Traditional tattoo machines are driven by an electromagnetic coil, similar to the ones used in old electric doorbells. In fact, when the single coil machine was patented by Thomas Riley in 1891, he had built his first prototype using a doorbell assembly. The devices have gotten more and more sophisticated over time, but the technology behind it is still the same: a magnetic circuit moves the needle-bearing armature up and down. Coil machines are relatively inexpensive to produce and remain the most popular form of tattoo machine on the market.
Rotary tattoo machines, with a piston or cam driven by an electric motor instead of magnetic coils, did not come on the scene until almost one hundred years later. Their ability to address some of the shortcomings of coil tattoo machines, however, has led to their ever-increasing popularity.
- Precision – coil machines have a spring that absorbs shock as the artist works. This softer hit can be great for shading, but it also results in vibration as the at tattoo machine itself is hit by force that would otherwise be absorbed by the skin. Rotary tattoo machines, on the other hand, have a simple mechanical design and do not buzz and vibrate the way that coil machines do.
- Power – rotary tattoo machines are generally more hard-hitting than their coil cousins. Even artists that prefer coil devices will often turn to a rotary device when it comes time to shade.
- Versatility – coil tattoo machines are engineered to be excellent liners or shaders, but the same machine is rarely adequate for both jobs. With a rotary machine, the same device can tackle both tasks with a quick change of a cam and needle.
- Comfort – besides having less buzz and vibration than a coil machine, rotary machines are more lightweight. Without the bulk and heft typically associated with coil machines, the artist can work without straining his joints and compensating for his machine’s clumsiness.
Despite its growing use, the rotary tattoo machine still falls behind the coil machine in popularity. Some artists that have learned their trade with coil devices simply do not want to make the change, either preferring the softer hit for shading or not wanting to re-adjust to a new weight and feel. With new artists picking up rotaries as their first tattoo machines, and new models like the Dragonfly catching the eye of experienced artists, however, the gap is quickly closing.