A:Tattoo machines are generally broken into two categories of function. One machine can be set up as a machine used to create the outlines of a tattoo design, whereas another machine might be set up as shader and used to color in the tattoo. The primary difference is the speed at which the needle bar moves up and down while penetrating the skin. The secondary difference pertains to needle depth.

As a Rule of Thumb:
1. The gapping between the contact post and spring needs to be a nickel width (1.85mm) for shading and a dimes width (1.25mm) for lining.
2. To Set the gap hold down the armature bar ( see diagram above) with your finger and turn the plastic screw until you can move the contact post, adjust the contact post to the proper gap release the armature bar then be sure to tight up the plastic screw again.
3. You will run the power supply slower (about 6.5 - 7 volts) for shading and faster (about 7 - 9 volts) for lining.



Liner
A liner typically runs faster and delivers more of a punch. The faster speed compensates for the speed at which the artist moves their hand along a tattoo. When lining, you’re drawing one line through a certain distance in the skin. You want the needles moving up and down very quickly so that on every strike they are puncturing the skin straight down, delivering ink, then pulling straight out. Imagine poking a needle into a block of cheese, then trying to draw a shape. It can’t be done because you can’t move the needle while it is imbedded in the material. You have to pull it all the way out before you can move further down the line. A tattoo liner machine moves the needle group up and down very fast so that you can move your hand freely without snagging the skin. Liners are set up to deliver maximum ink in a single pass. Multiple passes with liner machines can easily damage tissue and cause scarring because the needles are moving so fast and hitting so quickly that they can literally tear the skin after a couple passes in the same area.

Shader
Tattoo shader machines generally run slower and back off easier (or “hit” softer) because they are intended to make more passes over a single area of skin. Shading is a slower movement of the hand and machine, and the shaded area of skin is subject to more time under the tattoo needles. Shader machines often use larger coils and there are many opinions on why. Common belief is that the larger coils are more efficient at moving larger needle groupings up and down. The theory is that a large stacked needle group such as a 25 magnum is heavier and also takes more force to puncture the surface of the skin than something like a three tight and therefore needs more electricity moving through the coils to keep the needles positioning up and down at a reasonable speed with out turning your power supply up. Larger coils can handle this extra energy and dissipate heat, while also dampening vibration, but their use is debated among tattooers and depending on preference some choose to run standard 8 wrap coils on all their machines. It’s really a matter of personal opinion and what that person likes.