Expert: Mark H. Miller - 4/11/2010

Question
Greetings,

I am in the process of building 2 morris chairs.  The chairs have been built and I am ready to consider the seat and back cushions.  For the seat cushions, I am considering using no-sag springs.  I have 1 cushion frame constructed.   I am using 1.5" wide x .75 thick poplar for the frame,doweled and glued, with supports in the corners.  What is the correct way to install the no-sag springs; distance between springs, do I stretch the springs, do I tie the springs? Is forming the ends of the springs necessary?

Is the frame I have built adequate to support the springs?  Are there any standards or rule of thumb?(I can also sit on the springs and see if it breaks)

Your help will be much appreciated.

jp

Answer
Greetings,

I am using 1.5" wide x .75 thick poplar for the frame,doweled and glued, with supports in the corners.
         Even so, the frame will break,   there just isn't enough wood, can you strengthen the frame by adding another frame inside to make it 1.5 high X 2" wide.

What is the correct way to install the no-sag springs;
         The usually go front to back but can just as well go side to side, what-ever gives you the largest number of springs.
         
distance between springs,
         No less than 2" to a side rail and no less than 3" between springs 4" on center.
          
do I stretch the springs,
         Yes, they should be cut about 3" short of the distance to travel enough so that the surface is flat when the spring is pulled in place,  make certain you completely nail a spring down at the far end away from you, then wrap a strong twine around the spring close to you and pull the spring toward you, hook it on and if it is tight and flat close the clip and nail it down.  Doing this is very dangerous be careful.
         

do I tie the springs?
        That is recommended but not necessary, look at my answer from a few weeks ago on how to make the seat firmer, using rubber bands is better than tying the springs.

Is forming the ends of the springs necessary?
        Yes, absolutely, make certain there is a kink or bend at the end of the loop that is nailed down, otherwise the spring will work it's way out of the clip over time.  The reason for the form is so that the spring will stay in place.  A spring should be cut in the center of a loop that will give you a hook,  if you then form that hook fine,  if not just leave it, that will prevent the spring from coming out.


Is the frame I have built adequate to support the springs?  
         No,  not nearly, you need more wood,  as I wrote above,  I think your frame will break.

Are there any standards or rule of thumb?(I can also sit on the springs and see if it breaks)
         Yes, when you are done push down on the springs and they should not go down more than 6 inches,  if they do you should firm them up - either by cutting them shorter to get more pull or by adding the rubber bands I wrote about a few weeks ago.  
         Yes, it is fine to sit on the springs with some padding material to verify that they properly support the weight of your body.  

          Make certain that the burlap or covering that goes directly over your springs is loose and not tight so that it can move down with the springs as you sit on the chair.

          I hope this helps.  I think you are on the right track, and that all you needed were these pointer to confirm.  The only concern I have is that your frame does not have enough wood.

         Please don't hesitate to contact me if you need further pointers.  Good luck.

Mark Miller.

Your help will be much appreciated.

jp