Saturday, 23 May 2020

Making a Raised Chair Base - episode 247

I was asked to make a quick raised base to lift an armchair a few inches up off the floor. The chair needed to be tilted such that the hip was higher than the knee. I looked around the internet to see what was about for inspiration but didn't find anything that was useful. So I started designing my own. 
While I could have attached a couple of sticks to the underside of the chair and been done in no time I wanted to make it adjustable and allow for the correct angle of tilt. I also know that having a chair at the right height can also make it easier for older people to get in and out and there is a possibility that the base may become permanent even after it is no longer needed. If it does then some paint or stain can be added to make it blend in better. 
The solution was to make the legs screw into the base giving me the adjustment I want but I wanted to avoid welding anything. I think I succeeded.


Click to watch video


Problems

Sometimes problems are a good thing because I miscalculated the height and realized too late to go get new bolts for this project. Fortunately the solution was simple and gave me a much better and satisfying finish. The revised foot design is not only better looking it is simpler and mechanically more rigid. The word of the day is Serendipity.

Did you spot the problem with the base when I attached it?
I'm sure quite a few eagle eyed viewers will have spotted that my base did not line up perfectly with the existing woodwork. While I measured the top and bottom and found that the base tapered 30mm over it's length I had a nagging doubt that the angles of the existing woodwork would be the same on both sides. As it turns out I was right. I probably should have measured the angles and  used those in my drawing but such is life. If it becomes permanent then when it is removed for painting It can be fixed then. After all it is "temporary"

Last Minute Changes
As with everything there are last minute changes and as you can see in the thumbnail above I ended up removing a nut from the front foot and put it on the rear. This gave me more slope and dropped the front of the chair about 10mm. The back can be raised even higher and if the front needs to be raised more the extra nut from the rear can move to the front to lock the foot in place. The center nut on the rear is just holding the spare nut for the front.

Wooden Threads
How good are they really? I used them in a previous video and found that they work surprisingly well but I would not use them where they were holding something under tension or compression. There trick with this design is that the thread holds nothing other than the foot when the chair is lifted. Once the foot height is set the top nut is wound up to the top and gently tightened to stop it being unwound and so that the chair rests in the nut and not the wooden threads. The top washer and nut is really important to this design.

Final Thoughts
Hopefully this will give you some ideas if you find yourself needing to raise an armchair or similar for a friend or loved one. At the very least I now have an adjustable foot design I can use in the future on projects that need leveling feet. Simple to make but very effective.

Hope you are all staying safe and I will catch you next time.

Cheers
Peter

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