I'm going to assume that anyone attempting this project has basic woodworking skills and is familiar with power tools, so this won't be a woodshop class. :o)
I will be presenting a flexible idea that can be modified rather than absolute plans... please feel free to experiment and play... but don't get locked into a rigid perspective that there's only one way to do it. :o)
The pictures are pretty much self-explanatory, with last pic showing the two frames nested together.
Step 1: Things You Will Need...
150' (minimum) paracord
48" heavy 1" nylon webbing (from REI)
36" of shock-cord (from REI)
1 pc) 3/4" thick oak (or other hardwood) board at least 6" wide x 60" long
30) 2.5" to 3" deck screws
12) 5/8" pan head screws
4) 3/4" dia. screw-on rubber feet with 1" mounting screws
stain & poly to taste
pencil type soldering iron
2) 24" bar clamps
1/8" & 1/4" drill bits
#2 Phillips screwdriver
100 grit sandpaper
2" paint brush
Nice but not necessary:
Table mounted Router with 3/8" round nose bit & 1/4" & 1/2" round over bits
Floor standing Belt sander/disc sander
Step 2: Making the Frames
First, cut the frame components on a table saw and miter saw. The first picture show's how I laid out for my chair. Change the dimensions as suits you.
Important note: You'll want to use a hardwood that is on the harder end of the spectrum... like oak, walnut, hickory, etc. Birch, poplar, ash, etc. would tend to be too soft to hold up.
I ripped two strips on the table saw @ 1.5", from which I then cut two 41" boards, and two 16 7/8" boards. From the remaining scrap I cut two 2 7/8" blocks with a 30º miter on one end of each, which will get glued to one of the 16 7/8" front seat support board (see pictures two and three below). Then I ripped a 1 1/4" strip from the remaining board on the table saw. From that I cut two 27" pieces on the miter saw. S Then I ripped the remaining board to 2" wide and cut two pieces 13 5/16", and a third 15 3/8" on the miter saw. Disregard the short pieces in the picture marked "SSB".
Okay, all of your boards are now cut...
Next, you're going to glue together your front seat support. Take one 16 7/8" seat support and the two mitered blocks and glue and clamp them together to resemble the front seat support shown in pictures two and three below. This will create a board that is 3" wide at the ends and 1 1/2" wide in the midst, and allows room for the seat to sag when you sit in the chair.
Optional: I used the 3/8" round nose bit to route a trough in the outside edges of the long boards in which the paracord can reside and be protected from abrasion... and I think it has a more appealing "finished" appearance, but this is not required.
Optional: You can round the ends of your long boards on the disc sander for a more finished look.
Next, route the long edges of all of your boards with the 1/4" round over bit. If you want to duplicate the front edge detail that I used on my seat frame (see picture 5 below), you'll need to reserve some of the routing until after the frame is assembled.
Mark and drill your 1/4" holes for your paracord to go through. I spaced the holes on my back at 2 3/8" vertically and 2 1/2" horizontally. For the seat I put the holes closer, as they will be bearing more weight... 1 5/8" in each direction.
Optional: I used a drill press and drilled the holes at a 45º angle so that the paracord would ride as close to flush with the top surface of the frames as possible. The other end of the holes (on the outside edge of the frames) exited in the midst of the routed troughs. Only do this if you are comfortable with it... it's not required. :o)
At this point your front seat support should be set up nicely. Remove the clamps and use the table saw to put a bevel of 10º on the tops of the blocks to duplicate what is depicted in picture #6 below. Put that same 10º bevel on the bottom of the rear 16 7/8" seat support as well, just like in #6 below.
Okay, with the boards cut, the front seat support glued up & beveled, and the edges routed, you're ready to start assembling the frames. The two 41", 15 3/8", and two 16 7/8" boards make up the back of the chair, while the two 27" and two 13 5/16" boards make up the seat frame.
