May I recommend a review of this and maybe this to start your quest for the perfect bin.

Lloyd

I have had several compost bins over the years, 12 feet of fence fabric formed into a circle, dry stacked concrete blocks, 4 x 4 corner post with angled dadoes cut in the hold the slats, 2 x 4 end posts with cedar boards in between and T-111 siding made into doors and covers. I'm not sure about a favorite since they all did what they were supposed to as well as the 6 foot wide and high compost piles 45 to 60 feet long.
This article fron Fine Gardening magazine might offer some ideas.

Here is a link that might be useful: Lee Reich's compost bin

I use 2 Biostack bins and I like them a lot. Each is made of 3 bottomless tiers that stack. I don't have to lift the stuff as high to flip. I mix and match the tiers as necessary for a batch that's sitting around finishing and a batch that's cooking.
{{gwi:265829}}

Karen

I've always preferred dry stacked concrete blocks. It's so easy to change the size or conformation as the pile gets larger or smaller. They also hold the moisture in well and never deteriorate. They are especially good for making a compost pile on a concrete slab.

On the third try I found a system that works for me, in Zone 6. Cheap, simple, and easy to use.

My bins are made of 1/4" mesh hardware cloth, four feet in diamater, two feet high. Cost is around $20. My first bin was a plastic square bins that cost $65. Too hard to turn and the bin wasn't big enough. My second system was a tumbler. Too hard to use, made small amounts, and cost $350.

My mesh bins work great. They hold more, can be moved, work well for smelly ingredients, take five minutes to put up (the tumbler took 3 hours), have a low profile, etc.

But there are two other designs that I think might work well for some people:

1) Stackable tier system -- looks interesting, but requires work. I would make mine 4' by 4', which would probably require two people to move the tiers.
2) Garden bench composter -- Garden bench with pile(s) under the bench. This is not for the beginner, as one has to know how to compost without pests and odors. Also, the ones I've seen on-line are expensive ($700-1500), and the dimensions don't seem correct for 'hot' composting. My ideal bench would be back to back seating, and maybe dug a foot in ground to provide a 2.5' pile height.

You've just made me think of a bin style I might try. I like my wire bins because they're so easy to flip. I lift the wire circle off the pile, set it aside, and fork the now uncontained pile easily back into the bin in its new location.

But wire bins flop sideways after a few years, and sometimes the wires pop free and become hazardous---and I gather, from my reading here, that, sometimes, something there is that doesn't love a compost pile (persnickety neighbors), especially floppy piles, so I'd like a wooden bin again---if only they were easier to turn.
I'm wondering about the two side walls either being pinned or hinged to the rear wall. When the bin is full, I'll fold the sides back 180 degrees, replace the (removable) boards for the front of the bin, and start forking the compost up and over the back wall into it the newly formed square. I think I'll make a few of the back wall boards removable, so I don't have to lift the fork too high.
Oh, I'm excited. (I haven't looked at Lloyd's or Kim's links yet (I'm going to); I got too excited about my new plan.)

"But wire bins flop sideways after a few years"
Depends on the wire. I use 1" x 2" weave welded wire, four feet width. It stays put just fine, 8 years running now. Problem is, it costs $3 per linear foot. Yikes! I have used various other less expensive wire with larger weave, and it did do ugly things like bulging outward uncontrollably at the bottom.

Yes, I have one wire bin, still in excellent shape, that I inherited from my stepfather when he died in 1984---I think it might be a 1" x 3" mesh, stiff and rugged stuff Then a neighbor gave me a beautiful roll last year, but I haven't figured out how to cut the tough wire to make bins.

My other bins are all made of junky wire and, while they flop, and take out eyes, I've been using them for at least 8 years, and expect to get a few more years out of them. They're floppy primarily because of a very destructive dog who lives in the neighborhood.

One that turns itself, checks and adjusts it's own moisture levels and temps, and has an "Easy button"! lolol

Yeah right...

I would never switch to round wire bin structure. How do you turn? How do you unload? How do you keep it sturdy?

Mine is: shipping pallets (free from the office) for all sides; a skinny version of the pallet (it is lighter) for the "roof" - it is covered in tarp - helps keep excess rain out. I have four sections - one for leaf mold, three for compost. I usually fill-in two each year and let the third one age over the year. All sections share middle "walls" so I only need 13 pallets for the sides and 3 for the tops, leaf mold does not get cover. All inside surfaces of walls are covered with mesh (small enough to keep content inside). The three permanent sides of each section - slide them over the green fence posts to keep them sturdy. I can turn them with aerator, I can climb up on the pallets, I can remove the fronts to unload compost into wheelbarrow when ready.

Here's where someone might say, 'Don't knock it until you've tried it.' I can lift my wire bin off my pile in less than a minute, set it aside, and start forking the contents back into the bin (in its new location) the next minute. I bet I can turn my pile in less than 15 minutes. When I want to harvest my bin, I lift the wire circle off (in less than a minute) and can start immediately forking the compost into my wheelbarrow. I can work on all sides of the pile, without the dismantling involved in a pallet bin. I don't climb on top of anything, use an aerator, or have to spend time constructing bins. I've had many, many wooden bins---some I built from lumber, and some I built using pallets, and two huge wooden boxes I got from Lockheed years ago, which didn't have an open fourth side and were a pain. The far, far easiest method I have ever used (even easier than an unconfined pile) has been the wire bin set up.

The only disclaimer I might make is that Maine is not a hot climate, so I don't need to worry about my open-sided bin drying out, which you might. I keep my potting soil in a pallet bin now (because I retired it from composting), but I used to line my wire bins with cardboard and keep my recycled potting soil in them as well.

I'm a tumbler kinda guy, as living in the city with stray cats, raccoons and possums will ravage through your pile or your open pit. Tumblers are a bit much, but they're safe from the pests and they keep my tiny yard tight.