Intro: Adjustable Height Formica Desk With Folding Legs (made From Crutches).
This was another one of my re-purpose and reuse projects. A worn out top of an old computer desk and a bunch of crutches I'd collected were just screaming to be made into a desk. Instead of purchasing metal hardware to attach the legs I came up with a way to attach the crutches using a few pieces of wood and the hardware that came with the crutches. This proved to be a good opportunity to experiment with wood joinery. I had quite a lot of fun making this and was surprised at the results.
I did some research into desk sizes and decided that the desk should be adjustable from 27 to 33 inches high. I came up with 27 inches by considering a comfortable height for a keyboard.
The legs can be placed in three positions; vertical, diagonal and closed. They are attached to the top using a long screw and wing nuts. The long screw and wing nuts came from where the handles attached to the crutches.
Some of the pictures create an optical illusion which makes the side rims of the desk look like they are not at 90 degrees.
I think the curves, as well as the angle of the legs causes this illusion.
Step 1: Tools and Materials
- tape measure
- cross cut saw
- jig saw
- wood chisels
- right angle
- paint brush
- four of the same sized crutches
- wood for the table top
- Hardwood for the side and leg attachment points
- piece of formica slightly larger than the top.
- wood for cross beam support (depending on the top you use)
- wood glue
- contact cement
- putty if needed
- a few screws
Step 2: Disassemble the Crutches
I have used four of the same size crutches to create the legs for this desk. Take all the wing nuts and screws out of them and remove the legs of the crutches from the arm pit pad. You can saw them off. I just bent them to the side and snapped them off.
Step 3: Add Attachment Holes to the Crutch Wood.
I had fun figuring out the best way to use the hardware I had. Since I didn't want the legs to actually look like crutches I disassembled the crutches, inverted one side and placed the sides of the crutches parallel. Doing this has consequences for the adjustable part. The adjustable part now has to be attached to the top of the crutch since it would hit the bend in the wood if I attached it on the bottom. Simply put. The part of the crutch legs that were at the armpit will now be at the floor. The inside piece of wood that was on the floor will still be on the floor.
There is a curve in the crutch. The length of wood on either side of the curve is different. I will refer to the shorter side as the top and the longer side as the bottom of the leg. (This is opposite of how the wood is used when it was a crutch)
The top of the leg will have a spacer in-between the wood supporting the table. The spacer will be made from a small piece of the adjustable section of the crutch. The spacer is so the distance between the sides is the same at the top of the leg as it is on the bottom of the leg. Use the adjustable piece of the crutch as a template to drill holes. Attach the adjustable piece to the top of the sides of the leg as shown in the picture. Add your holes. You will have a total of 3 holes
Step 4: Determine the Length of the Table Legs.
I determined how long to make the legs by searching online for desks and by measuring desks. I decided to make my table adjustable from 27 inches to 33 inches. 27 inches is a height that is comfortable for keyboards. This range worked out perfect for the hardware I had.
Note: The picture shows the crutch piece with what will be the top already cut off. I did not have a picture of measuring the crutch before then.
Step 5: Drill the Adjustment Holes
The piece of the crutch that previously served as the height adjustment will continue to serve that purpose. Since we inverted the outside wood, new adjustment holes will need to be drilled.
Attach the inner piece of the crutch to the outer pieces as shown in the picture. You will be using the inner piece as a template. Pay careful attention when doing this. Do NOT drill through every hole. The spacing of the holes on the inner piece and the outer pieces will be different. Drill every THIRD hole. The location to drill is marked by a line in the picture.
Move the inner pieces to another set of the crutches original holes and repeat the process.
The inner piece has holes every 1 inch and the outer piece has holes every 1.5 inches. This was done to work with the holes already existing on the crutch legs. I did not want holes that would be drilled too close together so I had left the spacing as it was.
Step 6: Cut and Round the Leg Pieces.
You can cut through multiple pieces at once. using a long bolt and wing nut, attach your leg pieces together. Cut the top where you have determined in previous steps. I cut the top of my leg just above the third hole but shy of where the next hole would have gone.
Cut the bottom of your desk leg where you have determined. Mine is cut 27 inches from the top.
Next you will need to cut the interior pieces.
The length of the your adjustable piece will be determined by how much you want the table to adjust. When my desk is in its lowest position the adjustable piece fits completely between the outside pieces with nothing protruding, Your desk may be different. I cut my interior piece by placing it in lowest table position (the 27 inch position).
The top of the leg will have a piece that is slightly longer than the 3 holes there. Attach the piece you will be using and then cut it off to get it exact. With all three pieces still connected together round off the ends. I used a chisel and file to do this. once you are happy with how the end looks, remove the center piece, turn it around and round that end to match the outside.