You will want to mark each end of the long boards where your screws will go to fasten the frames together, then drill (1/8" bit) & countersink the holes. Once that's done, lay the frame components on a flat surface and use the 24" clamps to hold them in position while you pre-drill the screw holes. Go ahead and assemble the frames dry for now. Once you have them all together you will glue one corner at a time, removing the screws, gently spreading the joint just enough to smear some glue inside, then reinstalling the screws. You can skip this technique with the seat supports... just remove one support at a time, glue and re-screw. It's quicker and easier to glue the frames together after you've dry-fit everything together.
A little note on my seat support placement: the bottom of the front seat support attaches 1 5/8" from the bottom of the vertical sidebar, and the bottom of the rear seat support attaches 6 1/16" from the bottom of the vertical side support. These are not rigid laws, but guidelines that worked for me.
Once your frames are glued you can go ahead and sand, stain and poly them... then you're ready for the next step (after they've dried, of course. :o)
Step 3: Weaving the Back and Seat
First I screwed (after pre-drilling the oak!) the 1" webbing just above the rear seat support (see pictures #1 & #2 below) and about 6" from the back end of the seat frame. Then I took a pencil soldering iron and melted holes into the webbing on the seat frame to match the hole spacing on the opposite end of the frame... this is only necessary on the seat frame. Make sure to wrap the webbing as shown to increase friction strength, and don't forget to melt the ends of the webbing well to keep it from fraying... and make sure your screws are tight. Make sure your webbing is tight, as on the seat frame this is what you'll fasten your diagonals. The webbing on the chair back functions to keep one's tailbone from contacting the rear seat support by giving a "soft bar" over which the paracord travels before going through holes in the rear seat support. Picture #3 below is a closer detail of these webs, the seat frame being the one on the right.
I started out weaving the vertical runs, then the horizontals with one piece of paracord... then the diagonals with another. Start by calculating how much paracord you're going to need for your seat back... you can separate the horizontals and verticals from the diagonals. The shorter your pieces the less threading you'll have to do. On my seat back it took approximately 35' of cord to do the horizontals plus the verticals, and another 30' to do the horizontals.
I started by threading one end of the paracord through a hole closest to the corner, tying a couple knots to prevent it from pulling though, then weaving in a zig-zagging pattern through the vertical holes, and then the horizontal holes. When you begin weaving perpendicular courses, weave in and out of the existing cords in an alternating pattern, just like on a tennis racket. When you come to the diagonals, get creative, but be consistent in your pattern.
Important note: As you weave, make sure to tension the cord as tightly as practical as you go along. Don't start another direction until you are satisfied that you've gotten it as tight as you want it.
It's not too important how you transition from one direction to another, nor is it critical how you tie things off... use your creativity, sense of aesthetics and common sense.
Step 4: Finishing Touches
Now you can drill four 1/8" holes (two in each vertical sidebar) to secure the shock-cord. The picture below shows the purpose of the elastic shock-cord, which is to hold the seat frame up against the back of the chair when traveling or stowing. I drilled my holes at 10" and 27" from the top of the sidebars, laced the shock-cord through and tied simple figure-eight knots to hole them in place. The seat frame now slides neatly into place.
Placing the screw-on rubber feet: these act as limit stops and you'll want to place them in such a location as to give you something to indicate the maximum limits of adjustment. Simply set your chair up and slide the seat frame forward and aft to determine the best utility range for your comfort. On my chair I placed two rubber feet on top of the seat frame rails centered at 3 3/4" from the rear end of the frame, and on the bottom at 12 1/2" from the rear of the frame. Pictures 1 & 2 below should clarify this point.
And finally, you can add a pillow of your choice. I simply took an appropriate sized piece of foam rubber and wrapped it in cloth and used a single piece of paracord to tie it into place, creating a "valley" for my head to rest in.
Thank you for viewing my instructable! If you like what you see, thanks in advance for voting AND rating... thanks much & Cheers!