However, I'm a hair under 6'2 and I used to play rugby so I am most assuredly not petite or dainty. When I tried to find a nice swing to put up in my awesome porch I couldn't find any that were even remotely acceptable. They were all too small, too uncomfortable, too flimsy, and just generally not right.
So, I did some poking around the internets and found several designs that had elements that I liked. I made a shopping list and one trip to the hardware store later and I had a couple of hundred dollars worth of stain-grade lumber and various bits of chain and other hardware...
Step 1: Getting Started.
Even though I had a general design in place, some details (like the angle between the back and the seat) were still TBD and since I didn't want to waste any of the not-so-cheap wood I bought, I did a lot of measuring and note taking. I wasn't concerned with specific dimensions as much as finding something comfortable so I looked around at various benches and seats. I
In the end the small bench you see in this photo actually contributed the angle for the back to the seat, the width came from another chair I found and the seating depth was based on the length of my own legs (that also determined its final hanging height which was noted by some of my shorter friends and family who feel a bit small on it)
Step 2: The Back Supports
Where each back support attached to the seat, I decided to create half-lap joints at the angle I wanted for the back and the seat. These were then glued and bolted together making for a fairly strong joint.
The pieces that would make up the seat also had dadoes cut into them where the main structural pieces that it would be hung from would slide in.
Step 3: Porch Swing Skeleton
I dado-cut the pieces that ran lengthwise in the seat (those would be what it hung from eventually) and those slid into place nicely with the l-shaped back/seat pieces. I pre-drilled some holes and screwed each of those points together for extra stiffness. Then it was just a question of adding the top and front pieces and screwing everything in place without screwing anything up.
Step 4: Slat Installation
When I was happy with the arrangement, I started attaching them. This part seemed to take forever since I was pre-drilling every hole. I used a convenient spacer to keep all the slats evenly spread out.
This part was very much a lather, rinse, repeat kind of step. Very easy, but very tedious.
Step 5: A Dry Run
The arm rests were simple, but functional. I wasn't 100% thrilled with them, but they work and I haven't come up with a better option. If I ever do though, they're held in place by bolts so they're easily replaceable.
Step 6: Staining
Even though doing it sucked, I was happy with the end result. I also hit it with several coats of spray on varnish which was a lot easier to deal with than the stain.
Step 7: The Finished Product, Installation Notes
The chain arrangement was taken from my research and it seems to work really well for keeping the swing upright while providing maximum support to the seat area. I'm happy with it, although it did make it a fair bit more complicated to hang the swing in the first place.
I also used 4 porch swing supports. Normally they're sold in pairs for use 2 to a swing, but I thought this worked better. They're rated at 250+lbs per support and they're put into the rafters in the porch ceiling so they're not going anywhere.
My estimate is that the swing can probably safely support about 700-800lbs. I've loaded it to 600lbs without any problems and really, it's plenty strong enough to handle 2-3 people of any normal-ish size. At this point it's also been in place and in use for a little over 4 years so I'm pretty confident about its sturdiness.
Oh, I did add some extra supports at the bottom. If you look closely you can see angle braces running along the bottom of the main supports. Strictly speaking they're not absolutely required, but after spending all that time building the thing I decided to err on the side of safety so I added those on before I put it up.