Tattoo Mechanics: Exploring the Classic Two-Coil Machine
- Livia Michael
- 2 hours ago
- 4 min read
Greetings, internet! It's Livia Michael again. Here at Speakeasy Tattoo in Los Angeles, I am learning the intricate mechanics of tattoo machines. There are a variety of tattoo machines on the market. However, there are two main types of machines that tattooists frequently use: coil and rotary.
Coil machines are what most individuals imagine when they hear the word, ‘tattoo’ (e.g. the heavy metal machinery and the loud buzzing sound). This design was originally patented by Charlie Wagner in 1904, which was based on another patent by Thomas Edison, for an electric stencil pen. Wagner’s coil machine patent was foundational for the tattoo industry, and the technology for coil machines has not changed significantly since then.
The overall mechanics of a two-coil tattoo machine are as follows: An electromagnetic current starts and stops in a continuous loop of electricity which causes the tattoo needle to move up and down into the skin. This loop repeats itself anywhere from 4,000 to 10,000 times per minute. A two-coil tattoo machine generally consists of a frame, grip, needle, tube, coils, capacitor, front and back springs, armature bar, clip cord, and contact screw. A needle is installed perpendicular to a spring-loaded armature bar. In its initial position, the armature bar is touching the contact screw, which creates a loop of electricity that is connected to the coils. The coils in the machine contain an iron core wrapped with metal wire. When a power supply is sent through the machine by way of a clip cord, the coils become magnetic (A capacitor is used between the coils to help the power flow through in a stable manner). This magnetic power causes a downward pull on the armature bar, which therefore sends the needle down. When the armature bar goes down, it is no longer touching the contact screw, which breaks the circuit, and sends the bar back up to its initial position. This process repeats itself in a cyclical nature, as long as there is a power source that is connected to the machine.
In terms of adjusting the speed of the needle penetrating the skin, one does not need to add more power or voltage. A tattooist must adjust the height of the contact screw in order to make the motion of the armature bar go faster or slower. For example, the contact screw must be higher to slow the speed of the armature bar, and lower to increase the speed of the armature bar. This is considered the ‘throw’ or the ‘stroke’ of a tattoo machine, meaning the distance the armature bar travels from the initial position to the downward position. On the other hand, the force of the hit of the needle can be adjusted by increasing or decreasing the voltage in the power supply. As the voltage increases, the magnetized coils become more powerful, and therefore send the armature bar down with more force, making the needle hit with more impact on the skin.
Coil machines are unique from other tattoo machines in that they utilize electromagnetic force to operate. However, there are also different variations of coils, which can affect the operation of the tattoo machine. Coil height is one of the factors that can play into this. A coil with a shorter metal core is going to cause the needle to penetrate the skin much faster, as it absorbs more of the electromagnetic current. However, the needle hit does not contain as much force because there is a greater amount of resistance being generated. On the other hand, a coil with a metal core that is taller is going to move much slower, as the electromagnetic current has a larger space for power to be distributed. But, these taller cores allow for a much more forceful impact by the needle into the skin.
In addition to coil core height, the amount of times the core is wrapped with metal wire affects the speed and power of the needle hit as well (however, this effect is independent of the coil core height). If a coil has more wire wraps around its core, this creates more resistance for the electromagnetic currents, which will cause the machine to run slower, but with more strength in each hit. Conversely, if the coil has fewer wire wraps around its core, the machine will run faster, but with less strength each time it pierces the skin. The voltage required for powering a coil machine also depends on the number of wire wraps, as there is more resistance in coils with more wire wraps. For example, a 12 wrap coil machine is going to require more voltage to run smoothly than an 8 wrap coil machine. A tattooist must experiment with these different factors in order to discover their working preferences as well as other artistic techniques in their tattooing.
Coil machines are at the heart of modern-day tattooing. The technology may be over one hundred years old, but many artists prefer to learn and work with the inner-machinations of these devices in order to feel a stronger connection to their work. These heavy, steampunk-esque machines can make a tattoo artist’s hand more grounded and intentional, which can only aid in the creation of permanent art on another person’s body.
Until next week...
-Livia Michael
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