How Tattoo Machines Work
Here's a quick video of the magic behind the machines and below is a more in depth breakdown.
Essentially there are only a few basic types of tattoo machine. The image below shows the classic magnetic coil machine, which uses an alternating electric current to turn magnets on and off in rapid succession to pull a spring-loaded armature bar in an up and down motion. The second is a rotary motor which uses electrical current to drive a spinning motor which is attached to a piston armature that translates the spinning motion into an up and down motion. The third more modern, and quite rare (due to its high cost, loud shriek, and utter inconvenience) is a pneumatic tattoo machine that uses compressed air to drive a piston in an up and down motion.
The electric coil machine is sort of the “Harley Davidson” of the tattoo world. Its loud, rattles itself apart with prolonged use, but has a cultural identification that will never go out of style. Many artists are loyal to this antique, beautiful, elegant, and classic tattoo machine despite its loud buzzing sound, and tendency to need constant maintenance.
The rotary machine is more like the “BMW” of the tattoo world They started out in prisons and at home being made from cassette player motors, and were not very adjustable or responsive to the skin, consequently they were discredited by industry professionals. However in recent years they have made a major come-back as different devices are being developed which allow it to produce an action more similar to the coil machines. They also run almost silent, and are much more maintenance free than coil machines.
Pneumatic machines were developed recently, they require very expensive quiet running compressors, and the running of air lines and filters throughout the shop. They produce beautiful tattoos, as well as a dental drill-like shriek, and a jet of ice cold air exhaust that blows on the client.
TUBES & NEEDLES
The tattoo needles are set at the end of what is called an armature bar, which connects to the part of the machine that travels up and down. The armature bar passes through the “tube” that has a hand grip attached, which is fitted into a vise on the machine to hold it in place. Some artists use tubes that are made of stainless steel, which must be cleaned and sterilized after each use. The steel tubes are preferable for several reasons, however many artists are switching over to disposable plastic tubes like those shown here for reasons of safety and convenience.
The tube is set so that the needles only extend beyond the tip of the tube an appropriate distance, the photo below shows about how far into the skin tattoo needles penetrate. The up and down motion of the needles in the tube create conditions which draw tattoo pigment up into the tube, and allow it to be released when the needles are running in the skin.
The assembled machine is connected to a power supply by a special wiring harness called a “clip cord” or “RCA cord”. The power supply has settings which can control the speed of the machines, etc, and is most commonly activated by a foot switch, to keep the tattooers hands free.
When the artist is working, they will stretch your skin, press the foot pedal, the machine will run the needles up and down as the tattooer passes the tip of the tube over your skin, the needles carry pigment along as they travel and deposit into your skin where it will stay forever.
Essentially there are only two different sizes when it comes to tattoo needles. What are known as #12 diameter, and what are known as “bug-pins”, which are smaller in diameter than the #12’s. There are some variations available within each size, for instance the taper at the end of the needle may be long, or short, and the needle may be smooth or textured. Other than this all needles are more or less the same.
Think of tattoo needles like individual hairs in a paint brush. All of the hairs in a paint brush are more or less the same, but we all know that paint brushes come in all shapes and sizes. The same is true for tattoo needles.
Basically there are have “liners” and “shaders”. Liner needles are grouped together in various quantities in a round configuration, and are often tightened at the taper so that the points are very close together. Shader needles can also be configured in round patterns, as well as fanned out into what we call Magnums or “Mags”. There are other minor variations and some less common configurations that some tattooers use, but essentially this covers what is commonly used.
The individual needles are grouped together and soldered in place to form what is referred to as the “tattoo needle”, the needle is then soldered onto what is called a “needle bar”, which is just a length of stainless steel wire with a loop on the end which can be fitted to the part of the tattoo machine that creates the up and down motion. The unit as a whole is then cleaned, sterilized, and ready to use.
The needle bar is placed within the “tube”, a stainless steel (re-useable) or rubber and plastic (disposable) device which provides a hand grip for the machine, that allows the mechanism to function within and through it, and also to provide a reservoir for the pigment. The amount that the needles actually penetrate the skin is about the thickness of a nickel.
Any given tattoo artist may work with a range of different needle groupings in order to create their own style of tattooing, it is truly a tiny stainless steel paint brush, and what sort an artist chooses is a matter of preference.