Step 7: Make the Leg Attachment Pieces
I chose to use a piece of oak I had to make the leg attachment pieces. This could have been done with a metal bracket but I wanted to use what I had around and wanted to try some joinery. I also thought it would make the desk look cooler, And it did!
I started by measuring the piece of wood I had and then determined if I could squeeze the eight pieces out of it.
You will need to create a template for one of the leg attachment pieces. I created my attachment pieces so they would be joined to both the desk top and the ends of the desk. I wrote dimensions on the one piece of wood, Hopefully you can make it out in the picture. As you may be able to tell from the picture I used the leg spacer to help me design the leg attachment point.
Once you have carefully designed the leg attachment point, cut them out and drill the holes.
The top and one side of the attachment point will be a tenon. I did not cut them at this step. I waited until I made the mortises and marked the the attachment points after that was done.
When completed with the attachment points you should have eight nearly identical pieces similar to the pictures.
Step 8: Make the Desk Ends
Cut two pieces of wood as wide as your tabletop.
Place them next to your tabletop and determine where the leg attachments will connect to them then mark those locations.
Draw a curve in the wood that you find attractive.
Cut the curve out of your wood.
Mark the location of your mortises and cut them out. Use whatever technique you are comfortable with. I was experimenting so I used a wire saw for some of them and a chisel for others.
Step 9: Create Desktop Mortises and Dove Tails.
Put your desk top upside down on a flat surface.
Place the assembled end pieces on the ends of your desk top.
Trace an outline of the piece onto the underside of the desk surface.
Mark where you want your dove tail joints and your mortises.
Cut both the dove tails and mortises.
Step 10: Match Up Leg Attachments to the Desk Ends
Using the mortises you have just created, mark the tenons on your leg attachment pieces and cut them out. I did not make full tenons. I thought the wood would get too narrow and didn't feel it was necessary to cut all four sides of the tenon.
If you are like me and need a lot of practice then mark your pieces. My pieces were hardly laser precise so each leg attachment piece was designed to fit a particular spot.
Do NOT glue the pieces yet.
Step 11: Mating the Components Together
Place your desktop upside down.
Attach the leg attachment points to the end piece.
Place this entire 'assembly' over the dovetail and mortises. Mark where to cut the matching joints on the end piece and cut out the pins and tenons.
When everything is cut out and aligns up, glue the leg attachments to the end pieces. Once this dries (I waited more than a day) glue the end assembly to the top piece.
When all the glue is dried you can do a test run with the legs. If you find the desk is not stable enough for your needs than you can add braces to the legs at this point. I think it is best to do this before attaching the formica top.
I used existing hardware to attach the legs. If you use the bolts that originally held on the handles of the crutch you may need to add threads.
Step 12: Putty and Trim
If your desktop is not a strong solid piece of wood you may need to add a
brace. It is best to do this before you paint and put a surface on the desk. I added the brace as an after thought so it is screwed onto the end pieces and into the top. You should do this before you putty so you can countersink and cover up the screws.
When all the glue is dry, fill in any gaps with putty.
Trim any places where the pins of the dovetails or the tenons stick out.
Give the desktop surface a slight sanding to roughen it up.
Step 13: Painting
Make sure the ends are cleaned of sanding dust.
Paint the ends of the table with the colour of your choice. I chose black to match the existing desktop moulding and to match the Formica.
Step 14: Attach the Formica Top
Formica can be purchased at many DIY stores. This can be expensive since you will have to buy an entire sheet. I took the dimensions of my desktop to a local company that makes counter tops and was able to buy a piece cut to size from them for much cheaper than it would cost for an entire sheet of Formica. They were happy to sell me a leftover piece from a project. When you are cutting or getting the top cut, make it slightly larger than your desktop surface; maybe a quarter to a half inch larger.
Cover the entire surface of your desktop with contact cement. Do this in a well ventilated area since contact cement really smells. Start at the edges of your desk, In case you run low on cement. I'd rather be missing glue in the middle somewhere than at an edge. The bottle you see in the picture just covered the surface. I avoided buying a larger bottle due to the expense of the cement.
As soon as your surface is covered place your Formica piece on top and press it down, working out any possible air bubbles. If you have something to press down the surface then place it on the surface and leave it there until the contact cement dries.
After the glue is dry; file the edges with a metal file, and round the corners. When this is done you may need to touch up a few spots with paint along the edge.
Step 15: Show Off and Use Your Desk!
My desk turned out to be successful. I have been using it daily for 3 months since I have finished it. I've been a little slow getting caught up on my Instructables. There is a slight bit of play in the legs but this does not make the desk unstable. It is strong enough to support my weight but if It were to regularly be used for heavier tasks I would recommend attaching the legs together and possible adding a diagonal brace to the legs. I am currently using it for my laptop and a writing desk. As the desk stands now(same as the picture) it is attractive and functional. When the desk is not needed or needs to be transported the legs are easily folded down by removing the lower bolt and wing nut.