Raise your comfort level with this adjustable-height worktable that you can use just about anywhere.
I originally designed this adjustable-height computer table (or as I call it, my “wheely desk”) so that I could work comfortably from my girlfriend’s place in another city. I wanted a table that would be ergonomically comfortable in any seating position, with the option to wheel it out of sight when not in use.
I found it very comfortable when used with a computer in combination with a couch or easy chair in my home. Therefore, I built another one which I have been using as my main computer table ever since. I sit down on a couch or easy chair, pile pillows behind me until I’m comfortable and then pull the table and computer to me (Fig. 1).
This desk is primarily constructed of inexpensive spruce lumber from a local building supply store. Locating clean construction lumber is a bit of a challenge. I find it’s best to buy 10" wide planks, because those which come from larger trees and are usually of better quality. One 2" x 10" x 10' should provide enough material for this project if it is completely free of defects. However, given the low cost of construction lumber, it’s best to just buy extra and then cut around the inevitable defects in the wood.
You will also need a 3/4" x 6" x 6' piece of oak for the vertical adjusting slides, a 3/4" x 3" x 6' piece of oak for the trim around the top, and a 1/2" thick piece of 2' x 3' veneered plywood (maple, birch or oak will do fine).
Other materials you will need include some 3/8" bolts, four 2" casters, and a lot of wood screws. See the hardware and cut lists at the end of the article for details.
Making the legs
Cut the 3/4" x 6" x 6' oak board into four 51/2" x 16" pieces. Cut four pieces of spruce 1" x 59/16" x 161/16" . Laminate the oak to the spruce to produce a “sandwich” about 1¾" thick. It’s easier to glue the oak to a larger piece of spruce so alignment errors can be corrected by trimming back the spruce part.
After the glue has dried, use a jointer or hand plane to cut the spruce flush with the oak on one side (Fig. 2), then cut it to 5½" wide on a table saw.
The next step is to cut grooves in the legs to allow vertical adjustment of the table. You’ll cut four grooves along the length of the oak face, spaced such that another identical piece will fit neatly against the grooves. Each groove should be one-eighth the width of the leg, plus about 1/64" for slack. With our 5½" width, this comes out to 11/16" + 1/64" or about 45/64" for the width of the slot. Set your dado blade to this measurement, cut a scrap piece of oak, measure, and adjust the cut as needed (Fig. 3).
Set the dado blade to cut to a depth of 5/16", set the fence to leave 11/16" between the dado and the fence, and cut a slot in the oak face of each of the four pieces. Next move the fence to 21/16" away from the dado. Make a cut in a test piece (Fig. 4) and check its position with calipers, then cut the slots in all four pieces (Fig. 5).
Do a quick check to be sure that the pieces will fit into each other before going further. Do this as soon as possible after cutting the first two slots to catch mistakes early in the process.
When measuring for cutting the grooves, consistent spacing is very important. If you’re using a wobble dado, mark the tooth that you measure to with a permanent marker. If one of the slots is out by even 1/64", the grooves might not fit into each other. Make the next two cuts by again moving the fence away from the blade, to 37/16" and then 43/16". The last groove you cut should trim the rest of the piece away. If your cuts were accurate, putting any two pieces together should look like Fig. 6.
Using a 1/4" radius roundover bit in your router, cut the two long outside spruce edges. Do not rout the oak sides or the ends of the legs.
Attaching feet and arms
Next you’ll cut the horizontal pieces, sort of the feet and arms of the frame. The two feet are 1½" x 3½" x 21" spruce while the arms are 11/2" x 2¾" x 20". Cut a 30° bevel through about two-thirds of the thickness on the front edge of each of these pieces (Fig. 7).
Attach these arms and feet to the grooved legs with 5/8" dowels. Cut or scrape a small groove into the side of each dowel to allow the glue to escape (Fig. 8) and then cut eight 4¼" long pieces.
Cut a piece of scrap spruce, about 11/2" x 3" x 8", making sure that the edges are square and true. Cut another smaller piece of scrap wood, the same length but 1" x 2", and attach it to the larger piece as shown in Fig. 9.
Now cut a third piece of scrap 1" x 1" x 4". This piece will be used to ensure that the leg is attached 4" from the end of the table support arm, as shown in Fig. 10 (it’s the piece with the two nail holes). Use the large guide to align the leg on the table support arm and then clamp the arm and the grooved leg both to the scrap piece, as shown in Fig. 11.
