Tattoo machines started out using a very simple electric alternating current. The original tattoo machines were very simple, and in the last hundred years has really changed little in regards to coil machines. Tattoo machines come in a selection of styles and most artists have their own preference, within that there are also fads of whatever is the new “in” thing to use or whatever the rockstars are being paid to promote. Generally tattoo machines fit into three categories – coil, rotary, or pneumatic.
The pneumatic or “pneuma” tattoo machines are a great example of a fad. When they came out they were extremely expensive and considered revolutionary because they could be autoclave sterilized. These tattoo machines used compressed air to force a motor to spin which in turn would crank the needle bar up and down. They were very light and quite easy to use and most of the big name artists were photographed using them. That being said fast forward a few years and you will find few artists are still fans. The compressors are just as expensive if you want something that isn't as loud as a freight train, if you plan on autoclaving machines after every tattoo you need to have many, and the simple cost alone make these tattoo machines outside the realms of the average tattooers needs.
Coil tattoo machines are the recognizable equipment that most tattooers still use. They tend to be reliable and are often highly adjustable so they can be made to fit the artists “hand” and work for the artist rather than the artist adapting to the machine. With this in mind simple adjustments can make coil tattoo machines give a variety of effects; from slow running black and grey to hard packing liners, all use the same basic mechanics with the adjustment of a few screws and angles. A coil machine runs on the concept of alternating current; current comes into the machine via the clipcord and is transferred along wires to the contact point this then attracts a spring attached to the armature bar in a downward motion towards an iron cored coil completing the circuit. At this point the current switches and the process begins again. As the armature bar goes up and down so too is the needle bar forced up and down in the same motion.
Rotary machines have become quite popular at the moment, though it remains to be seen if they will go the way of the pneuma. These are not new machines, the technology has simply been refined. Many rotary machines are ceramic and wipe down friendly meaning there is no need to autoclave and they therefore potentially are not as unsanitary as a coil machine. The Cheyenne rotary system also has a needle system that retracts making it much safer for artists not to risk potential exposure from contaminated sharps. These machines run quieter and more efficient than other types and use the same motor principal as the pneumas only with an electric current rather than air.