Old Vehicle Seat Into Office Chair

My work was tossing an old UTV seat that had been used for testing and was no longer fit for use in a vehicle so I decided to give it a second life as an office chair for my shop instead of it ending up in the landfill. I am fortunate to have access to some tooling that others may not so you may need to adjust this design to fit the tools you have.

Materials:

• Seat to make into chair
• Office chair wheels (make sure 3 wheels will hold the desired weight)
• Steel tubing
• Steel plate
• Steel bar stock

Tools:

• Metal cutter (bandsaw, chop saw, angle grinder)
• Drill or drill press
• Welder
• Lathe (included option if you don't have one)

I wanted to make this a three wheel design to guarantee it would be stable given I didn't have a welding table to make sure the four legs were flat when welding and my floor isn't very flat and even either. For those that aren't aware, since three points are needed to create a plane, having just three points of contact to a surface will guarantee that item will be stable and won't wobble. The only problem with a three leg chair is that the legs need to be far enough out that the center of gravity can't move out of the triangle between the three wheels.

I also needed to be able to attach the vertical tube in the center so I needed some tubes to connect to the outer triangle that met in the center. This is where Fusion came in handy and let me play with the lengths until I got them all to meet in the center.

I first made the three outer tubes, I used 1 1/4 inch square tube because I was bale to grab some pieces pieces that we were tossing out. Anything from 1 inch to 2 inches should work and square tubing will probably be the easiest to use. Due to the length of tubes I could get, these tubes were 25 inches long and then cut at a 30 degree angle to allow all three to form a triangle.

I then had to put a hole in the ends to give me my attachment point for my wheels. The diameters of the holes depend on what you use to support the wheels. I made a piece on the lathe but a tube with the correct size center hole can work. The wheels I used needed a 0.438 inch center hole that is 1 inch deep. I drilled the holes to be 0.31 inches on one side and 0.56 inches on the other to match my wheel attachment but a through hole the size of your tube will work if using a tube instead.

I needed to make three more tubes that would attach to the outer tubes and meet in the middle to support the center tube where the seat attaches. I played with these measurements in Fusion and found that they needed to be 7.315 inches long with a 60 degree cut to all meet equally in the center.

Lastly, I made a part using the same tube to be 8 inches long to be the main post for the seat. I put 3, 3/8 inch holes in the side 2 inches from the bottom and each other to give me three height adjustments. I will use a 3/8 inch bolt to set it's heigh.

The next step is to make a plate to attach to your seat. The UTV seat I was using had a four hole pattern with an eleven inch spacing one direction and a 6 inch spacing the other. I designed a 1/8 in thick plate that would accommodate that spacing and had 3/8 inch holes for the bolts. I then added a 7 inch long one inch square tube that will slide into the vertical tube on the base. I drilled a hole 1 inch from the bottom to be used with the holes in the base to set the height.

I sed a metal bas saw to make the tubes and then drilled out the holes on a drill press. If you don't have those tools then an angle grinder and regular drill should work. As I mentioned above, since this only has three legs, it doesn't have to be perfect and it will still sit on the ground well. I then made the wheel attachment pieces on the lathe I have access to. I tried 3d printing those pieces first but they did not hold up so I had to make them out of steel.

Once all the parts are made, it is time to weld it all up and then paint it to protect the steel. I forgot to take pictures during most of these steps but hopefully the drawing and pictures I have will be enough to get you started.

Now it is time to move onto the seat attachment. For the tube, I cut and drilled it like the other pieces. I then cut a piece of sheet steel and drilled the corresponding hole patter that matched my seat hole pattern. I then welded up and painted it like the lower section. I had some extra length of the 1 inch tube and decided to weld it onto the plate to add some reinforcement.

With both parts made, it is now time to assemble it. The wheels need to be inserted into the lower section and the seat needs to be bolted on the upper section. When those parts are assembled, you can insert the upper tube into the lower tube and then insert a bolt into the hole corresponding to the seat height you want. You can always remove the bolt and change the height of the chair. You can use a hydraulic height adjuster if you want but I was trying to keep this is cheap as possible by mostly using scrap material I had access to.

Now that is is assembled, it is time to give it some use.

This design allows you to insert the chair so that the triangle point faces either forward or rearward. I tried both and found that I prefer it pointing forward but you may want to try both to see which you prefer.