Put this assembly on a drill press and drill two holes through the table support arm and into the leg as far as the drill will reach (Fig. 12). The holes should be centered in the middle of the solid (non-grooved) portion of the leg, and should be about 5/8" from either edge. Drilling the holes straight through both pieces avoids any subsequent alignment problem when joining the parts with dowels.
Now remove the table support arm from the assembly, but leave the block clamped to the leg. Unless you have a very long 5/8" drill, your initial holes were not deep enough. Realign the assembly and drill both leg holes to a depth of 2½". This is a good time to round the edges of the support arm with your roundover bit. Reaching all the inside corners with a router once it’s assembled will not be possible. Do not round the arm edges that will touch the table.
Clean any shavings from the holes, and apply glue to the end of the leg and the mating surface of the support arm. Put the piece back in place, using the block clamped to the leg and the 4" gauge as guides. Make sure to align the arm right-side up. Use a thin scrap of wood to apply glue to the inside of the hole and also to the dowel. Insert the dowel in the hole and drive it home with a mallet (Fig. 13).
Remove the block and clamps that you used to hold the pieces together while drilling and gluing. Use a longer clamp to press the T-joint firmly together (Fig. 14) and set it aside to dry.
Follow the same steps for the other leg and table support arm, making sure they are mirror images of each other. After the glue has dried, trim the dowels flush with each arm.
Now follow the same process to assemble the leg and foot pieces. These are just like the table support arm assemblies except that the feet are a bit wider. You can use the same guide block, just be very careful that you attach the legs with the grooved pattern facing the opposite way so they’ll mate with the support arm assemblies. The slots of the legs should be a mirror image of those joining the table support arms so that they will mate correctly when you put the table together.
Drilling adjustment holes
Drill holes in the legs to allow for a 3/8" height-adjustment bolt to pass through. In the legs attached to the table support arms, drill a series of holes 13/32" in diameter, 1" apart. The nearest should be 6" from the top of the T and the furthest 14" from the top of the T (Fig. 15). Drill these holes nearer to what will be the front of the table, on center, in one of the dados. Because the center of mass of the load on the table is likely to be forward of the legs, this will relieve a bit of bending load on the grooved joints.
In the legs attached to the feet, drill two holes 1½" apart from each other, one 11½" from the bottom of the foot and the other 13" from the bottom of the foot (Fig. 16). Make these a little larger, 7/16" in diameter, to allow for a bit more room, and make sure you drill them opposite the holes you just drilled in the support arm legs. By making these holes 1½" apart you can make height adjustments as small as ½" by changing which of the two holes the bolt is passed through.
Assembling the frame
Next make the stretcher that joins the feet together. This piece should be 1½" x 4" x 28". Cut away half the thickness of this piece 4" from the end. I set the fence of my table saw so that it allows me to cut 4" from the end of the piece of wood. Make a series of cuts (Fig. 17), then break away the remaining wood with a mallet (Fig. 18) and clean it out by sliding it side to side on the table saw as you slowly move it forward.
Editor’s note: If you attempt this technique, use a spacer block to keep your stock away from the fence and avoid possible kickback. The same cut can more precisely be made with a tenoning jig or on a router table.
Dry-fit the leg assemblies and stretcher with clamps (Fig. 19). Use this setup to determine the length of the apron that holds the legs together just below the tabletop (Fig. 20). It is important to measure this off your assembly, as variations accumulate, and if you just cut it to given dimensions, the pieces might not slide against each other well when the table is put together.
Cut rabbets into the ends of the apron to mate with the inside leg components. The apron should only reach to the outer edge of the inside uprights. Dry fit once again, clamp in place and measure the distance between the two support arms. Cut a 1½" x 3" piece of spruce to fit this space. This piece will be glued to the top of the apron where it will both support the top and provide an attachment point. The finished apron is shown in Fig. 21.
Drill holes for the screws to hold the tabletop to the arms and apron. Select screws to use, then drill to such a depth that the screws, when bottoming out in the holes, will not penetrate through the tabletop. With a ½" thick tabletop, if you don’t plan ahead, it’s all too easy to end up with screws poking through.
Making the tabletop
I add an L-shaped oak trim around the tabletop to bring the ½" thick plywood to about ¾" for visual appeal (Fig. 22). Cut oak strips about 1" x 3/4", two pieces just longer than 24" and two pieces just longer than 37". Put the dado set back into your table saw, stacking it to give you just over ½" of cut. Then lower the dado all the way down, and attach a piece of scrap wood to your table saw fence.
