If you live or work in small spaces, you know how important it is to make use of the space you have. This tutorial will demonstrate how to make shelves underneath a desk or work table for those items that you don't use or need frequently, but still want to have handy.

I purchased an old solid oak drafting table that someone had made. It was incredibly well made, sturdy and strong. The top was missing and there was some minor damage here and there, but quite nice, nonetheless. I decided to make a desk out of it to take to work. I added a bookshelf on top and decided to add bookshelves underneath the desk since my work cubicle isn't what you'd call spacious and I wanted to put all of that empty space under the desk to good use.

Step 1: Design Considerations

Remember those simple bookshelves we all made ourselves without tools using cinder blocks and pine boards? I am borrowing on that idea but instead of cinder blocks to support each shelf, I am making wooden supports that fit in between each shelf. These supports work in conjunction with the legs of the desk to provide overall stability to the shelves. Extra wooden supports can be made to partition the shelves.

Because the dimensions of your desk/work table will be different than mine, you will need to make adjustments accordingly. One important thing to keep in mind is that you don't want to make the undershelves too wide or you may end up accidentally hitting your knee or foot against the shelves while seated at the desk. If you live in earthquake country, like I do, then you may want to leave enough room to take cover under your desk during the quake.... "drop, cover and hold" as they say.

Step 2: Tools and Materials

Simple hand tools and small power tools are all that are needed to create these functional undershelves.

Hand saw
Coping saw or Keyhole saw
Clamps
Screwdriver
Power drill with an assortment of bits
Spade drill bit 3/4 inch
Countersink tool or bit
Tape measure
Square

Materials

Remember, when planning your project, lumber is sold in nominal dimensions, meaning that the actual dimensions are smaller than the stated size.

Shelves:

Pine boards: 3/4 inch thick, 8 inches wide, length depends on desired shelf length.

Wooden supports:

Top and bottom plates made of pine boards 3/4 inch thick x 3 inches wide, length depends on shelf width.

Pine dowels 3/4 inch in diameter

Flathead wood screws 1 1/4 and 2 inches long

Wood glue

Metal "L" bracket, size depends on size of desk/table legs

Sand paper: medium and fine grade

Stain or paint

Step 3: Cutting the Shelves

For this project I am making three undershelves with a fourth board on top for added stability. The shelves have cut notches to fit around the desk/table legs.

Go ahead and determine how many undershelves you want, then cut the boards to your desired length. Measure the width and depth of your desk/table legs and mark your shelf boards to cut out notches that will fit around the legs. To cut a notch as shown in Photo 3, drill a hole in each corner (Photo 4) before you saw anything. Now make the two easy cuts. Finish by using a keyhole saw or coping saw to start the more difficult cut, as seen in Photo 5.

Step 4: Cutting Out the Wooden Shelf Supports Pieces

The wooden shelf supports are made from a top and bottom plate, with two dowels securely attached between the plates, as seen in Photo 1. The plates are made from two pine boards 3 inches wide and are as long as the width of the shelf (in this case 7.25 inches). The height of the wooden support will determine your shelf spacing. My undershelves have a spacing of 5, 10, and 12 inches. The spacing is measured from the upper surface of one shelf to the lower surface of the shelf above it.

I needed a total of 9 wooden shelf supports. Since each wooden shelf supports has a top and bottom plate, I cut 18 pieces of 3 inch board 7.25 inches long. These boards will attach to the shelves with screws.

Determine how many wooden shelf supports you will need and cut the top and bottom plates from 3 inch wide boards. The length of the plates will be equal to your shelf width.

Now for some math to calculate the length of the dowels. Take the overall desired height of your wooden shelf support and subtract the thickness of both plates. Because the dowels will be set into two holes or sockets that are each 1/4 of an inch deep we need to add 1/2 inch.

In this case the equations to calculate dowel lengths are:

5 inch spacing: 5 - 2 (.75) + 2 (.25) = 4 inches
10 inch spacing: 10 - 2 (.75) + 2 (.25) = 9 inches
12 inch spacing: 12 - 2 (.75) + 2 (.25) = 11 inches

You will need two 3/4 inch (diameter) dowels for each wooden shelf support. Calculate the lengths for your project and cut the dowels.

Before we assemble the wooden shelf supports, we will need to align the top and bottom plates with their location on the shelves. We will do that in the next few steps.

Step 5: Layout

For layout purposes label each location of the wooden shelf supports with a letter of the alphabet as seen in Photo 1. At each wooden shelf support location draw a center line on the face as well as on the front and back edges of the shelf as seen in Photo 2. This will be where we attach the wooden shelf support to the shelf.

Determine how many wooden shelf supports you will need and cut the top and bottom plates from 3 inch wide boards. The length of the plates will be equal to your shelf width.

