Choosing and using a rotary tool
There was a time when I did not own a rotary tool. I had to cut bolts with a hack saw, and I used a Swiss Army knife to trim Lexan bodies. Then one day I bought a Dremel tool, and the Dark Ages officially came to an end. Fifteen years later, my Dremel remains the single most important tool on my workbench. Its versatility never ceases to amaze me, and I am constantly finding new uses for it. This article will guide you through purchasing a rotary tool, selecting bits and performing a few common RC-related tasks.
TOP FIVE BITS
Without the right bits, your rotary tool is little more than a fancy paperweight. Large, inexpensive sets of assorted off-brand bits are available at hardware stores, as well as at bulk retailers such as Costco. Whether or not you buy your bits individually or in a set, here are the top five you absolutely must own:
1: DRILL BIT
You simply cannot function without one of these. Most rotary tools hold an 1/8-inch shaft – pick up an adjustable chuck to use drill bits with different shank sizes.
2: CUTOFF WHEEL
This is your all-purpose cutting accessory. Available in standard (thin, but brittle) and fiber-glass-reinforced (thicker, but much more durable) versions. Get both.
3: SANDING DRUM
Any task that involves smoothing or reshaping needs one of these. Best for soft materials like wood and plastic.
CHOOSE YOUR WEAPON
Rotary tools are available from several manufacturers including Ryobi, Craftsman, Black & Decker and others, but Dremel is the big dog; in fact, many people use the term “Dremel tool” to refer to all rotary tools regardless of brand. Like many power tools, rotary tools come in cordless and corded versions. Cordless tools are convenient and portable, but they typically don’t have as much speed or power as corded versions unless you upgrade to a deluxe model with LiPo or Li-Ion power. If you don’t plan on getting involved in any heavy-duty projects, a NiMH-powered cordless model might be the one for you. Although slightly less convenient because of their electrical tethers, corded rotary tools are more powerful than their battery-powered cousins and can tackle a much wider variety of tasks. Most importantly, a corded tool will never run out of power in the middle of a project – a frustrating experience. If you plan on doing any type of fabrication (this is especially for you rock-crawler guys), a corded rotary tool is a must.
Rotary tools are available à la carte or in various kit forms that include bits, a case, accessories and other attachments. Kits are a good choice for first-time buyers, but don’t spend extra money on stuff you won’t use. Figure out which types of bits you’ll need (or don’t need), and then select your kit. It is worth noting that rotary tools also work great for projects around the house, which might help justify the purchase to one’s significant other. (Warning: this strategy often results in a longer “honey-do” list.)
4: GRINDING STONE
When it comes to grinding metal, this is what you need. You can also use a shaping stone to create your own custom bit shapes.
These are available with various types of wire or plastic bristles in different shapes for a multitude of jobs. For RC, wire brushes are often used to remove rust and to scuff cells before soldering.
THE EYES HAVE IT
If you’ve heard it once, you’ve heard it a thousand times: wear eye protection. Seriously. Rotary tools operate at extremely high speeds, and they are capable of ejecting debris at high velocity. If you enjoy having eyeballs, then it shouldn’t matter how stupid you look wearing safety glasses. Make sure you cover your eyes with something, even if you have to tape some scrap Lexan to your face.
– CUTTING A BOLT
A cutoff wheel is our weapon of choice. Clamp the bolt in a pair of vise grips, using a small piece of scrap cardboard to prevent marring the threads. Turn up the speed to around 25,000rpm, make sure the wheel is perpendicular to the bolt, and apply light, even pressure. Continue steadily until you’ve made it all the way through the bolt, being careful not to put sideways or twisting pressure on the cutoff wheel. Caution: both the bolt and the cut end will be extremely hot, so do not cut bolts over carpet or while wearing open-toed shoes. Ask me how I know.
– TRIMMING A LEXAN BODY
After rough-cutting your Lexan body, chuck a fine-grit sanding drum into your rotary tool. Put on those safety glasses and a dust mask, and adjust your rotary tool for a low to medium speed – about 10,000rpm or so. Using a light touch, carefully grind away the excess Lexan with smooth, even strokes. Keep the tool moving, and work your way around the body. See, I told you it was fun. To finish things off, use a felt wheel at about 5,000rpm to buff the edges smooth.
– POLISHING HINGEPINS
There are a couple of ways to tackle this one. First, if you have an adjustable chuck or a set of collets that fits your hingepins, simply chuck your pins directly into the rotary tool. Adjust the speed to a low setting, apply a little metal polish to a rag, and carefully polish each pin. Be careful not to get the rag caught in the chuck. If you aren’t able to chuck your pins, just use a felt wheel in your rotary tool at 10,000rpm max to polish the pins.
– REMOVING A SCREW WITH A STRIPPED HEAD
Load up a cutoff wheel and set the speed to 25,000rpm. Fiberglass-reinforced wheels
are fine for larger screw heads, but you’ll want to use the thinner standard wheels for everything else. Slowly cut a slot into the head of your pesky screw, being careful not to cut into whatever the screw happens to be threaded into. With the head now slotted, you can use a standard flat-blade screwdriver to remove the screw. Countersunk screws can be tricky, so take your time with these. A cutoff wheel that has been worn down to a very small diameter does an excellent job of slotting countersunk screw heads without damaging the surrounding surface.
The more you use your Dremel tool, the more uses you will find for it. Respect your rotary tool and be safe, but don’t be afraid to experiment. The next time you’re at the hardware store or hobby shop, pick up a few bits that look interesting. Play around with some scrap material, old parts, or whatever else you have lying around, and see what the different bits will do. Once you’ve used a rotary tool, you’ll wonder how you ever got anything done without one.
Dremel – dremel.com