Hmm, have you decided on going with 8-frame or 10-frame equipment? ...mixture of deeps and mediums??? Just thought I'd open that can of worms up for you.
NasalSponge mentioned the specs for beespace. There is really no "close enough" in regards to it. You are within in the range of beespace or you are out of the range...if you are out of the range then the bees will adjust things "accordingly". Beespace was Langstroth's discovery that revolutionized beekeeping and has been used since the mid-1850's. It has been a constant in Langstroth hive systems ever since...and is about what Langstroth is remembered mostly. Beespace is found in natural hives (trees, walls, any comb structure) and is used in artificial hive systems besides in Langstroths. Leaving a frame crooked in a super creating a space larger than beespace and the next time you check the hive you will see how efficiently the bees fill that space with bridge comb, double comb, etc.,. You can see the example of too small of a space each time you start prying up frames that are glued down (nothing really a lot you can do about the frames, though, but it makes a good example for too small of a space
). I've found that *sometimes* you can get by with gambling on beespace but most of the time the ladies will call your hand on it.
You could buy the equipment for a hive and copy that but be aware that even commercially cut equipment may have a bit of error in it's dimensions...I've noted that in my first two years of beekeeping. Since you appear to be a skilled woodworker I would get the precise, standard dimensions of Langstroth hive equipment and go with that...paying careful attention to beespace. Each box and it's frames work in conjunction with the box and frames below or above it to insure that beespace is respected.
Building boxes...the Achilles heel is at the corner joints where end grain is exposed. Water will soak into this quickly. Rabbet, box, and butt joints are the three most regularly used joints. Some people use screws, some people use nails, some people use staples. Rabbet joints leave the least end grain exposed. All three joints are widely used, though, with folks swearing by each one. The trick is to do a very good job of sealing the grain. I paint my rabbet jointed cypress boxes with exterior latex. When putting them together I will apply a very liberal amount of TITEBOND III (there are 3 versions of Titebond) to the joint before nailing them together. The excess glue that squeezes out of the joint is "painted" onto the end grain of the wood with my finger...this really helps sealing the wood. I later paint the boxes with the exterior latex. You probably wouldn't want to do this with a clear finish, though, as the glue would show. Where are you going to put your hives?....will they be a showpiece for you garden or will they be outback and out of sight? I like utilitarian over looks...but that is me and my hives are out back a bit, too.
When you paint or stain your boxes position them upside down so that all that exposed grain of the handholds will be turned up and you can get lots of paint/stain into them.
Frames...if you decided to go with plastic frames then naturally you would buy them...I don't use them down here in the south because I think there is many places for small hive beetles to hide in them. Beetles aren't as bet up where you're at. If you go with wooden frames *I* would buy them, too...tedious work it looks like to build them from scratch. You can buy medium frames for down around 75-cents each in 100-lots (maybe less?). I use wedge top bar frames...I can put foundation in them or turn the wedge sideways and glue/nail it in for foundationless frames.
Foundation...I use mostly unwired small cell Kelleys foundation. I started out with unwired foundation because I figured I might want to cut queen cells out for nucs or something and it's easier to cut out of unwired foundation...at least that's the only reason I can think of right now...it was probably just a newbee move. I've also tried a little foundationless but I haven't jumped all the way into that, yet. My mentor uses regular cell wired with no-ears (with wedge top frames). The reason he gives for using the "no-ears" is that sometimes the ears are bent exactly at the right angle and will cause the foundation to bow out on one side at the top of the frame rather than hanging down straight. We both wire our frames horizontally to support the comb...two wires in a medium frame. With wax foundation an electric embedder works good...I use an old trickle charger for batteries...attach each lead to the end of the frame wire, the frame wire heats up melting the wax and embedding the wire into it...a little practice and you're good to go. There are also embedding wheels that are used for "cold" embedding...I haven't had any experience with those.
Oh well, that was just some newbee thoughts...maybe something in there helped.
Best wishes!!!!!
Ed