Before tattoo machines existed, tattoos were done by hand. Naturally tattoo machines have a speed the human hand can not compete with. The famous inventor Thomas Edison invented a electric engraver approximately around the time of the new century and the machines, were modeled after that with continuing improvements and evolutions. Tattoo machines are an up to date and modern way to apply tattoos. Professional Tattoo equipment and machines greatly aid the artist in applying tattoo ink to the skin, such equipment can be found on any good Tattoo Supply website.
All machines come in different sizes, machines can also be referred to as tattoo guns but generally speaking it is those lacking tattooing experience that refer to them as guns. The machines drive the pigment into the skin by the application of electromagnetic coils, that moves the needle up and down. The evolution of tattooing as a more complicated and precise art form is due to the way the needles, pressure, speed and level of depth can be controlled.
As the endeavor to reach "perfection" in tattooing goes on, the tattoo machine will continue to evolve, and has made great leaps over the decades. There has been much evolution of the modern machine but the basic function of the tattoo machine remains, to put ink on a person. Modern day tattoo machines can now create a great variety of designs according to a persons wishes. Modern day machines don't use just one needle as was the case in the past but a variety of needles to achieve such intricate and variation of design.
Home made tattoo kits should be avoided like the plague, the health risks associated with home made kits are extremely high. Some people think tattoo machines run on a similar principle as a sewing machine, hollowed out needles, and rotating needles going up and down but this is not the case. It is highly recommended to buy a kit from a reputable dealer and avoid amateur and hence dangerous home made kits.