How to read the specifications of a tattoo machine

Specifications are measurements or declarations about individual components and characteristics: the needle's stroke, the body's weight, the voltage range, the battery life. A machine's behaviour comes instead from the meeting of many of these things, plus the cartridge mounted and the way it is used. That is why two machines with similar numbers can feel different, and two machines with very different numbers can be closer than they seem.

Reading a sheet therefore means looking for the relationships between the data, rather than comparing individual values one by one.

Instead of scrolling the sheet from top to bottom, it helps to group it. The specifications of a tattoo machine fall, in general, into four families.

This includes the architecture (coil, rotary, pen), the transmission system, the motor, the stroke and, when the manufacturer states it, the give. These are the data that describe how the needle moves.

They have to be read together: stroke says how far the needle travels at each cycle, but how that movement is generated and transmitted depends on the motor and mechanics. The same millimetres of stroke, on different architectures or transmissions, do not necessarily produce the same behaviour.

This includes the type of power (cord or battery), the operating voltage range, the battery capacity and runtime, the charging time.

These data also influence one another. The voltage set generally affects the motor's speed and therefore consumption; battery capacity, expressed in mAh, indicates how much charge can be stored but does not coincide with runtime, which also depends on the motor and settings. For corded machines, energy is not a datum of the machine but of the whole formed by power supply, cord and connector.

This groups weight, dimensions, grip diameter and materials. These are the data that tell how the machine sits in the hand.

The measurement conditions are always needed: a weight may refer to the body alone or include battery and cartridge; a length may or may not include the cartridge. A comparison between two values is correct only if they describe the same configuration.

This includes cartridge compatibility, available accessories, replacement batteries or power supplies and connectors. They do not describe the machine alone but what can be paired with it: they often decide more than speed or weight whether a product suits one's way of working.

Same stroke, different characteristics. Two machines declare the same stroke. One has a motor and transmission designed for a more direct movement, the other an architecture with more elasticity. The value in millimetres is identical, but the perceived behaviour may not be. The number describes a distance, not the quality of the movement.

Weight and weight distribution are not the same thing. Two pens of 150 g can feel very different in the hand: in one the battery is close to the part that is held, in the other the weight is shifted towards the back. The sheet reports the total, while balance depends on where the components are placed.

Declared and real runtime. The manufacturer states a number of hours measured in specific conditions, for example at a certain voltage and under a certain load. In real use, with different settings, the result can change. Declared runtime is useful as an order of magnitude and for comparing machines from the same manufacturer, much less for comparing different brands.

Not all the data in a sheet carry the same informative weight. It is worth distinguishing at least three levels:

• Data declared by the manufacturer: stroke, voltage range, runtime, battery capacity, compatibility. They are the most common source and, as a rule, are not independently verified.
• Data verifiable with a measurement: weight, dimensions, grip diameter. They can be checked, but it remains to be understood which configuration they refer to.
• Qualitative descriptions: "soft", "quiet", "balanced", and in part give too. They are useful as a clue, but have no common scale between manufacturers.

Odisage reports the data as declared and flags when a characteristic comes only from the manufacturer. If a datum is not stated, it stays not stated: an empty field is information too.

• 1. Start from architecture and power. They are the two choices that condition everything else: they change adjustments, size, maintenance and how energy is managed.
• 2. Read the movement as a whole. Put stroke, motor, transmission and operating voltage side by side. Ask which are stated and which are not.
• 3. Assess the body together with the conditions. Weight with or without battery, dimensions with or without cartridge, grip diameter and materials.
• 4. Check the ecosystem. Compatible cartridges, replacement batteries and power supplies, connectors.
• 5. Note what is missing or only descriptive. Then place two products side by side with the Compare function, so the data are read on the same parameters.