If asked how important casters are to your life you probably wouldn’t even know what they were. A caster is basically a wheel and fastener that attaches to something (typically furniture) to make it mobile. Even if you already knew that, you’d probably still say casters don’t play a large role in your life. The truth is casters, invented by David A. Fisher in 1876, are quite important to our modern lives. They impact us at the office where most desk chairs and some file cabinets are equipped with casters. They’re huge in the medical industry where just about everything needs to be mobile. Casters are also used in the home to make things more convenient. However, just like you wouldn’t put a tractor tire on your car, not all casters are right for all pieces of furniture. Before getting casters, if your furniture is under warranty, it’s best to check with the manufacturer to ensure the warranty will still be honored once casters have been attached. After that, use this handy guide to help you find the right caster for the job. There are several things you need to consider when shopping for casters, including: • How the caster will attach to the piece of furniture • Type and weight of the piece of furniture • Type of movement desired (linear or multidirectional) • Flooring • Special features needed (ex. locking casters) • Looks How it attaches - There are two main types of casters to consider: Post (a.k.a. stem) and screw-on (a.k.a. plate). With a post (a.k.a. stem) caster, a socket or cylinder is inserted into the piece of furniture generally on the leg or at a corner. Then the straight piece of the caster (the stem) is inserted into the socket. With a screw-on (a.k.a. plate) caster, a flat piece of metal holds the caster in place and is screwed to the bottom of the piece of furniture. Type and weight - It’s very important that you know the weight of the piece of furniture you want to attach casters to. Avoid guessing at the weight as doing so could result in damage to the furniture or physical injury. Once you know the weight, start looking at casters. What you’ll need to do, once you find a caster you like, is multiply the capacity of the caster by the number of casters you’ll be attaching to the piece of furniture. The resulting number is your maximum total weight. If the piece of furniture weighs more than that number you’ll nee to choose a different caster. Example: The casters you like have a capacity of 100 pounds. You’ll be attaching 4 to your bookshelf. That means your maximum total weight is 400 pounds (100 x 4). Your bookcase only weighs 250 pounds so these casters are fine to use! You also want to consider whether the weight of the piece of furniture will be evenly distributed on all sides. If not, you’ll want to attach more casters on the heavier side. Other than weight you’ll also want to consider the type of the piece of furniture. Different types should be treated differently. For instance, chairs are a special case. When you’re sitting still in a chair the weight of both you and the chair will be evenly distributed over the casters. However, if you roll then your weight is shifted and is no longer evenly balanced. This is also true when you lean backwards or forwards. In some cases, all of your weight may be transferred to just the front 2 or back 2 casters. When picking casters for a chair, it is much safer to overestimate the weight and pick casters with a higher maximum total weight capacity. Type of movement - Think about how you’ll want the piece of furniture to move. If its a desk chair you’ll probably want it to be able to move a full 360 degrees, but if its a coffee table just moving in a straight line is probably okay. Make sure you get casters that support the type of movement you need. Flooring - The type of flooring you have will effect which casters you can use. If you have wood or smooth floors (ex. laminate or ceramic) that need to be protected from scratches, scraps, marks, wear, and other damage you’ll want to go with soft casters. Typically soft casters are made of polyurethane or rubber. If you have carpet, you’ll want to pick casters that won’t snag on the carpet every time you try to move. Go with hard casters. Keep in mind that the thicker the carpet the larger you’ll want your caster wheels to be. Special features - Consider any special needs you have. There are many, many different types of casters available including those made with locks, shock absorbency, and anti-bacterial materials. Choose the caster that best fits your environment. Locks can be very important if you don’t want a piece of furniture moving around when you try to sit on it. In addition, they can be a must have if you’ve got children and pets. Looks - Will the casters be visible? If your answer to this question is yes, then you need to consider how the caster looks. You may want a colorful caster or one that is a little more decorative so as not to give the piece of furniture an industrial or utilitarian feel. For additional assistance picking the best caster for the job check out our other technical articles or try out our CasterWiz application.