Things You'll Need
Diamond abrasive wheel
There are several reasons you might need to cut a magnet. You may need it for arts and crafts, to replace a broken or lost magnet in a motor or for a science project.
If all you have is a large magnet and you need to cut down its size, there are many ways to do it. The technique you choose should depend on the style and type of magnet that you are trying to cut. A flexible plastic magnet that sticks to a car, for instance, is a rubberized magnet that is easy to cut with shears. Ceramic and magnetite, the most magnetic mineral on Earth, magnets are much harder and much more difficult to cut, requiring a diamond-plated blade.
Put on work gloves. Cutting a magnet, even a rubberized magnet, can result in shards that may cause splinters. Work gloves will also protect you from the metal shears you'll be using.
Mark a line on the magnet wherever you want to make a cut, whether it's one place or several.
Cut the magnet with metal shears, following your line guide.
Ceramic and Magnetite Magnets
Put on a protective nose and mouth mask, heavy duty gloves and protective goggles. In addition to blade danger to the hands, cutting these magnets will send dust and filings into the air that are dangerous to inhale and that can fly into your eyes at a high velocity, causing great harm. Every cutting technique for these magnets requires protection.
Place your magnet in a vise. A vise helps you gain leverage while using a hacksaw. It also prevents your magnet from slipping around beneath your sawing, which is important in retaining its magnetic properties. Excessive vibration can dislodge the tiny magnetic electrons in the magnet, which are normally aligned in north and south directions, diminishing or removed their magnetic properties completely.
Draw a line on your magnet with a marker at the point where you want to cut it.
Use a hacksaw to cut the magnet, following the line guide. If that doesn't work, move on and try another technique.
Place your diamond-plated wheel on your dremel, tighten it in place and turn on the device. While the wheel spins, place it directly on the marker guide you made on the magnet, pushing downward as you go. Make sure not to put an excessive amount of pressure on the dremel or you may bend the wheel. If this doesn't work, you can try one more cutting technique.
Place a chisel along the guide mark on the magnet. Hold it in one hand and use a hammer to strike the handle of the chisel. This may work to break the magnet in two if cutting fails. This should be your last option, as it has the highest possibility of damaging the magnetic properties as earlier described.