Adding caster wheels is a great way to make heavy furniture easier to clean behind or to rearrange. With a couple of quick steps, you can roll your furniture around the room as needed. Here's how!
Note: If your floors are uneven or you worry about your furniture staying steady, purchase caster wheels with a locking mechanism so your furniture only moves when you want it to.
Types of Casters-
A post caster wheel is received into the bottom of the furniture leg or corner. Usually, these are the more decorative of the two kinds of casters, with either a metallic ball or a covered cylindrical rolling element. At home stores, these are sold mostly as replacement parts, without the receiving cylinders, but you can find sets of casters and cylinders online. You can't just drill a hole to receive the post since the receiving cylinder has a "catch" to hold the caster in place, so you do need the cylinder pieces. These casters allow the furniture to be rolled in any direction.
A flat plate holding the caster mechanism is screwed onto the furniture bottom with this kind. These are usually less decorative and more utilitarian, using plain rubber wheels inside of a metal housing. Some are fixed, some swivel, some can be locked in place. The swiveling kind is the most versatile since it allows for moving the furniture in any direction.
Turn your furniture upside down to see what is available as a surface for your caster, which partly determines the kind you'll use. Some items that sit flat on the floor will require screw-on casters. Other items, like some bookcases or desks, will have legs or some other decorative element that sets the actual bottom-up from the floor. These may, with a little work, support either post or screw-on casters.
Build Up the Corners
Since so much furniture is assemble-it-yourself these days, there will often be no extra support at the corners as there is in craftsman-made furniture. Therefore, you'll have to build up the corners before attaching wheels (for long, heavy items like entertainment centers, it's good to also put casters at the front and back center). You can do this by adding pieces of scrap wood to each corner with screws or glue. A very sturdy glue, like construction adhesive, eliminates worries about screw length.
Measure the depth of the leg or toe-kick to decide how much of the caster you want to protrude beyond it. Make sure to account for the pile of your carpet so the furniture's rolling isn't halted by the bottom edge getting caught on the carpet. If you like the looks of your decorative caster or if you don't mind an industrial vibe with the screw-on type, let more of them show. Each type comes in both "showy" and less obtrusive variations.
Cut pieces of scrap wood, with surfaces big enough to hold your chosen caster and thick enough to allow your caster wheel to protrude the right distance (stack various thicknesses until it's right), and attach them into the corners of the furniture. Remember that if you're using a post caster, this built-up area needs to be deep enough for the receiving cylinder, and if you're using the screw-on type, there needs to be enough extra wood surrounding the flange so the screws won't split out the sides. Additionally, if your furniture bottom is flat, make sure the flange of the screw-on caster is far enough from the edges that the screws don't split out the sides.
Add the Casters
Drill the post holes and secure the receiving cylinders inside them according to the manufacturer's instructions. Then, insert each post caster into the cylinder until it "locks."
For screw-on types, pre-drill screw holes for the caster flanges and attach each flange firmly. Then, turn the furniture right side up (being careful not to lean all its weight on the new casters while turning it) and you're ready to roll!
Remember when moving heavy furniture around you should keep your hands at about the midpoint to avoid overbalancing.