Machine Stroke: EXPLAINED
New artists often struggle to get clean lines and smooth shades. Picking the right stroke length is the difference between a busted tattoo that can’t be fixed and a tattoo composed of crisp lines and flawless blending.
Using the wrong stroke can lead to:
- Needle stick injuries
- Ink pooling on the skin and covering your stencil giving you shaky lines
- Needing multiple passes to form a line
- Patchy shading and colour packing
- Destroying the client’s skin
Keep reading to discover which strokes produce ultra-smooth black and grey, perfect one-pass lines, and gorgeously packed colour.
What is machine stroke? A tattoo machine’s stroke, or “throw,” is the distance the armature bar travels from its most upright position to its most down position. In rotary machines, the stroke refers to the amount of travel required for one rotation. The further the bearing is away from the centre of the cam, the longer the stroke.
This is different from needle depth, which refers to how far the needle hangs out of the tube. Machine stroke is not affected by needle depth. (However, you might decide to change the machine stroke to accommodate a different needle depth.)
You’ll find tattoo machines that have various size strokes or have the ability to adjust the range within a certain amount of stroke size (for example 1.8mm-5mm).
- Short Stroke: 1.8 – 2.5 mm. Short stroke machines move faster because they have less distance to travel in each up-and-down motion.
- Medium Stroke: 3.5mm. This is widely used by tattoo artists. If a tattoo machine is not adjustable, it most likely will come with this stroke length, or one very close.
- Long Stroke: 4mm+. Long stroke machines hit harder because they have more space to “wind up” before hitting the skin.
Why is machine stroke important? The machine stroke determines:
- How hard the machine hits. (A longer stroke gives the needle more momentum because it travels a longer distance in each up and down motion. This gives the machine more power, allowing you to use larger needle groupings more easily. However, increased power causes more trauma to the skin.)
- How fast the needle moves. (How quickly the needle moves in and out of the tip.)
- Your max needle depth. (A short stroke limits how far your needles can stick out. The needle’s depth must be short enough so that it is able to reach the ink inside the tube’s tip in each up-and-down motion.)
When to use different strokes:
A shorter stroke (1.8-2.5mm) is good for applying soft black and grey. This style often requires multiple passes to build up layers of ink. The softer-hitting stroke allows you to create these layered, smooth blends without chewing out the skin. A short stroke cannot be used for lining. It won’t have the power to push the lines properly, and if you set the needle too deep it will not fully retract into the tube each cycle. This prevents the needle being replenished with the tube tip’s ink, which makes getting solid lines in a single pass almost impossible. Additionally, lining requires the needle to hang farther out of the tube (for improved accuracy), which you can’t do with a short stroke. This leads to ink pooling on the skin and covering up the stencil.
A medium stroke (3.5mm) is best for packing colour and blending. A medium stroke has enough power for lining with smaller needle groupings, but it will struggle with larger ones. You can also do some black and grey (but not ultra-smooth portraits that require several passes).
A longer stroke (4.0+mm) is typically only used for lining, as it packs in ink with hard-hitting strokes. It can push large needle groups into the skin with ease, and allows you to hang the needle farther out of the tip, which provides greater accuracy when you’re lining. However, this quality makes it a bad choice for shading, which requires multiple passes. Longer strokes make it nearly impossible to get smooth blends, and the multiple passes shading requires will over work the skin and possibly leave scarring.
Shorter Stroke (1.8-2.5mm)
Soft black and grey, blending colours
Medium stroke (3.5) “Standard”
Packing colour and shading, performs well for both lining and shading
Longer stroke (4.0mm+)
Note: Machine Stroke can be easy to mix up with “needle depth.” If you use a short stroke but decide to increase needle depth, the short stroke will be too short to pull the needle all the way back into the tip. If the needle doesn’t go back into the tip/cartridge, then it wont pick up any ink and it won’t put any in the skin.
The new needle depth needs a longer stroke that will be able to pull that needle all the way back into the tube. The longer stroke will return back into the skin at the same depth of the short stroke machine, except this time, it’ll have ink on the needle. If you do not make this adjustment, your needle will not reach the ink. This will result in weak colours, weak lines, and a patchy distribution of ink (which will only grow more noticeable when the tattoo heals).
My needle is moving in and out of the tip on a short stroke but isn't picking up enough in. Why not?
While you might just need a simple refill, the problem could be how you're holding the machine. With a very small stroke, the needle is barely retracting back into the tip. If you're holding the machine at a tilted angle, then the ink might be further back in the tip than your needle is able to reach. When using a short stroke, hold the machine vertically when possible. That allows gravity to move the ink closer to the very edge of the tip, where the needle will be retracting. Now the ink is back in reach of the retracting needle, ready for use.
Adjusting Your Machine Stroke
What stroke does my machine have? The machine’s stroke or possible stroke range will be listed when you buy your machine. Some machines can be adjusted and others cannot. You will need to know this about your machine before purchasing.
Why is an adjustable stroke important? As a tattoo artist, you will need to have a short, medium, and long stroke available. If your tattoo machine does not have an adjustable stroke - or you don’t know how to properly change the stroke - you will have to buy three separate machines, which can be costly.
How to change your stroke:
- To change the stroke on a coil machine, you will need to turn the front contact screw. By having the screw “back out,” you will make the gap larger, resulting in a bigger stroke. However, this will change the speed of your machine.
- To change the stroke on a rotary machine, you can buy different cams and centers, as this will make the length of each rotation longer (lengthening the stroke of the machine as a result).
Note: Coil machines have “give,” or that “bounce back” feeling when the needle hits the skin. This quality can often be adjusted. Rotary machines have a “direct drive” without the extra give.
A longer stroke on a hard-hitting machine with some give will have less impact on the skin. This means a coil machine is more forgiving if you accidentally go too deep in the skin. As a result, coil machines have a small margin of error that rotary machines do not.
Caution: Pulling lines with a longer stroke
If you are using a longer stroke, remember that the needle will be in the skin for a longer amount of time and will be hitting the skin harder (even if your machine has a good amount of ''give''). This causes trauma to the skin. When you're pulling a line while using a very long stroke, you will need to work fairly quickly to prevent the additional trauma caused by overworking a small area.
Practice Makes Perfect
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