The Maloofian Cradle Challenge


2014-09-05
By Greg Niederhaus

The powers that be at interwood never cease to augment my woodworking skills. I love working with them because the job is all about woodworking machinery, but other parts of the job put me in the workshop. This time Gary asked me to choose between making a Sam Maloof baby cradle and a credenza that frankly, looked boring to me. Obviously, I chose the cradle. “Are you sure you can make that?” he asked. “For you, Boss, I can make anything”… Now I stand humbled.  I only had a vague photograph to refer to, and my first mistake was to plan my work before Googling for more pictures. This is a story about the most challenging piece I have ever embarked upon, the mistakes that I made, and the personal value I have derived from the whole fiasco. 
 
Uprights
 
The first thing to do was to shape two identical uprights roughly. Then I needed to make four feet to protrude at an angle down to the ground. I cut deep 2cm slots for my feet center pieces to slot in and meet each other at a miter, hidden inside the uprights. On either side of those pieces I needed to pack out another 2cm to make the feet the same girth as the uprights. Here I decided to thickness plane the pieces to be 2cm at one end and 3 cm at the other. That was achieved by attaching them to a sled, 1 cm packed up higher on one end. I wanted my feet to flare out to 8cm at the tips. Incorporating a dovetail, I joined all 8 pieces in place and my rough legs were complete. In the meantime, I made a cross beam that lap joined in the middle. I shaped the profile and cut 4 tenons at the ends to the shape of that profile. With that piece done, I could mark where they needed to intersect the uprights and cut those mortises. Now I had a free-standing structure, and I could commence with final shaping. Arcs and curves with minimal flat surfaces was what I was after, and eventually it came into shape. Shadows when the sun went down helped me to dial in the arcs and curves. 
 
Steam Bending
 
At first glance, I felt that Maloof had made some serious bends in very thick Walnut. So I figured I'd make a steamer.  At the recycling place I bought two electric water heaters. Inside a water heater is a large cylinder of stainless steel that holds the water. I cut the ends of them off and welded them together. That yielded a 32cm diameter tube about 8 feet long. One end has a tight fitting hatch and the other has an inlet pipe that connects to a pressure cooker. I welded in a 6” tall wall just in from the hatch to retain a bath of water and fixed a series of stainless rods to cradle my lengths of Cherry just above the water. I wanted to bend 30mm stock 6” wide into the shape of a U to form the “spine”, or center piece of the cradle. That's the piece that runs end to end and has ribs bending out from either side to meet a top surrounding rail, and extends further up to the pivot points I call “goosenecks”. In fact, I was hoping to yield an appearance of two cobras kissing. Little did I know about steam bending, and my first mistake was to use kiln dried wood. My next mistake was to think a couple of propane tanks secured to my bench would suffice as a form to bend around. My aim was to achieve two 30cm radius curves.  
 
Disaster # One
 
I didn't know you can over cook the wood.  I didn't know you want to bend towards the inside of the tree. I didn't know which grain patterns to avoid. I had no idea about the properties of lignin. That is the stuff that holds grain fibers together, like glue. The Youtube guys made it look so easy. Anyway, I bought three heavy duty gas burners and placed two under my long steam tube, and the third went under the pressure cooker. I modified it to hold maybe 20 gallons of water. I had it in my head that the longer I steam, the better. So I let the first piece steam overnight (the alarm clock reminded me to wake up and check my fluids throughout the night) and halfway through the next day. I got two guys to come and help with the bend. With all the preparation and investment in equipment, needless to say I was very nervous. I did know one thing: you have very little time to make the bend. So I hastily took out the plank and scalded my face. We had all our clamps, a rope with a synch knot, ratchet straps and pressure bars ready. Let's do it. Out of the steamer and on to the so-called form. Step one was to clamp a bar in the center between the propane tanks to hold the center of the plank level with the work table. Next, I used all my weight on one side and the other guys did the same on the other. Wow, what a struggle!  But we got both ends bent down far enough to slip the rope around them laterally and synch them down further towards each other. Then I got the strap clamp to encircle the mostly bent plank vertically. From underneath the bench I ratcheted as far as possible and managed to over bend my two curves, knowing to expect springback.  Pretty much maxed out, I handed out the beers and we all hyperventilated for a while. 
 
Off to the Big Deck Job Down South
 
I had it in my head the wood had to stay in the form for a week, to minimize springback. So the boys and I camped out down south for a couple weeks to build a massive elevated deck. Sweltering sun and working out of our element was tough, but nothing compared to this baby cradle. All I could think about at night was how the bent Cherry turned out. We came back and took it out of the form. What a disappointment. The split out was so severe that gluing it back in place proved too ugly to be acceptable. I suppose I could have veneered over it and that would have sufficed. After all, the bends were underneath the cradle and nobody would have known. But it didn't cross my mind. For attempt number two, I made a form that sat flat on the bench and had a series of holes for dowels to retain the plank as we muscled it into place. It seemed to work. Back down south for a week to keep wrestling twisted wet  16 foot lengths of decking into place. Lucky for me, I can perform most of my tasks for interwood via the internet.
 
