As far as the design, the world is your oyster. Look around and see if there are any designs already there that you can emulate and blend.

Many people get enamored with the golden ratio (1: .618..) and find it everywhere. Simple integral ratios also work well (1:2, 3:2, etc). Use these to determine proportions of height, thickness, and width

You cannot cut an internal hole with a band saw. You can cut it with an entry / exit kerf that you can close back up with glue.

"Hardwood" is a botanical term determined by the way the seeds are formed (angiosperm). It does not indicate density of the wood. So there are no "semi-harwoods." That said, poplar would be a good paint-grade choice. You may need to laminate up some wood to get a a good thickness if you cannot find things other than 4/4 (3/4" thick) wood.

Second the recommendation of using poplar. That wood is often referred to as 'painter's wood' because it paints very well.

One way you can make brackets like you want using the band saw is to make the brackets in three pieces. The top, back and gusset(piece that is the bracing piece) and then glue and screw them together.

Get paper and pencil, lay out the size by making a square. Make the top/back at least 3/4" thick(you can buy poplar that thickness at home improvement stores or lumber yards. You will also have a choice of different widths, or you can rip long pieces to what ever width you choose.

Those two pieces can be cut on the table saw.

Then design the gusset. Those can be cut on the band saw. You can glue two or three together or use a single piece, depending on how chunky or how thin you want the look.

You guys are great. Must admit to not clearly understanding all you said, bobsmyuncle, but I'm suffering from reno fatigue - that's my excuse and I'm sticking to it.

I'll get some poplar Monday. Just knew I didn't want to use pine. Good lumber yards near me.

What I also need to know is how much weight these brackets can support. Have gardening and cookbooks I'll be shelving and my dishes are very heavy. Studs are on 16" centers. Rather than guessing, I'd like to know what spacing I can use. Want as few brackets as possible. Length is OVER 8' by a few inches, so I'll get 10's for the shelves.

Rosie, with gratitude just oozing!

Another trick that can allow the use of thinner brackets is to use wood to cover over a metal brace.

I have even gone so far as to drill & tap threads into the metal portion to allow flat head brass screws to be used to hold the wood covers on the metal.

A relatively small cross section of hardwood at 45 degrees is stiff enough for rather heavy loads with the metal concealed behind the wood.

Wow, those ones on ebay are gorgeous. So call me stupid, but is cost the reason you aren't just buying a few of those?

Having just purchased a whole lotta lumber, I'm here to say they aren't exactly giving the stuff away, even poplar. I'd cost it out and consider your time too before rejecting simply buying those ones, unless they're the wrong size or something else is wrong with them.

Having said that, I've used a lot of shelf brackets and would point out that the strength of the bracket also depends on the method of its attachment to both wall and shelf. From the photo, the ebay listing seems to suggest that there are maybe keyhole openings sunk into the backs of these ones. You need to think about whether that's a good enough method for major weight-bearing. Seems to me you're putting a lot of faith in the head of a screw and the secure installation of the keyhole, if my understanding of the forces involved is correct.

If you decide to use a through-screw method instead, you have to be able to get to it with a drill/press and with a screwdriver. I've done a lot of swearing while trying to drive screws where I can only insert the screwdriver obliquely. For that reason, as well as to accommodate the bandsaw, it might be good to design something that you can assemble as you install it.

I like Brickeyee's idea of using metal to give it real strength. That said, it bugs me when I look at a shelf and it doesn't look strong enough to support the weight on it. That's why I don't like floating shelves; it makes me nervous just to look at them. The design of a bracket has to instill confidence!

To go in a completely different direction, have you looked at the metal brackets available at Lee Valley? They may not convert you from wood, but might give you some ideas. I have the Large Cast Steel Brackets in one installation and I still admire them after years of having them.

KarinL

Here is a link that might be useful: Lee Valley shelf brackets

"Wow, those ones on ebay are gorgeous."

To each their own, but I think they look rather clunky.

"...it bugs me when I look at a shelf and it doesn't look strong enough to support the weight on it. That's why I don't like floating shelves; it makes me nervous just to look at them. The design of a bracket has to instill confidence!"

I actually prefer the light look and am not bothered at all by things that appear light but actually have adequate strength for the job.

I have made torsion box shelves with concealed ledgers (AKA 'floating') that can be used as seats, let alone for holding objects and books.

Well you might not find me sitting on those, but that might be a good thing in your view :-)

Anyway, to the OP, you should maybe try to get ahold of the Jan 2007 issue of Martha Stewart Living magazine. She's got a whole article on brackets, many of them wood including some huge ones in her own kitchen. And she also addresses a way of attaching wood ones.

KarinL