 degrees and the fence square to the blade.  Once the initial cut is made and I do a test fit the adjustments begin.  I tweak both the blade and the fence to get a tight joint between the arm and the leg with the arm centered over the front leg. 

Left Arm - Initial Cut

Left Arm - Fitted

The arm is attached to the front leg using a ½” dowel.  The hole in the leg for the dowel was drilled on the lathe and then the top of the leg was cut to a 13 degree angle.  Now I need to mark the exact location of the center of the hole in the arm then drill a ½” hole at 13 degrees to get a tight joint between the arm and the leg.   Marking the hole center is easier than you might expect.  I put a dowel center finder in the hole, set the arm in place, give it a whack and the center of the hole is marked.

Dowel Finder in Place

Center Point For Drilling

Now all that I have to do is drill a hole at a 13 degree angle centered on the mark.  At first I was going to just tilt the table on the drill press but when I went to loosen it I needed a 23 mm socket to fit the clamping nut.  The way the table is constructed an adjustable wrench will not fit and guess who does not own a metric socket that size?  My alternate method, which worked just fine, is a board clamped to the table at shimmed to 13 degrees.

Jig For Drilling 13 Degree Hole in Arm

Now that I had the holes I needed a ½” dowel.  My experience with dowels purchased at the big box stores are that they are not truly round and are generally a soft wood.  Since I only need 6 dowels for the whole chair and wanted them made out of hardwood I decided to make them out of leftover pieces of cherry.   First is to cut a 5/8” square piece about 5” long and turn it to just about 1/64” oversize.

Dowel Turned 1/64" Oversize

Driving Dowel Through Die

Because trying to turn a cylinder exactly a ½” in diameter is tough I took the slightly oversize piece and drove it through a piece of steel with a ½” hole in it.  The steel acts like a die and trims the dowel to just about a thousandth over ½”.  The oversize is due to the compression and springback of the wood fibers as the blank is driven through the die.  Next is to remount in the lathe and sand slightly so I have a perfect fit.  Last is to score some grooves down the side of dowel to provide an escape for any excess glue in the joint.  I really do not want to end up building a hydraulic cylinder and split the leg apart when I clamp things together.  Cut to length they are ready to use.

Finished Dowel Ready to Cut to Length

Arms and Legs Installed

Mounting the arms to the back leg is done with a 3”x #10 screw.  Preparation requires just three steps:

1.  Drill a ½” diameter countersink hole two-thirds the way through leg.  I will fill the hole with a katalox plug later.

2.  Drill pilot hole through leg and into arm.

3.  Drill clearance hole through leg.

Once that is done assembly consists of applying glue to the dowel, the arm, clamping them in place and installing the screw.

Next-up - The Back Slats

Maloof Rocker - The Legs

Now that the seat is pretty well shaped I moved on to the legs.  The front legs came first.  For some reason the dados needed to be cut just slightly deeper.  They should have fit but with such a wide cut there is a tendency for the piece to sometimes ride up a bit giving you a slightly shallow cut.  The difference was only a couple hundredths of an inch but it was enough to keep the leg from fitting.  The fix is pretty easy using a narrow plane to shave them down a bit. 

After making that adjustment a problem in the matching the curved part of the joint needed help.  I used the pencil trick to find the high spots and worked them down a little at a time until the joint fit good and tight.

Here is the front leg template, the layout and one rough cut on the bandsaw.

Next was to mount the rough cut blank on the lathe and start turning each end to a smooth taper.  This shows one end done and ready to move on to the other end.

The front legs are attached to the rockers and arms using ½” dowels.  This requires that I drill a hole 2” deep centered on each end of the leg and in-line with the leg axis.  After some thought the best way seemed to be using the lathe.  I mounted the leg in a 3 jaw chuck, the drill bit in the tailstock and used the hand wheel to run the bit in the required 2”.

Unfortunately, when I mounted the tapered leg in the 3 jaw chuck the steel jaws dented the already turned part of the leg.

Because the wood fibers were only slightly dented and not cut the solution is to use a hot iron and a wet cloth to steam the fibers.

This causes them to swell back up to their original shape.  Once dry a quick sanding to remove the raised grain and all is well.  The front legs are now ready to glue onto the seat.

All that remains is a little work on the rear legs.  I had to cut away some of the leg’s inside face to reduce the amount of material removal during the sculpting phase.  Some of the edges then get a roundover routed on them.  To make sure I routed where I needed to and not where I didn’t I marked up the pieces.  Here are my markups after routing.  As I have said before I make notes to myself all over the pieces.  More than once it has saved my bacon.

The last bit of work is to drill a ½” hole in the bottom of the rear legs for the dowel which will be used to make the connection to the rocker.  One went just fine, straight and in-line with the center of the rear leg axis.  However, the other leg did not go quite as well.   For some reason the drill drifted slightly (less than 1/8”) off the leg axis.  Only problem that causes is when I drill the hole in the rocker I will have to match that angle.  With that, I have the legs and seat ready to glue together.

Next up - Glue-up and Arms

Maloof Rocker - The Real Seat: Bandsaw and Hollowing

This week the post is fairly short. However, the time spent in hollowing out the seat and getting it to a smooth flowing surface was not.   My description and photos of the work needed are brief because I don't know of many people that would find a lot of photos of me using a scraper and hand sanding interesting.  

After letting the seat cure overnight I took the clamps off and now am ready to get started on the sculptural shaping of the seat.  Well almost, I have to cut the seat to shape with the bandsaw but before I can do that I need to add an auxiliary table to the bandsaw because the regular table is not big enough.  

Once it was in place I cut the blank to the overall shape. 