Spine success
 
After 4 tries I decided to use three 10mm plies of steamed Cherry. Bent in the form together successfully and 3 tanks of propane later, I laminated them and now had a basis to build to. Here is where I thought Maloof had bent thick Walnut to shape the head and foot of the cradle. Wrong. I discovered later he had shaped the curves out of two huge chunks to achieve his contours. And the radius of the curves was much less than I thought I needed to achieve. I decided to pre-cut a curve into 4 pieces of Walnut so they would match the spine when bent. A piece of bendy ply gave me the curve I thought I needed, and I made those cuts at an angle on the bandsaw. No way, that did not work. Then I looked up barrel making and length by length, hand planed my edges to join with biscuits. With those finally done, all I had to do was cut the curves to match my cradle spine and join them. That done, the geometry of the curves grew and a lot of effort and wood were wasted. Nothing matched up.  So we went back down south for the other job.
 
New Approach 
 
I went and bought a load of 65mm thick rough milled Walnut. Once planed flat, it came to 60mm. I had a custom shaper bit made to start my internal concave curves, and layer by layer, I traced the arc of my Cherry spine to the Walnut, bandsawed that arc at an angle, ran them through the shaper and laminated them to the spine. I burned out 2 routers because the weight of the bit was too much of a shock to a machine that suddenly jumps to 24,000 rpm. I bought an adjustable speed stepless router and found that 8000 rpm does the job better if you feed slowly. Dad taught me that. I repeated layer by layer until the curve of the bit was not steep enough. Then it came down to material removal. I used grinders with 40 grit discs, sand flaps on custom built drill attachments; all sorts of sanders to get me as close to the inside of an eggshell as mechanically possible. It boiled down to elbow grease, and you can't buy that at the hardware store.  The outside was easy. A belt sander and random orbital got me the smoothness of an eggshell. Now we got to figure out the ribs. Another headache commences!
 
Ribs
 
I thought that if I used bendy ply to trace my ideal rib shapes before bending that I was smart. Wrong. I joined the Woodenboat Forum. Here is where the senior members gave me, this junior member, some great advice. First of all, nobody advocated bending kiln dried Cherry or any other species because the moisture content goes down to 7%. You want 15-23% moisture in air-dried timber like Oak or Ash. The straighter the grain the better. Next, you want a stainless steel backer strip with stops at each end that keep the wood from stretching and breaking out. If the original length of the piece is 61cm like mine, you want to measure your bent outer diameter at 61 cm. One man said to leave 3mm slack, but no more. The point is to compress the inside of the board, not stretch the outside. Finally, one member said that in his territory, he can't buy air dried timber. It's all kiln dried, and he does bend Cherry. OK, I found hope!
 
Getting Smarter, But not Enough
 
With my bendy ply, I made mockups of each individual rib, including the tenons on both ends. I matched them to the outer 61cm dimension. Each rib meets the spine at a slight angle, so I pre-formed each piece of Cherry to match the individual mockups. Each tapered widthwise from 7cm at the bottom to 4cm at the top. Thickness where they meet the spine is 30mm, and tapers to 15mm at the point they meet the rail.  By now I had made a new form with a steel backer and stops at each end, and I bought a come-along capable of pulling 1.6 tons of force. Chains secured below and running up and over my contraption hooked to the come-along at the other end of the workbench. I learned that you want to steam at 100 degrees Celsius for an hour per inch of thickness. I made a smaller steamer to save on propane costs. Once steamed, I put 4 ribs in my form flat to the pre-determined angles and tight against the top retainer. Here we go. I cranked that sucker down and around the form. I believe that most of the 1.6 tons of force was applied. Maxed out, I used a leverage bar and pipe clamp to grab a 2” by 6” rail under my bench to over-bend the ribs a bit. Result… 
 
More Lessons Learned
 
What came out of my ingenious contraption seemed like successful ribs. I put them in a drying jig and did 4 more. Upon further examination, I discovered slight split out where I had pre-cut my tenons. The lesson here is to shape the wood after it's been bent, because the surrounding grain fibers stabilize the piece as it bends. Remove any wood and you lose that support under the stress. Still, I tried to fit the pieces in. By now, I had made and fit my top rail in. That was a mistake. My bottom tenons fit in well, but nothing matched up at the rail, and those tenons had zero intention of cooperating. With all my cursing done, I went back to the drawing board. The Forum guys were right again. Bend first, shape later! Back at the lumber supplier, I bought another load of Cherry. By the time I pulled off those ribs, my yard was full of failed rib attempts. I estimate 60 bends got me the 8 that I needed. And where they meet the rail, I used lap joints. 
 
