Thursday, March 5, 2015

Anatomy of a Furniture Project

My retiree activities continually rotate between photography, travel, and woodworking.  I'm fortunate to have all three to keep me active!  My last big furniture project was a good challenge.  Although it looks fairly simple, it really tested my skills.  Specifically, the doors.  It is a little unnerving, after spending 40 - 50 hours to create them, to rout and chisel the final mortises for the offset knife hinges.  This process requires great precision to ensure uniform 1/16" spacing around each side of each door.  Otherwise the doors will not hang properly.  You plan, practice, and plan again.  I'm sure glass blowers encounter similar "holy crap" moments where endless hours of labor can be ruined in a heartbeat.

My daughter Stacey asked if I could build a walnut wine/stereo cabinet for her beautiful D.C. loft from a picture that she found.  She liked the idea of me documenting the entire process of building it.

When I tackle projects like this I always go through several stages:
1) excitement about building something new
2) lots of drawings and calculations to "reverse engineer" someone's beautiful design (thank heavens for algebra so I can interpolate from just the outside dimensions)
3) sudden realization that this is going to be trickier than I initially thought
4) frustration finding and buying the materials
5) total immersion in the project (to the dismay of my "abandoned" wife)
6) excitement, relief, and a bit of melancholy as I get to the final stages
7) satisfaction that I was able to pull this off

Day 1:  Shopping

American Black Walnut is prized in furniture making but it has become harder and harder to find quality wood.  All the really good logs generally go overseas or to companies that make veneer.  It took all day and visits to 5 different suppliers to find the five boards in this picture.   I wasn't able to find ANY decent 8/4 locally so I called my old supplier in Rochester, Pittsford Lumber, to ask what they had in stock.  Fortunately, they had just what I needed and, coincidentally, Claire is heading up to Rochester to visit her Mom, so she can pick it up.  This made my day!  Ka-ching:  Hardwood cost so far approximately $430.

Also on the shopping list were the other elements of the credenza; the stemware rack, the chrome and leather drawer pulls, the Soss Invisible door hinges, the the magnetic "push" catches.  It took some major sleuthing to find the Italian supplier of the drawer pulls but in the end I was successful finding everything.  Ka-ching:  Cost for hardware approximately $120.

Day 2:  The Glue-up

The top of the credenza is approximately 41" X 20",  but hardwood typically is 4 to 6 inches wide.  Also, it has rough edges.  All edges have to be jointed (made smooth and perfectly perpendicular to the face).  The wood is laid out so that adjoining boards match color and grain pattern as well as possible so that seams are barely noticeable.  Then slots are cut for "biscuits" that are used to help align the boards for glue up.   The objective is a flat panel but it's tricky because all boards have some degree of warp, cup, twist, or thickness variation.  Clamping cauls (simply 2" wide pieces of hard maple set on edge) help keep the panel flat during glue-up.  As you can see in the picture, LOTS of clamps are needed, thus my annual Christmas request for more clamps!  Glue-ups are typically a race against time, applying the glue to edges and biscuits, then trying to place all the cauls and clamps before the glue sets.  Mark Ronson / Bruno Mars'  "Uptown Funk" is the appropriate music to play during the glue up to get your blood pumping!!

Day 3: Making the top really, really flat

The clamps are off and now it's time to make the top perfectly flat and smooth.  4 steps:  scrape off remaining glue squeeze-out with a cabinet scraper.  Plane both top and bottom surface with a Jack plane and/or a Smoothing plane.  Scrape the whole surface again, sand both sides with 80, 100, and 120 grit sandpaper with a random orbit sander.  Continue sanding top side only with 150 and 180 grit sandpaper.  Wipe down the surface with mineral spirits to make sure there are no defects, glue spots, etc. showing.  I'll now set the top aside and cut it to final dimensions and finish sand it later.
Cabinet scraper
Smoothing Plane
 The smoothing plane should cut nice thin ribbons of wood.  
 Had to stop and re-hone the plane blade on waterstones to get better results
Random orbit sander
 Checking for flatness with a straight edge

Days 4, 5, 6 and beyond

The doors are clearly the most challenging part of this project and they are also the most distinguishing feature, so lots of care is required in their construction.  This is where multiple tests with scrap wood are very informative and helpful.

In my first (and I am sure not last) bonehead mistake, I sized the rails too long.  Fortunately, it's just took a little time to fix that mistake.  I would have been much more unhappy if they were too short!
Mortise and Tenon Jig

 Mortise (female) and Tenon (male)

 Door frames dry fit (not glued yet)

The last couple days have been spent experimenting.  Since I'm not working from a plan, only a picture, it's hard to tell how the 76 slats are attached to the door frame.  I needed a dead accurate process for spacing the slats and ensuring they are secure.  I used scrap lumber to duplicate the door frames and built a jig that would provide exact 1/2" spacing between slats.  I then cut some sample slats to see how they looked and how secure they would be in the frames.

This illustrates how the jig works.  A dado blade cuts an exact 1/2" groove and then the piece is moved over.  The groove that was just cut registers on a 1/2" key that is attached to the backing board.  The next cut is then made, board moved over again, etc.

 Slat samples sitting in the grooves

The slat in this pic is not the actual height  of the finished pieces, but illustrates how it fits together. The grooves increase the gluing surface and provide some support so that slats can't
twist out over time.

