Electric Sit Stand Desk Converter

Friends,

Having a desk job can get painful for your back. A lot of people suggested to work in a standing position rather than sitting on a chair for hours. So, I started looking for a Sit Stand Desk converter and the cheapest one available in the market was about Rs. 13k (~$200). The electric ones were cooler and cost about 21k (~$300).

Seems expensive...So why not make one..!!!

Here is my version of an Electric Sit Stand Desk Converter - Fully functional, easy to make and costs less than Rs. 3.5k (~$50). Of course the efforts you'll put in and the satisfaction is PRICELESS.

Please feel free to comment and I'll try my best to answer any questions you may have.

Enjoy..!

PS: Please take care of the following:

1. This is my first instructable, hence please excuse if I've not documented all steps in details.
2. Images should provide a better perspective. Unfortunately, I did not take pictures of everything I did, hence you may find something missing
3. Also I've not noted exact dimensions, but you should be able to figure out approximate dimensions from the pictures. You should be fine if you make your own adjustments.
4. Please read the entire instructable before attempting. Like many others, I've made mistakes and I wouldn't want you to do so. Hence choose materials wisely.
5. I'll be happy to answer any questions you may have

Supplies

Here are the materials you'll need:

1. Aluminum Extrusions (Buy good quality ones) (Better option is Mild Steel)
2. A Linear actuator (4" stroke length)
3. Laminated particle board or MDF or lightweight plywood - you could also use a drawing board or composite sheets (bakelite)
4. Gas Springs - 12"
5. Bolts and Lock nuts
6. PVC bearings - Extracted from sliding window parts
7. 12 VDC 2Amp Supply
8. Wires and wire connectors
9. A DPDT Switch

Here are the tools you'll need:

1. Electric drill and various drill bits
2. Screwdrivers
3. Power Circular saw (recommended is a Mitre saw, but i did not have one)
4. Hand Saw for metal
5. Set of files for deburring cut metal
6. Jigsaw (For shaping the board)

Step 1: Determine the Size

The size would depend on what you usually work on. I work with at least 2 monitors and this is what this instructable would concentrate on.

This desk is about 31" wide, 20" deep and 5" high, adjusts from min. 5" to about 16".

The size of the aluminum profiles should as per the above image.

Step 2: Making the Frame

This is how the entire frame would look.

In order to start making the frame, you'll need cut about 24 L-shaped brackets from an L-Shaped aluminum extrusion. Use 1x1" extrusion and cut brackets about 20mm wide. You will also need to drill holes on both sides to screw them on the other profiles.

1. Start with the base where you will use the 27" and 16" profiles to form a rectangular frame with some part of the profile protruding out of the rectangle. The internal breadth of the rectangle should be exactly 10"
2. Then start with the H-frame using the 24", 9" and 7" profiles. Using the brackets, screw them on to create the shape. The images should give you a better idea.
3. Once the H-frames are done, drill 6.5mm holes in the center and using 6 mm nut-bolts, create the scissor shaped structure.
4. Round the edges of the scissor structure, so that bearings can be installed

Step 3: Sizing and Shaping the Table-top

1. Take the particle board sheet (I've used 20 mm thick but other lighter options should be fine as long as they can hold screws) and cut them to the shape and size mentioned in the image. You can use your own shapes too - Perhaps more ergonomic
2. Use large aluminum profiles (2" x 4" rectangular) and cut them to create your own brackets on which the keyboard board would rest on. Attach it as shown
3. Invert your scissor frame on the tabletop board and make provisions using the L-brackets for the fixed ends
4. Use the other 2 pieces of profile created for bearing guide along with L-brackets to create a guide on the board

Step 4: Installing the Bearings & Rolling Guide

1. Extract the bearings from the sliding window rolling parts
2. The bearing should have a 5mm bore so that you could use M5 nuts and bolts
3. Once you have rounded the edges (note: Round only those edges that would face the ground and the ones that would touch the board on top)
4. Using M5 bolts, attached the bearing to the edges that face the right side. (Warning: I made a mistake. The image shows bearings on the bottom right and top left edges, however it should be on the bottom right and top right edges. The Edges on the left side will be fixed)
5. For the rolling guide attached to the bottom right, you will need a 6" long piece of the same profile, and cut it into 2 pieces through the longer edge (see image). You will need 4 such pieces
6. Use 2 of them and attached to the bottom right as shown
7. You will need something to keep bearing within the guide. I've used some scrap pieces of aluminum profiles and attached them to the top of the bearing on the frame, so that it does not come off when the scissor is lifted

Ultimately, I also used a long threaded rod instead of nuts for better stability.

At the end of this step, your frame should look like this, except for the bearings in the right place :)

Step 5: Installing the Gas Spring & Linear Actuator

Ideally, just the linear actuator should work and should easily be able to handle a load of 15-20 kgs. However, the wooden board (Laminated Particle board) that I used is pretty heavy and hence I had to support the actuator with gas springs. These springs not only reduce the load on the actuator, but also provides stability to the frame.

Remember, if you're using gas springs, they would need very strong supports at their ends. The aluminum profiles we used, will easily bend, if the load increases. Hence, you would notice I added wooden supports. The wood is fixed to the frame, which also provides additional rigidity to the frame.

You would also have to alter or cut some parts of the frame that will allow the gas springs to fully retract. This way the scissor lift won't interfere with the springs, when fully lowered

The Linear actuator is installed using 2 horizontal rods - 1 at the bottom center of the frame and the other at the moving portion of the H-frame (The one were with the bearings in the guide)

The images should make this clear.

You would also need to install some diagonal support (as shown in the images). The reason being, without these supports the entire table does not stay rigid/stable. You'll understand when you make it.

Step 6: The Electrical Stuff

This is the easiest part:

• Take your standard DPDT switch
• Measure the dimensions, as we will need to make a mount
• Use one of the available Aluminum L-profile and create a slot for the switch as shown in the picture
• Use connector clips or solder wires as shown in the connection diagram
• Use cable ties or cable fasteners to tie the wires at various spots in the frame. This ensures the wires do not interfere with the motion of the lift table

You're all Set..!

Step 7: Final Checks and Mods

So this was my first attempt in making this table. Works great, but I think it could get better. Here are some ideas that would make the table even more smooth and stable

1. Wood - Looks ugly though - You could use double profiles to make it stronger
2. Cutout options - These could have been better, but I was too lazy to spend the extra time in making cutouts more finished
3. Mild steel profiles instead of aluminum - Yes, I highly recommend using Mild steel profiles that should be welded and get it powder coated for a better look. This will ensure your table is sturdy, stable and you won't have to install diagonal brackets
4. Welding instead of bracket assembly - again, highly recommended
5. Linear guides instead of my makeshift bearing arrangement - There are linear guides available which will be a lot smoother compared to my arrangements
6. Diagonal braces - If you plan to use aluminum profiles and join them with screws, suggest you also make necessary provisions for diagonal brackets