Thread: Joining Shelves - 4 columns x 4 rows

Mate....you are new to woodworking so my suggestion would be to screw the whole lot together with glue. If you use dowels you will have to ALL the holes drilled perfectly to be able to get it together. The overall size of the job is OK to rely on the screws and glue. I would put the internal shelves right across the the otherside and then fit the up right in the centre in as short spacers. To join the spacers on to the shelf I would use a couple of dowels there with a slightly larger hole to accept the dowel. Why larger hole....to give you "wiggle room to line up.
I would use 50mm X 8# long thread screws. In the ends drill a loose clearance hole and countersink then into edge of MDF drill holes that are the correct diameter to accept the threads of the screws.You would only need 2 screws at each intersection. To cover the exposed screws in the ends, you can use a cover cap or even a timber plug of the same colour as your "Alpine MDF". In regards to the back I would use 3mm and nail it on with glue and Softsheet (they have a flat head that works well with 3mm) nails about 25-30 long and spaced about 100mm apart
If you want more work to do you could make trenches in the ends to house the shelves. Not knowing whether or not you have a router.

Personally would avoid dowels like the plague, apart from having to match all the holes, the dowels occupy roughly half the thickness of the board and don't leave a lot of material left to transfer the load.

Option 1 full size top, bottom, sides and inner one piece vertical sections screwed togther to make a frame with two vertical dividers. Drill all uprights for shelf pins, and fit two levels of 3 shelves supported by shelf pins. Back can be scewed inside frame to prevent racking. Use some form of jig to get the shelf pin spacing spot on, you can make one to suit from scrap.

Option 2 a possible cabinet makers option. A frame and back similar to option 1, with the middle shelves continuous instead of the middle uprights. Use cam style knock down fittings to connect the 3 levels of 2 centre uprights. Have attached a pdf of a page from Lincoln Sentries cat showing one option, the Fast Fit camlock. There are other options on preceeding pages of the cat, and others from other suppliers. Some Bunnings stores stock something similar in the Knock down fittings section.

Drill small holes for pin in shelves, large hole for body in uprights (stagger holes for top and bottoms of uprights and shelves to avoid having pins clash), body fits into uprights, leaving pin protruding from ends of uprights. Engage pins in holes in shelves and rotate screw head in body. This draws a metal bar in the pin toward the body expanding the plastic lining of the pin to jamb the pin in the shelf, and the body jambs in the upright recess. Uprights support the weight of the shelves and contents, connectors control sid loadings on uprights. Best way to do these without a CNC router would be to use a plunge router with template guide and appropriate bits and a set of home made templates. Might be a bit high tech if you have very limited tools available.

I made a wall of shelves like this in our old house. I ended up deciding to do it in 6 sections, using MDF. Each section was roughly equivalent to the one set of shelves you're making. I made the uprights as one piece, and routed a rebate for each horizontal shelf to fit into. I made each horizontal shelf one continuous piece, then half-lapped the front of the shelves and the back of the uprights, so that they slotted together like a 3D puzzle. I also routed a rebate in the top and bottom shelf for the middle uprights to slot into. Then I glued and screwed the lot, being careful to make the total box square. That might all be overkill for your situation - it was perfect for what we needed, and stronger than the wall that the shelves were connected to. Pretty easy to do too, since all I needed was to cut each piece to the right length then set up the router for only two different types of cut (rebates and half-laps). I think I only routed in the wrong place once...

Do you want the middle shelves to be adjustable, or are they fixed?

I am looking at something very similar to this right now. It is screwed to my office wall. It has three partitions with two or three moveable shelves in each. I drilled holes using a router and a jig to accept the shelf pins. There are various ways to skin that cat. You can buy melamine chipboard with the shelf holes already drilled.

If you wanted to use dowels for the inner connections, it's easy enough. All you do is locate one shelf where you want it in relation to the divider, drill right through the divider and into the shelf where you want the dowels. Then you take that shelf away, locate the opposite shelf and use the holes you just drilled through the divider to locate the holes in the second shelf. Then you can run a dowel right through the divider and into each shelf on either side. That assumes you want them all horizontally aligned as in your drawing. Use screws and caps to fix them at the sides.