You should run your machine between anywhere from 4 - 6 Volts, but there are other variables that come into play when it comes to the smooth running of your machine. You will want to of course make sure that your armature bar/rear spring is properly adjusted for lining, make sure that there is clean contact with your front spring to the contact screw and sand the front spring with a metal grade sandpaper if need be. It's better to have a digital power supply, as this will allow you to more precisely set the voltage of your machine.
you should get a tattoo of your friend with a gun in is hand.
A tattoo machine's speed is so very widely variable that an estimate would do no good. You could use a weak coil machine with a lot of spring tension on a low power source and it will go really slow. But say you use a double contact liner at high power and it goes fast. Even a single machine can be a slow shader or a fast liner. You'll never find a straight up answer, sorry.
The thickness of a dime from tip to needle points, that's without the machine running. Tip: we don't call them "guns" they are "machines", novices who don't know better call them "guns".
Tattoo guns are not firearms.
Yes you can be arrested for having a tattoo gun, unless you are a licensed tattoo artist or legally can pierce skin it is illegal.
no
It is called a machine, not a gun.
Someone looking to purchase a tattoo gun could do so from startertattookit website. Also, someone could purchase a tattoo gun from the sites lightinthebox or tattoomachineequipment.
don't do it
Professional tattoo gun kits can be purchased from KillerInkTattoo and TattooKit. Tattoo kits can also be purchased from online retailers, such as Amazon and eBay.
just a little bit so you can see it
just buy it. Its too complicated to make.