Folding Room Divider (Christmas project 2013)

Now that Christmas is over, I can finally post an article on my big Christmas project for the year: a set of folding room dividers, sometimes called a privacy screen, for my brother in law.  I started out by making a sketchup model of one of the panels.  The entire set is composed of three panels hinged together, but I only drew one in sketchup just to verify my design and measurements.

Link to Sketchup Model

I started out by making grooves down the insides of all the pieces, just like you would for a frame and panel cabinet door or something joined with stub tenons.  I do this in 3 passes on the table saw.

After 2 passes...

All complete.

Then I set up the tablesaw to cut stub tenons for the middle two horizontal pieces.  I use a test piece to get the right fit.

Stub tenons complete.  Note that these pieces have a groove on both sides.  One side will contain the plywood panel, and the other will contain a wood strip to hold in the big canvas center panel.

The top and bottom rails are joined to the long stiles with through mortise and tenons for added strength.  I originally decided to use this joint because I was going to have the ends of the tenons protrude in a decorative way, but I ended up having to cut them off flush because they interfered with the hinging motion.

I cut these on the tablesaw by making a series of cuts across the tenon at the right depth, then paring away the waste.  I don't have a good setup for doing the vertical cheek cuts on my tablesaw, nor the skill (or equipment) to do those cuts by hand right now, so this is what I elected to do.

The tenons are left just a little extra thick for now until each is hand fit to its mortise.

The top rail needs to have a haunch cut into its tenon to allow it to fill the groove in the top of the stile.  Here is the shape shown in xray mode in sketchup.

I cut these using a handsaw, and cleaned and smoothed the cut with a chisel.

I got a little overzealous and forgot that the bottom rails didn't need this haunch; they could be full width tenons.  I had already cut the haunch in all of the top and bottom stiles before I noticed, but no harm was really done because I just adjusted my mortise design for the bottom accordingly.

Since the stiles already have a groove cut in them, and just because I wanted to get more experience, I decided to cut the mortises by hand using a chisel.  I begin by making layout marks.

First I mark how far down from the top to start the mortise with a marking gauge.

Then I make a mark and square across for the bottom boundary of the mortise.

Then I make marks to define the sides of the mortise using a marking gauge.

I begin cutting the mortises from the groove side.  Both sides have layout marks, and for a through tenon like this one cuts half the depth from each side, meeting in the middle.  I am no expert on this method, but I learned all I know about it from Paul Sellers.  Check it out for yourself: Paul Sellers' Blog

The mortise has reached half depth, time to flip over.

Then a tenon is fit to each particular mortise by thinning the tenon with a chisel and planes.  There are 4 through mortises for each of the three hinged panels, so 12 through mortise and tenons...whew.

The top and bottom panels are made from 1/4 inch plywood, cut to size on the table saw.

With the joints made and the panels ready, I last set to work to fill the groove in the bottom of the legs below the bottom panel before glue up.  I ripped down some filler pieces on the table saw.

I included this next picture just to show the surface straight from the tablesaw.  You can really see how a nicely flat and square piece of wood and a well set up tablesaw produces something that hardly even needs planing.

Next I rip the thin planks down to strips to fill the grooves.

Then some final planing to get just the right fit for each spot

And gluing them in.  I have the bottom rail just put into its mortise without glue to be sure this strip doesn't go too far up and interfere with the mortise and tenon.  It is left sticking up just a bit to be planed flush later.

Then the glue up...which I failed to capture in a picture.  Glue up time on a project this large is so hectic, and I just plain forgot.

Moving on - time to install the hinges.  I start by laying the first two panels together and clamping them in place.  Then I mark the start locations of the hinges across both pieces at the same time with a marking knife and square.

Then I lay out the size of the hinge using the hinge itself and a marking knife.

I deepen these cross grain marks with a chisel and mallet.

Then I set my little router plane to the thickness of the hinges and run it along the side to mark the depth.

 With the layout done, I remove most of the material with a chisel.

Then fine tune the depth with the router plane.

Here's the first finished hinge mortise...7 more to go.

I mark the locations to drill pilot holes for the mounting screws with a self centering punch.

Then I set up my egg beater hand drill with a small bit and stop collar to control the depth.  I often like to use my egg beater drill for small holes in place of my power drill.  It's not much slower and I feel like I have less chance of breaking those small drill bits.

Here I am laying out for the hinge joint between the second and third panel.  You can see that the stack is 3 panels wide.  I have a spacer shim cut to the size of the gap needed between the two pieces that you can see between the top panel and the second.

Next, I remove the hinges and stain each panel assembly.  I used Minwax Dark Walnut stain, and got some of the best results I've ever had staining pine.

After the stain had cured for 24 hours I began applying water bourne polyurethane.  It was too cold to do this in the shop, so I had to do it in the house, which meant I could not spray the finish.  This made the finishing very time intensive, but in the end I did achieve really nice looking results.

Last up before final assembly was installing the canvas center panels.   I start by ripping some strips the right thickness to allow both the strip and the canvas to sit in the grooves.

I cut the canvas oversized to start with.

Each strip is cut to length, planed if necessary to fit right, then tapped in with a mallet, trapping the canvas in the process.

The corners proved tricky because the canvas doubles up there 

I install the opposing top and bottom strips first.

 Then the side strips.  The strips are held in place by friction and also some 23 gauge pins driven into the groove through the strip.

Near the end of the project I was really coming down to the wire on time.  I rushed to install the strips and on one of the panel assemblies my nailgun angle wasn't right and the pins poked out the front of the wood.  I didn't have any time to take pictures at this point, but I was able to remove the offending pins.  This, of course, left some dots of exposed light colored pine that didn't match the stained area around them.  I touched these up by putting drops of stain on them with a toothpick, and then had the incredible misfortune of dripping some stain on the canvas.  At this point I just literally laughed out loud, knowing nothing else to do.  I attempted to remove the stain from the canvas using mineral spirits.  This did lighten the spots but not entirely remove them.  Feeling absolutely defeated and past out of time, I had to take the dividers on to a family gathering as these were a Christmas present.  By the time we arrived, the mineral spirits had completely dried out and left the spots less noticeable, but still present.  In the end, my brother in law elected to take the dividers in their current condition rather than have me replace the canvas panel.  He was really pleased with them I think, but I won't deny I still feel bad about letting them leave my shop in that condition.

You might be asking yourself, "Why did he include that depressing story at the end?"  I included it for two reasons.  The first is that I really should have just declared that I couldn't get them done in time at the last minute before I installed the canvas panels and gotten them delivered after Christmas.  The main reason I had the problems with the pins coming through and spilling the stain is because I was in a hurry.  The second lesson is that all woodworkers or craftspeople need the support of knowing things go terribly wrong in everyone's shop.  Something goes pretty badly wrong on nearly every project of sufficient complexity or size that ever goes through my shop - like they probably do in yours.  But all that really matters is how you repair or work around the problems.  We all have to remember that what we make, be it a gift or something for a client, is all that the end user will ever see.  They'll never know about the struggles you had making it, if you do your job right, they'll just see a beautiful finished product and assume you are a perfect craftsman in your shop doing everything right the first time!

Here's the finished product loaded into my brother-in-law's car for transport.

And here it is set up in its final home.  The stain spot is hidden nicely by his couch.