A 14 gauge needle is 1.6 millimeters across, it's the standard needle used for 80% of all body piercings by professional body piercers.
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Gauge is the term that indicates the diameter of the needle. Most commonly the needles that are used for medical purposed range from 7 Gauge to 33 Gauge, according to the Stubs scale. 7 Gauge needle will have the largest diameter while as the number increase, the diameter decreases. Therefore the 33 Gauge needle has the smallest diameter. So a 26 Gauge needle will have a smaller diameter than that of the 18 Gauge needle.
Most piercings are pierced with a 16 gauge needle, but if you want to stretch it, I wouldn't go any larger than a 10.
The hole that a needle gun makes at Claire's for ear piercings is typically around 1.2mm or 18 gauge in size. This size is standard for earlobe piercings and allows for proper healing and jewelry insertion.
Butterfly needles come in several gauges - 21, 23, and 25-gauge.
For industrial piercings, a needle, usually 16 gauge, is used. The ear is marked so the piercer knows where to put the needle, and the needle goes through both pieces of cartilage. Then, the bar is inserted through the needle, the needle is removed, and the other end is screwed onto the ball. This video shows how its done. http://www.youtube.com/watch?v=kfPM-esijW
Yes, that's fine. All the professionally done cartilage piercings I have (five) were 16 gauge, and it wasn't like I had to special request that.
a 25 Gauge needle is capable of drawing blood, but i would go with 21 or 23 for withdrawing lots of blood simply because the 25 gauge could get clogged..
14 gauge
It could be used as long as the needle length is approximately 1 1/2 inches long so that it reaches the muscle tissue. The flu vaccine injections are given IM (intramuscularly) except if it is the new intradermal type of vaccine, which has its own delivery system with a very tiny needle injected into the layers of skin. The typically sized needle for IM administration of medication is a 22-25 gauge, 1 1/2 inch IM needle. 23 gauge is slightly larger around than a 25 gauge, so it is possible you could feel it slightly more when inserted. A 23 gauge needle has an outer diameter of 0.02525 inches. A 25 gauge needle has an outer diameter of 0.02025 inches. As long as you are able to correctly measure the proper dosage, it could be used.
Most piercings can be done with any size needle, but most common for a lip is anywhere between 18g and 10g. Most common is 16g or 14g, depending on the piercers preference.