How to Use a Dremel or Rotary Tool Correctly!
Few power tools are as versatile as a rotary tool, and for some jobs, a rotary tool is the only practical choice. Just try and name another tool that can drill, cut, grind, sand, file, buff, debur, carve, engrave and polish.
A rotary tool is pretty darn easy to use, too.
There are three keys to success:
- Select the right bit, wheel, brush or other attachment for the task
- Set the correct tool speed
- Apply the right amount of pressure to the workpiece
Let’s start with the basics. I’ve selected a typical Kawasaki Dremel Tool Set that includes a rotary tool and a vast selection of accessories. A kit like this will pretty much answer the needs of every hobbyist and do-it-yourselfer on the planet.
Kawasaki Rotary Tool Set
Let’s look at the rotary tool itself. First make sure the tool is unplugged now and whenever you change bits, clean, maintain or store your rotary tool. One of the keys to the versatility of a rotary tool is the variable speed function. This Kawasaki model has a speed adjustment dial on the back of the tool that allows speed adjustment from about 8,000 RPM to 30,000 RPM. Adjustment is made by rotating the dial, in this case clockwise for higher speed and counterclockwise for lower speed.
Rotating The Speed Dial to Adjust RPM
Now is probably a good time to don some safety glasses, plug in your rotary tool (without any attachments attached), turn it on and play with the speed control. This is a good way to get an idea of how the tool feels when running at slow, medium and fast speeds.
There is a noticeable difference, as the tool motor exerts a bit of centrifugal force as speeds increase.
Now turn off the tool and unplug it – let’s look at the business end of the tool where bits and accessories are attached. Note the silver shaft lock button on the side of the tool.
Rotary Tool Shaft Lock Button
If it weren’t for this button, you’d never be able to load a bit into the tool. To see why, grab the knurled collar at the end of the shaft and try loosening it by turning it counterclockwise. You can turn it all day by hand and nothing useful will happen.
Now push and hold that silver button with your thumb and turn the knurled collar counterclockwise again. The collar will spin freely for part or most of a revolution, then the silver button will depress all the way into the tool body. At this point the knurled collar will stop spinning uselessly, and you can loosen and/or remove it either by hand or with the mini-wrench included in the kit.
Pushing the Shaft Lock Button
Go ahead and spin the knurled collar off the threaded shaft. Underneath that collar is another critical part called a collet. The collet can be pulled straight out of the shaft by hand -go ahead and pull it out and have a look at it.
Rotary Tool Collet Assembly
Note the collet has slits cut into the sides; this allows it to clamp down on the shaft of a bit. Some rotary tool kits like this one have a few different collets included of varying shaft diameter.
Changing a Dremel Bit
Different bits have different shafts diameters to match these collets. Take a look at the drill bits in the set we’re using – note the shaft size difference between the smallest and largest bit.
Rotary Tool Bits with Various Shaft Diameters
I’ll bet you can guess what to do next – yep, you’ve got match the collet size to the bit shaft size. This is a trial and error process, but not a difficult one. Once you’ve selected the correct collet size, load it into the tool then screw the knurled collar back into place lightly.
Load the bit into the collet, then push that silver button to lock the collar and tighten the whole assembly down. Don’t go all he-man when tightening the bit; the design of the collet assembly is such that it will hold a bit firmly without a lot of torque.
Selecting the Right Bit
Now that we know how to load a bit into the tool, the next task is to figure out which bit to use for a particular task.
The Kawasaki rotary tool kit we’re using here has over 190 bits and attachments, which is a testament to this tool’s versatility. Let’s start with the most familiar: drill bits. Why use a rotary tool to drill holes if you have a perfectly good cordless or corded drill?
Rotary Tool Drill Bits
Two good reasons are precision and control. It’s much easier to hold and control a relatively small and lightweight rotary tool versus a heavy full size drill, especially when using a very small diameter drill bit to drill very small holes. If you need to drill the hole in a precise location, again this will be much easier with a small lightweight tool.
When drilling holes, keep the tool speed at a medium setting; too much speed will make it difficult to control the rate of drilling and may distort or melt plastics. It’s also critical to keep the tool and drill bit aligned with each other and square to the workpiece to avoid breaking a bit with sideways pressure.
Some rotary tool kits have unusual looking bits with odd-shaped sparkly tips. These are diamond-coated engraving bits. As the name suggests, these can be used to engrave or cut hard materials like metal, gemstones, ceramic, glass and plastic. The different shapes can be used for everything from drilling to channeling materials.
Diamond Coated Engraving Bits for Rotary Tools
Up next are grinding stones. These come in a myriad of shapes and sizes. Two common stone materials are red aluminum oxide and green silicon carbide. In our Kawasaki rotary tool kit, both the red and green stones are 120 grit, a medium grit useful for general grinding and shaping.
Rotary Tool Grinding Stones
These stones can be used to grind and shape precious metals, gemstones and non-ferrous metals like aluminum and brass. When grinding, it’s best to keep tool speed on the slower side to help control the amount of material you’re removing. Here’s another important tip for grinding stones – never use a grinding stone that is cracked or chipped as it can fly apart at high speed and cause property damage or injury.
Many rotary tool kits also come with a selection of brushes. For example, our Kawasaki Rotary Tool Kit includes nylon, stainless steel and brass brushes.
A nylon brush is handy for buffing, polishing and light duty cleaning. The metal wire brushes are much more aggressive and thus useful for removing tarnish and rust from metal surfaces.
Nylon and Wire Brushes for Rotary Tools
Next up are mandrels and the various accessories that are attached to the rotary tool using a mandrel. The Kawasaki Rotary Tool Kit we are using here includes three types of mandrels:
- One that looks like a shaft with a wood screw on the end – used for attaching “soft” accessories like cloth polishing wheels
- One that has a small screw and washer threaded into one end – used to attach “hard” accessories like polishing stones and cutting wheels
- One that has a rubber drum on it used to attach sandpaper drums