Self-supporting shelves, unlike the wall-mounted type, can be moved wherever and whenever you like – without leaving screw holes to be plugged.
A part from their most obvious advantages over built-in units, freestanding units don’t have to be tailored to fit any irregularities of walls and alcoves. But, because they aren’t fixed in position, you have to devote a bit more time and thought to making them rigid. This is often a matter of making a straightforward box, although frame construction is another possibility. Either way, it is important to remember that the shelves themselves won’t add much stability, particularly if they’re adjustable. You need additional stiffening to compensate the tendency for the whole unit to fold up sideways into a diamond shape.
The basic box
Always keep your materials in mind. MDF is best. The options are, of course, solid timber or manmade boards. Plywood is probably the best all-rounder, but it’s quite expensive. Chipboard is cheap, and chipboard screws make a strong butt joint. In solid timber and blockboard, you’re restricted by the fact that you shouldn’t screw or nail into end grain. Dowels or plastic jointing blocks are good for assembling most of the structure, but dowels are less than ideal for corners, because a dowel joint isn’t all that rigid. A timber strip glued and screwed into both surfaces, can add some necessary reinforcement; but shelf units often rise above eye level, and you’ll have to be careful that it’s not unsightly as well. A barefaced housing joint is one remaining possibility – that is, apart from those afforded by power tools. A circular saw or router makes it a lot easier, for example, to cut rebate joints or mitres. An additional point is that plastic facings such as melamine laminate won’t accept glue, so that some form pf screw fastening is virtually your only way of fixing other components to them.
Stiffening the unit
The simplest way of making a unit rigid is to pin a back panel to the rear edges of the box and perhaps even to the back edges of the shelves as well. However, there may be occasions (for example, if the unit is to stand in the middle of a room) when you want a more open, airy look than is possible with this unmodified form of construction. In such cases the answer is to add bracing to the actual box components themselves. Even if you are incorporating a back, the extra stability such bracing provides won’t come amiss – especially on large units. The principle works as follows. Flat boards bend under stress. You can counter this by fixing lengths of reinforcing timber along them, preferably on edge. Every board thus dealt with helps to keep the whole structure stable. You can even stiffen the open (front) face of the cabinet, by running bracing members across it, provided these are firmly jointed to the cabinet sides – say with dowels, plastic jointing blocks or steel angle repair brackets. A recessed plinth does this job and the type of plinth that’s made up separately stabilises the cabinet by stiffening its bottom. Frequently the neatest way of stiffening the front is to place such reinforcement along the shelves – either underneath them (inset if you like) or fixed to their front edges. Rectangular-sectioned timber such as 50x25mm (2×1 in), or a metal L-section, is ideal here. The procedure has the added advantage of strengthening the shelves, and you can treat intermediate shelves in the same way – not just the top and bottom panels.
Supporting the shelves
You can fix shelves into the unit by any of the methods appropriate for box construction using hand tools. The strongest and most professional of these is to house the shelves into the uprights A stopped housing makes the neater joint here, since it means the front edge of each upright is unbroken by the ends of the shelves, but a through housing is quite adequate. The other invisible fastening for fixed shelves is dowels. Screws will leave plastic caps showing on the outsides of the side panels. The choice between these methods depends largely on your materials. A plastic-faced upright panel means the dowel joints can’t be glued, so you rely even more than usual on the main box for strength.
Timber shelves, on the other hand, can’t be screwed in directly because you’d be going into the end grain. Plastic jointing blocks are an obvious and fairly unobtrusive possibility. Timber battens, glued and pinned, or screwed and if possible glued, to shelves and uprights are tough; they can also be quite neat if you chamfer their front ends, cut them off at an angle, or hide them with a front rail. A triangularsectioned timber ‘stair rod’ moulding, or an L-sectioned strip of steel or aluminium, is neater still.
You can create artificial housings by using pieces of timber or board, the same width as the uprights, pinned and glued to their inside faces, and leaving just enough space for the shelves to fit between them. This means you can make the uprights themselves a bit thinner. A rather different approach is to let the shelf ends rest on small supports sticking out of the uprights. These might be screw eyes (with screws driven up through them into the undersides of the shelves to fix them in place if necessary); they could be 6mm (1/4in) diameter dowels. You can also get several sorts of plastic studs which screw in, nail in or push into drilled holes. Some are specially designed for glass shelves.
And sometimes the hole is filled by a bush which will accept a number of different types of stud. Lastly, there’s a very neat way to make the shelves in a freestanding unit fully adjustable. This is to use ‘bookshelf strip’ – metal strips with continuous rows of slots, into which you clip small metal lugs; the shelves rest on these. The strips (of which you’ll need two each side) can be simply screwed to the insides of the uprights, or fitted into vertical grooves if you’ve got the power tools to cut them. A home-made version of this system uses removable dowels in regular vertical rows of drilled holes.
Installing dividers
For the distances you can safely span with various thicknesses of various materials. Really wide shelves may need extra support in the middle. Vertical dividers will provide this, and can also add to looks and usefulness. They’re usually housed or dowelled in at top and bottom, and halved over intermediate shelves. Alternatively, a square- or rectangularsectioned timber upright, fixed to the front edges of the shelves, will help matters. It can be glued and pinned to the shelves, dowelled in or notched over them.