Now that your top and bottom plates are cut, find the exact center of the width of each plate and mark it with a pencil. Mark the upper and lower surfaces as well as the edges as seen in Photo 3.

Step 6: Clamping and Drilling for Shelf 1

The next few steps involve drilling pilot holes through the plates and shelves so that they can all be fastened together with screws later on. Due to the shelf spacing, it is difficult to get a drill into the confined space, so it is easier to drill at this stage. The down side is that every piece must be labeled so that it can be brought back to the same location and orientation, otherwise the drill holes won't align properly.

Starting with shelf 1 ( the lowest shelf), having 3 locations with centerlines: A, B and C, as seen in Photo 1.

Take one of the plates and place it on top of the shelf at location C. Align the center of the plate with the centerline on the shelf, as seen in Photo 2. Clamp one end and then align the center marks on the other side before clamping the other end as well.

Once the plate is clamped to the shelf, flip the shelf upside down and drill 2 holes 1/2 inch from both ends and drill one hole in the center. You want to be sure to always drill from the underside of the shelf. Adjust the length of the drill bit so that it will drill through the shelf and then 3/4 of the way into the plate. You don't want to drill through the upper plate.

Countersink the 3 drill holes on the underside of the shelf.

Flip the shelf right-side up and with a pencil label the plate CFT, ( C is the location, F means that the end of the plate is facing forward and T means the plate is on top of the shelf). Once you have labeled the plate, you may remove the clamps and set the plate aside.

Accurate labeling is critical as there are many parts which must fitted, then disassembled and then reassembled. You may devise your own labeling system or use mine.

Repeat this procedure at location B and A. Label the plate at location B as BFT and the plate at location A as AFT

Step 7: Clamping and Drilling for Shelves 2 and 3

Take the next shelf up, shelf 2, and clamp one plate under the shelf and one plate on top of the shelf at location D as seen in Photo 1. Be sure to align the center marks of both plates with the centerline of location D. Flip the shelf upside-down and drill two holes 1/2 inch from each edge and one hole in the center (Photo 2). Adjust the drill bit length so that the drill bit goes completely through the lower plate and the shelf, but only 3/4 of the way through the upper plate.

Countersink the three holes in the lower plate.

Flip the shelf right-side up so that the top of the shelf is once again the upper surface and label the lower plate as DFB (D = Location D, F = front of plate is facing forward and B = bottom of shelf).

Label the the top plate as DFT (D = Location D, F = front of plate is facing forward and T= top of shelf).

Repeat this procedure at locations E and F on shelf 2 and at locations G, H and I on shelf 3. Remember to flip the shelf upside-down to drill the holes and then flip it right-side up to label each of the plates, following the same labeling rules.

Step 8: Clamping and Drilling for the Top Board

Take one of the plates and place it underneath the top board at location J. Align the center of the plate with the centerline on the shelf, as seen in Photo 1. Clamp one end and then align the center marks on the other side before clamping the other end as well.

Once the plate is clamped to the underside of the top board, flip the top board upside down and drill 2 holes 1/2 inch from both ends and drill one hole in the center. You want to be sure to always drill from the underside, in this case drilling from the plate into the top board. Adjust the length of the drill bit so that it will drill through the plate and then 3/4 of the way into the top board. You don't want to drill completely through the top board.

Countersink the 3 drill holes on the plate.

Flip the top board right-side up and with a pencil label the plate JFB, (J is the location, F means that the end of the plate is facing forward and B means the plate is on the bottom or underside of the top board).

Once you have labeled the plate, you may remove the clamps and set the plate aside.

Repeat this procedure at location K and L. Label the plate at location K as KFB and the plate at location L as LFB

Step 9: Drilling the Dowel Sockets

Now that we have most of the drilling done, we will drill the sockets in the plates.

To do this we must rearrange the plates so that they become the top and bottom plates for each wooden shelf support.

Using our labeled plates we can pair them together as follows: (the upper label represents the top plate and the label directly below it represents the bottom plate)

Shelf 3:
LFB KFB JFB
GFT HFT IFT

Shelf 2:
GFB HFB IFB
FFT EFT DFT

Shelf 1:
FFB EFB DFB
AFT BFT CFT

Photo 1 shows an illustration of the paired plates. It is important to remember that the dowel sockets will be drilled into the upper surface of the bottom plate and the lower surface of the top plate as seen in Photo 2.

A good way to keep track of the lower or upper surface is to examine the label penciled on the front end of the plates. If the letters are upside down then the lower surface is facing upward.

Another important thing is the orientation of the plates. The front facing end of the top and bottom plates must be facing the same direction, otherwise the drill holes won't align. When looking at the front ends of the plates you should see both labels and the letters of the labels should not be upside down (Photo 2).

Starting with the upper surface of the bottom plate, measure 2 inches from the front facing edge and place a pencil mark. Then measure 5 inches from the front facing edge and place a pencil mark. Both marks must be exactly centered (Photo 3). Follow this procedure to make two marks on the lower surface of the top plate.