Augmenting the Rail
 
I wanted a half-half combination of Walnut and Cherry. Maloof liked those species. So far, Walnut had dominated my cradle. So I decided to thicken my rail with 10mm of Cherry inside and out, as well as along the top. I had originally meant to build up layers of thick veneer and build it like a skateboard, but veneer in Taiwan is 0.2mm thin. I found an importer of American veneer 1mm thick. Super expensive, I didn't care anymore. Ready to hand them US$450 to get the amount I needed, they said I had to wait 4 months due to a shortage of supply. I depleted my arsenal of curse words, and still had to hide those unsightly lap joints. Running low on Cherry, I re-sawed and thicknessed quadruple the amount I thought I needed. Grain choice was narrowing.  The situation required two bends per piece, but they were compound bends. That meant bending 12” wide by 5 foot lengths. I had the local sheet metal place shear a backer strip with stainless steel and break the ends to 90 degrees. That ensured no stretching. The first piece came out of the steamer and actually succeeded with the help of 3” throat Vice Grips with wide pivoting pressure plates. But after that, each piece failed. I was forced to pre-bend the rest in my come-along contraption, and re-steam them one by one in the drying form. I could only afford to buy 12 of those Vice Grips, so I did one piece per day. Once clamped to the compound bends and dry, I could then glue them in place after pre-shaping them. So I am admitting to piecing a so-called “rail” together with 20 pieces of Cherry. Yes, in spots I got some splits, and I was certainly not pleased with the multiple join lines. 
 
Compromise Solution
 
OK. The veneer people do have enough 1mm thick veneer to suit my needs now. My rail is bulked out with solid Cherry, and solid veneer laminated onto solid wood technically still amounts to a solid wood piece that has no composites. It certainly has no secret screws, but I did use bearings and short axles at the two pivots where it swings at the cobra kiss. I want my stuff to me worth millions when I am dead, if you get what I mean. So it has to last. 
 
Details, Drama and a Wrap
 
At this point I am a year into this project, subsisting on other short jobs in between. Those periods gave me time to reflect, draw ideas out and muster more endurance. Every day I woke up thinking about the sanding ahead of me. I started having panic attacks. Gary told me to abandon the project, yet he would pay me anyway. I broke down, me, the arrogant guy who thought he could build anything. I explained that the job had become the purpose of my life's value, literally. I begged him to let me finish. And so, I carefully veneered my rail, carefully trimmed it all to look uniform, and commenced with endless sanding and shaping. The evening hours and shadows gave me the perspective to fine-stream my lines, curves and slopes. I also sunk skid pads 15mm into the feet of the toughest end grain I could salvage from the scrap heap. If you weigh the cradle, I estimate the weight of the scrap to be ten-fold. Humidity is a challenge in Taiwan when you are spraying outdoors. So are mosquitoes. I work outside, no controlled environment. My imported brands of lacquer tended to bubble and fog over during this August of rain and wet air. They also dry slowly. I found a locally made brand that cooperates, self settles and dries fast. Oil and hot wax is usually my preference, but the lingering scent is not good for a baby. Turns out, Gary is expecting a grandchild, so this thing is not a showpiece, like I thought. When I posted a shot of Lacquer coat number one, Gary posted a tribute to me on FB, from which came 54 “likes” from Chinese names I do not know, and many comments. I am absolutely delighted. Wait till the last coat goes on, I deliver and come home to a Doberman who has reclaimed his workbench. I will be going through withdrawals from an addiction that has transformed the approach I take to wood. 
 
If I have to do it Again
 
I would do like the guys in Alaska who don't have a giant lathe. Laminate a huge block of walnut and jack up my truck. Bolt the block of Walnut to the drive wheel, use a cinderblock as a tool rest, and get my man James to rev the engine. Lathe out a bowl and sand it perfectly while spinning. Take it off the truck, cut it into quarters, and start building a cradle. That would have saved me loads of money in tooling, material removal and elbow grease hours. That operation would take 2 days. This last time, I spent week upon week. It's a blur, to be honest. 
 
Thanks
 
For a year I have been saying in the Editor's Note of interwood magazine, that this project would be done “next month”. My excuses got thinner and thinner. Thank you, readers, for your patience and interest. I thank the friends on Facebook who constantly encouraged me, Quincy and James with the bending muscle, Al James who is the cabinet builder from England who inspired me to go with joinery twenty years ago and advised me as I went, as well as the Woodenboat Forum veterans' advice. Lastly, Gary Liao. He is the closest thing I have next to my own father, Don Niederhaus, as an honorable man and friend who appreciates, forgives and encourages me. 
 
Now What?
 
I have no idea. Time to clean up and hire a truck to take away the buildup of trash and get this place workable again! Thanks for reading!
 
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