Next, set the table saw fence so that the amount of cut you would get from the dado is exactly the thickness of the plywood for the top. With the dado running raise the blade to about 1/2", so any overlap it has with the scrap piece on your fence is cut away while you do this.
Cut the trim pieces on the table saw (Fig. 23). It may help to run the piece through more than once if you have any doubt about whether it was in full contact with the fence and table along its whole length. The advantage of cutting the corner out this way is that any slippage will result in less material being cut, so running it across the saw again will fix the problem.
Glue the trim to the tabletop. Start by clamping two pieces of scrap to one edge (Fig. 24). Apply glue to both the trim and edge of the plywood, and slide the trim into place. Use wedges to push the trim against the plywood edge and then use additional clamps to hold the rim against the bottom side of the plywood (Fig. 25). Edge clamps would be really handy for this, if you happen to have lots of them. Do the same on the opposite edge of the tabletop and wait for the glue to dry.
Once the glue has dried, cut the overhanging trim even with the edge of the plywood. Cut the trim for the remaining two edges to length and cut back the underside of the trim, on its ends, just enough to clear the pieces of trim you just attached. Glue and clamp as before.
After the glue has dried, cut about ½" off each corner at 45° and gently round the new corner edges with sandpaper. Then, with a 1/4" radius round-over bit in your router, round the top and bottom edges of the tabletop. Sand smooth the inside trim edges on the bottom because they'll often be in contact with your fingers when you pull the table toward yourself.
While you have your router set up, hit the corners of all the other pieces, especially the stretcher, as this piece often ends up being used as a footrest.
Once you’ve made all the parts, it’s time to apply a finish. This is easiest to do when the table is apart. I recommend a clear, water-based latex. Don’t apply a finish to the hardwood grooves on the legs or you’ll end up cleaning them out again to get them to slide freely.
Putting it all together
Assemble the apron and the two table support arms and put this upside down on the tabletop. Move the assembly so that the table is as far forward as it will go, with the back edge of the top hitting the supports. Center it side to side and outline where the arms go with a pencil. This will come in handy if you need to disassemble and reassemble the table later.
Insert the screws and then mark their locations by lightly tapping them into the table using a screwdriver and mallet (Fig. 26).
Next, remove the assembly from the tabletop. Using the marks created from the screws as a guide, drill pilot holes for the screws. Screw the two pieces together, checking to be sure that none of the screws penetrated the top. If any did break the surface, remove them and shorten the tips of the screws a little bit on a bench grinder.
Screw the legs together with their respective stretcher, then slide this assembly onto the part attached to the tabletop. Inset 3/8" bolts and washers and secure with plastic knobs. Now attach the casters. Select the mounting positions for the back casters carefully so the screw holes do not end up hitting the screws from the stretcher.
Apply a little bit of oil or grease to the casters after mounting them — both to the wheel bearing (Fig. 27)
and to the bolt going through the swivel mechanism. I find that casters generally only come with grease in the swivel ball bearings, causing the other bearings to often squeak when moved. I use this table by pulling it up to me after I sit down, so having the casters roll freely without squeaking is important.
Customizing your desk
If you want to save a bit of time, you might consider buying a ¾" thick piece of birch plywood for the top and just sanding the edges nicely instead of putting trim around it like I did.
I use my wheely desk in combination with a narrow daybed and a pile of pillows behind me. I keep my desktop computer on a separate table and put just the monitor, keyboard and mouse on the wheely desk. You may want to build a stand to hold your CPU case, depending on how you use your desk. If you do, the best place is probably off to the side, against one of the legs. That way, it’s least likely to get kicked by the user’s legs.
The maximum height of this table, with 2" caster wheels, is 29". If you do not intend to mount casters to the bottom or you would like to be able to adjust it to countertop height, just make the uprights longer. For every 1" you make them longer, you add 2" of extra maximum height. However, when using the wheely table with an armchair or couch it’s nice to be able to set the table height to its minimum of 22".
You might want to cover the crosspiece on the back with carpet if you use it as a footrest like I do. You also might choose to countersink all the visible screws and cover them with plugs for a cleaner look.
3/8" x 16 bolts, 2" long (2)
3/8" washers (4)
3/8" x 16 plastic knobs (2)
#146912, $1.50 each, woodcraft.com
2" furniture casters (4)
#27I47, $9.99 for four, woodcraft.com
1½" #8 wood screws (approx. 30)
Matthias Wandel is a software developer from Waterloo, Ontario, who works in the high tech industry. In his spare time he pursues a variety of creative hobbies including woodworking. Learn more about him at sentex.net/~mwandel.