So after all this practice, I learned that, to have the same spacing at the top and bottom of the doors, I need stiles that are 1/2" shorter than my original plan.  Sure glad I discovered that before grooving the real pieces.  It's a bit of a pain, but not TOO much work to shorten the stiles and recut the mortises.


Claire returned from Rochester with the 8/4 walnut boards and I could not be more pleased.  These boards are from the base of a very old tree.  They are 16.5" wide which is very rare, and there is not an ounce of sapwood (very light colored new growth) on them.  They are perfectly flat with no warp, checks, splits, etc.  Absolutely prime boards with a cost to match but worth it since the slats made from them will be the centerpiece of the project.

The first step is to make a reference slat that will be used as a template for all the others.  I ripped an exact 1/2" piece from the slab and then cut the "L" shape on each end to ensure a perfect fit into the grooves on the door.  The top length is intentionally a bit long.  They'll be cut to final length, matching the width of the door stiles, after the door is fully assembled.  

Reference slat sitting in the door frame

I used a couple jigs (fortunately already made during prior projects) to help ensure repeatability.  If the bottom length is even a fraction too long or too short, gaps will show, and I hate gaps!

And here are 76 slats, each cut to exact width, depth, and length.  Now I need to add the "L" at each end (like the reference slat on top).  Then my least favorite part, sanding them to remove any saw marks and make them smooth enough for finishing.  Fortunately I used a really high quality new saw blade so sanding should be minimal, but there are 304 sides, tops, and bottoms to do!

Yay, the stemware holders, drawer pulls, and hinges arrived.  Stacey and I decided to go with an oiled bronze holder rather than chrome holders.  Here are two of the four.  They should look great against the finished walnut.

It was kind of a mind-numbing process making all the cuts on 76 slats, but they are done! 

Was wondering what creative project I could make with all of the cutoffs!

Test fit the slats into one of the doors.  Next I'll remove them all and start the sanding.

Gluing in the slats took every clamp I own (three times over)!

I intentionally cut the slats so the bottoms were a little "proud" of the door frame

Then I used a low-angle block plane to hand trim the slats to be perfectly flush with the frame

And these are the shavings from just one door!

 After final sanding, I finished the doors with 3 or 4 coats of Danish Oil.  The picture doesn't do them justice.  Very rich, deep walnut color.

As mentioned back on "Day 1", good walnut boards are hard to find.  The hardwood rating system doesn't consider sapwood a defect, but most furniture-makers don't like it because the color is so different from the heartwood.  If you can't find boards without sapwood, the only choice is to cut around it (and the knots) or try to dye/stain the sapwood (not fun).  That's why it is usually necessary to buy up to 30% more wood than the project calls for.

Rough (not planed smooth yet) lumber is cheaper but even experienced woodworkers can't tell if it will have much sapwood until it's planed.  I liken it to opening a Christmas present; you are all excited about the potential and then either disappointed or delighted after it's opened (planed).  The board above fell into the "delighted" category because it had very little sapwood on it's 7 foot length.

After a wonderful surprise visit for my birthday from all of our kids,  I got back to the project and completed the base (walnut plywood joined by tongue and groove to solid walnut edging) and the carcass (3/4" walnut plywood) of the credenza.  This was done with dados (grooves), dowels, glue, and screws.  The back of the carcass includes a 1/4" by 1/2" rabbet to house the 1/4" walnut plywood back.

To ensure perfect dowel alignment, I built a jig to guide the holes drilled into the base and sides.

 Carcass dry fit before gluing and screwing

With the doors (not hinged yet)

I finally returned to the project after our trip to Europe but, in the interest of finishing prior to visiting our daughter in California, I did minimal documentation.  I built the sub-base that goes underneath the cabinet from solid walnut.

The carcass was glued together and hardwood edging was doweled and glued to all the plywood edges.
The Soss hinges were then installed.  Having never used these before, I practiced cutting the double mortises on some scrap lumber before cutting into the doors and frame.  The great thing about these hinges is that they are invisible with the doors closed.  But, unlike Blum hinges commonly used on kitchen cabinets, they are not adjustable in any way, which means there is no margin for error when installing them.  After the hinges, I installed spring-loaded push latches to secure the doors when closed.

The drawers came next.  I planed the solid walnut faces down to 1/2" thick and joined them to solid maple sides, also 1/2" inch thick.  I used locked miters for the joinery.  Although not quite as pretty as handcut dovetails, they are equally strong for this application.  

The bases of the drawers were made from 1/4" walnut plywood.  Grooves 3/4" wide by 3/16" deep were cut into the sides of the drawers so they could hang on maple tracks screwed to the inside of the cabinet.  The tracks and drawers were waxed to make them slide perfectly smooth. 

 The chrome/leather drawer pulls were then added.
The last bit of construction was to build the wine rack from 1/2" walnut plywood.  Like the cabinet carcass, this was done with grooves to secure the vertical and horizontal pieces.  Hardwood edging was added to the plywood edges.
The top of the cabinet was secured with figure 8 tabletop fasteners and then 4 coats of Danish Oil were used to finish all surfaces.  I added my traditional brass plate to the inside of one of the drawers and took a few final pictures.  Whew!!  Time for a beer.