A few people asked about this one, so here goes. More pics to come.
I picked up a pair of FRS seats a while ago and decided that as I actually had no real use for them, I would make a desk chair for my home office space. Combined with my new desk, this was a serious win.
Materials included one 28″ desk chair base – https://www.amazon.com/Hihone-Replacement-Cylinder-Casters-Adjustable/dp/B08B7SVWCH is the one I used. You might need a shorter one, but I would not get a smaller diameter one. These seats are heavy, due to being automotive grade. I also used a 4′ section of steel L channel in 2″x1.5″. I cut this into two pieces that span the underside of the seat. I used 8 1-inch 1/4″ bolts, two 2-inch 1/4″ bolts, washers everywhere, and about 24 1/4″ nuts.
The biggest challenge with this project is getting the seat pitch correct. It’s a car seat from a sports car, so the seat base is pitched back qutie a bit. This does not work for an office chair. In addition, the seat mount on the seat base is also pitched back. To correct this, you have to suspend the front of the chair. (Pic coming soon)
If you use the seat rails (I did), you will have to drill one hole on each side to line up with the front holes in the chair mount. Take one of the pieces of L channel and mount it to the rear holes on the seat rails. Measure forward on the chair base to get the correct offset for the front mounting bar and drill the appropriate holes in the seat rails. Mount the other piece of L channel to those holes. Don’t tighten anything down hard yet.
You can remove the seat rails and just mount the actual seat if you are on the shorter side, but at 5’6″, I did not have to do this. I still have some down-space on the gas shock, too.
Now for the fun. Tip the seat over. I got a kitchen chair and put it upside-down on that to make it easier to work on. Take the chair mount off the chair base (it lifts off) and insert it under the front L channel, and over the rear L Channel. Bolt the back rail to the holes on the back side of the chair mount. Here is where it gets interesting – put the longer bolts into the front holes of the seat base and add washers and nuts Do not snug these up, they need to move around a bunch. There is enough flexibility in the steel to allow you to wiggle things around. I used 3″ bolts here, but 2″ or 2.5″ are more than enough and easier to work with. Add two more nuts and a washer and wiggle them into the front L channel. NOW, tighten them up at the chair base mount.
At this point, you are ready to set your seat pitch. Add a washer and nut to the stubs of the long bolts sticking through the front L channel. Flip the whole mess over and get your level out. Adjust the height of the front of the seat so it is comfortable and then tighten everything up. Use the jam nuts (the double nuts on “top” of the front L channel) to hold the position.
There you go. Enjoy your new desk chair. Mine is awesome!