Vol. 64, No. 3 Autumn 2019 248 Rotary carving tool


T e main tool that you will be needing to produce a good carving is a good quality rotary carving tool. (Figure 1) T is is an NS K Electer GX. T ere are several good rotary tools on the market that are akin to this one in performance and features, and you should look at the choices available to you before deciding which one to buy. Most jewelry supply companies will carry these carvers. Look for a 12-volt DC rotary carving tool. Such tools will vary in features off ered. I recommend that you look for the following features before making this major purchase:


A. Choose a 12-volt DC motor and power pack, (transformer with controls). Direct current provides lots of power even at low speeds.


B. Variable speed: 0 to 20,000 rpm is fi ne. Some go to 30,000 and higher, but it will not be necessary. T e 0 rpm is important when using a diamond burr to sand your carvings. If you want to sand very fi ne lines, like sometimes found on a taff rail, a very slow rpm will smooth it, faster speeds will sand and alter the shape. I use a diamond ball bit at about 60 rpm or below to smooth my surfaces. Sometimes I fi nd that just the diamond ball alone, without its turning, is a great sanding device.


C. T e handset must be light and small, fi tting the operator’s hand in a comfortable fashion like holding a pen. You might fi nd yourself holding this tool for eight to twelve hours per day; a heavy handset will cause cramps and fatigue.


D. A quick-change bit release is a must. T e tool I use has two collets, one is 3/32-inch and the other is 1/8-inch. T is will fi t the bits you will be using in this carving tool. If you need a larger shank, like 1/4-inch, use tools that are made for that size shank. It is an extremely rare occasion when I need a larger shank. My handset changes bits quickly by means of a small lever: snap and it is open, snap and it is closed. You will be changing bits frequently, so do not be caught having to locate the tool needed to do the job every time you want to


change a bit.


E. Reversibility: You might fi nd this unnecessary, but I fi nd it useful using a burr in reverse when I want to polish an area or remove wood very slowly. It also helps to make a custom tip that works in reverse when dealing with a brittle grain direction. Be sure to go slowly when in reverse; it can burn wood beautifully. Also, reverse might be used to sharpen a burr slightly.


I have never used foot pedal rpm control in production. I tried it but found it unnecessary. When you install a new cutting burr into your hand piece, it is there to do a particular job, and you will be using it at a comfortable rpm continuously. Generally, the larger the burr, the slower the rpm, the smaller the burr, the greater the rpm. Tiny tips the size of a pin point might require speeds exceeding 20,000 rpm. But, then again, the rpm is determined by the diameter of the burr and the aggressiveness you desire.


T e cutting bit


T e most common device used in your rotary tool for cutting is the dental burr. T is is a cutting head mounted on a shank, generally 3/32-inch in diameter, and is designed for cutting hard compositions like


2. A round diamond burr for customization work.


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