Take an awl or nail and press into the wood at both the 2 and 5 inch marks to make a pilot hole for the spade drill bit.

Take a 3/4 inch spade drill bit and place a piece of duct tape 1/4 inch from the edge of the blade as seen in Photo 4. Use this as a guide to keep from drilling deeper than 1/4 inch. Drill two sockets in the bottom plate and two sockets in the top plate as seen in Photo 5 and 6.

Follow this procedure and drill two sockets in all of your top and bottom plates.

Step 10: Assembling the Undershelves for a Test Dry Fit

Now that all of the pieces of the wooden shelf supports are cut and drilled, it is time to temporarily put everything together and test fit. Place the dowels in the appropriate top and bottom plates to create the wooden shelf supports. The wooden shelf supports will be a little flimsy and loose fitting because we have not yet glued them together.

This is just a test fit so we won't be gluing things together or attaching anything with screws.

Lay down shelf 1 and place the 10-inch wooden shelf supports at their appropriate locations.

Lay shelf 2 on top of the wooden shelf supports. Place the 12-inch wooden shelf supports at the appropriate locations on shelf 2.

Lay shelf 3 on top of the wooden shelf supports. Place the 5-inch wooden shelf supports at the appropriate locations on shelf 3. Finally slide the top board in on top of the wooden shelf supports.

If any of the assembly seems confusing, I repeat the procedure in the next section in more detail with photos.

Everything should fit snugly. If there are any large gaps or spaces between the shelves and the wooden shelf supports, then you will need to cut new dowels at the correct length.

Step 11: Final Assembly

Now that everything has been test fitted and any corrections made, we will make the final assembly.

Step 1: Remove shelves and wooden shelf supports. Using sand paper, sand the shelves and wooden shelf supports. Don't erase the top and bottom plate labels until after the undershelves are firmly attached with screws as you will need the labels for proper placement on the shelves.

Step 2: Take the top board and clamp it in its correct position to the underside of the desk. Drill holes through the top board into the desk and countersink the holes before attaching with 1 1/4-inch screws (Photo 1).

Step 3: Take shelf 1 and, using 1 1/4-inch screws, screw the bottom plates of the 10-inch wooden shelf supports at the appropriate locations. Remember that the screws are inserted from the underside of shelf 1 as seen in Photo 2.

Step 4: Place shelf 1 in its proper place at the bottom (Photo 3). Smear wood glue on the bottom of the dowels and insert them into the sockets of the bottom plates (Photo 4) Smear glue on the tops of the dowels and place the appropriate top plates onto the dowels (Photo 5).

Note: When applying glue, work quickly so the glue doesn't harden while you are still positioning the wooden shelf supports.

Step 5: Place shelf 2 on top of the wooden shelf supports and insert 2-inch screws through the top plates below and into shelf 2. Turn the screws until they are just below the surface of shelf 2. Place the bottom plates of the 12-inch wooden shelf supports at their appropriate location on shelf 2 and continue turning the screws until they are seated and the bottom plates are securely attached (Photo 6). Smear glue on the bottoms of the dowels and place into the bottom plate sockets. Smear glue on the tops of the dowels and place the appropriate top plate onto the dowels (Photo 7).

Step 6: Lay shelf 3 on top of the wooden shelf supports below. Insert 2-inch screws from the top plate below shelf 3 and turn the screws until they are almost to the surface of shelf 3 (Photo 8). Glue together one of the 5-inch shelf supports and slide it into its proper location. Finish turning the screws below until the bottom plate is securely attached. Then take 1 1/4-inch screws and attach the top plate to the top board (Photo 9). Glue together the second 5-inch wooden shelf support and attach following the procedure just described. Lastly, glue together the third 5-inch wooden shelf support and attach as previously described.

Let the the glue dry for 24 hours before staining or painting.

Note: I am not applying glue between the shelves and the wooden shelf supports because I may someday want to move the desk and it would be easiest to remove the undershelves before moving the desk.

The undershelves are firmly attached to the desk/table through the top board which is attached to the underside of the desk/table in several locations with screws. If you wanted to attach the lower shelves to the legs, you could use "L"-shaped metal brackets as seen in Photo 10.

With my particular arrangement, the configuration of the shelf notches and with shelf 2 resting on the desk leg support, I won't need to use the metal brackets.

Step 12: Finishing Touches, Final Thoughts

You may stain or paint your undershelves or leave them unfinished. No one will really see them....they are undershelves afterall. I will probably stain mine to match the oak wood of the desk.

Yes, yes...it would have been easier to build a bookcase that fits below the desk and then just slide the whole thing under. In this case, however, I wanted the undershelves to be integral to the desk itself. The desk and undershelves support and reinforce one another.... and that is a nice model to emulate.