Unfortunately, while cutting the seat to shape I got a bit of a nasty surprise.  

On the outside edge near the right rear of the seat not visible and buried within the board was a knot.  I do not know if it will get cut away as the seat is sculpted, I sure hope so.  If it does not then I will have to do something with it.

Next is to get the grinder out, mount the coarse toothed carbide wheel on it and make the sawdust fly.  The grinder runs at about 11,000 rpm and really chews through the wood.  

The cherry cuts a little slower than the pine but a light touch is all that is required to do the work.

Once I had the shape roughed out I moved on to the less coarse (50 grit) disk mounted on the grinder.  This is a little less aggressive and allows for some refinement of the shape and the creation of the smooth gentle curves at the bottom of the seat.

From there it’s on to the random orbital and pad sanders using 80 grit paper to continue smoothing and refining the seat.  The transition at the edge of the seat bottom is a small radius curve not really conducive to the use of power tools.  To refine and smooth this curve I ended up using a curved scraper plus a couple of socket wrenches out of my mechanics tool set wrapped in sandpaper. 

At this point the shape of the seat is pretty well set.  From here on the finer grits are used not so much to shape as to remove scratches and prepare the surface for finishing.  I worked my way to 220 grit then stopped, for now.   You would not believe the pile of sawdust I ended up with, just on the workbench that was generated in sculpting the seat.

The next to last bit of work on the seat in this step is to route a ¾” radius on the bottom edge of three sides.  The radius is stopped short of the leg joints to allow for sculpting of the transition between the seat and the legs. 

As you may guess the final part of this step is to take a couple of hours cleaning up all the sawdust that gets EVERYWHERE!!

Next Up – The Legs

Maloof Rocker - The Real Seat: Fitting Legs & Seat Glue-up

Test Piece Joint Gap

If you remember the mockup had a problem with some gaps in the rear leg joint.  Now that I had test pieces I could work out a method of getting smooth transitions.  First attempt was to run the bits into the corner stopping there which did not work.  After close examination and some measuring I found that the over cut was a result of the different diameters for each of the bits.  The straight bit has a consistent diameter of 1” while the tapered bits diameter varies based on the depth of cut.

The fix for a smooth transition is to stop the larger diameter bit short of the interior corner.  For the top .06” did the trick and on the bottom .04” worked.  For a thickness gauge I used playing cards which are right at .01” thick each so a stack of 4 or 6 cards taped in place did the trick.  I also darkened in the initial corner radius cut with a pencil so I could gauge how the stopped cut worked for the transition.  This photo shows the pencil mark cut away in a smooth curve.  It also shows all the notes I made to myself on the piece so I use the right bits and spacers in the right places.  I am a great believer in writing on pieces to assure correct cuts.

Using Playing Cards as Spacers

At this point in the mock-up I glued the seat together.  However, this time I decided to rearrange the sequence to fit the rear legs to the rear leg joints prior to glue up.  I did this so if any hand work is needed I would not be working with the whole seat.  Also, if adjustment with a router is needed I could not do that once the seat pieces are glued together.  The rear legs and arms just happen to be cut from the same piece so the first step is to cut the legs out with the bandsaw. 

Bandsawn Rear Legs

To make sure the legs are in proper registration and in the same plane when mated to the seat I used one of the jigs I had made to cut matching faces on the legs.

Jig to Cut Rear Leg to Seat Reference Plane

More marking on each rear leg since they will be a mirrored set and I did not want to end up with two left legs!

The front legs are square to the seat so they are the same, that is no left and right.  I cut two square blanks to the length, width and thickness needed setting them aside for later.

Measuring Seat Tenon Thickness

The legs have a mortise and tenon joint with the tenon half on the seat.  My next step is to measure the width of tenon and cut the mortise just a smidge wider.  With the tenons all measuring right at .87” I decided to shoot for .88”.

With the mirrored legs and angled mortise I could not make the cut in multiple passes so I had to assemble a stack of dados to match my desired .88" cut width.  Here is what I used to make the cut: the left and right 1/8” outside blades, four 1/8” chippers, one 3/32” chipper and two .02” shims.  My test cut came out at .879”, close enough.

Dado Blades Used to Cut Seat Joints in Legs

One of the dados is at 5 degrees to match the tenon and the other is square with the mounting face.  I used the 5 degree jig to set the fence, one setup for left and another for the right leg.  For the square tenon I had to use a jig that held the mounting face square with the dado blade because the leg is curved.

Table Saw Setup to Cut a Dado

A run through the router table using a ½” radius bit matches the legs to the 1” diameter router cuts on the seat, well almost.  Because of that pesky 5 degree angle the leg does not exactly fit into the radiused corner of the rear seat joint.  This is where I get into some hand fitting.  I could see the gap but because it was inside the joint could not see where to remove material.  To find where the high spots are I use a soft pencil to mark up the inside of the joint then clamped the leg in place.  When I took it apart the high spots on the seat left pencil lead on the leg.

Pencil Mark on Top Piece Shows High Point to Trim

Now all I had to do was match the lead on the leg to where it came from on the seat, trim the joint and repeat until the leg and seat fit.

The front leg blanks are next and for now just get a dado cut on three sides and a radius routed on the two interior corners.

Finally everything is ready to glue up the seat!  Seat pieces, yep – dowels, yep – glue, yep – mallet, yep – clamps, yep – plastic so I don’t get glue all over the workbench, yep.

Ten minutes later it’s all glued together and set aside until tomorrow.

Yes, I did check to see if the outside pieces were flat and they were.

Next Up – The Real Seat: Bandsaw and Hollowing