inside turning

[Nine]

hey im extremely new to machining so this is going to be a newbie question...

i need to accurately turn down 3 different measures on the inside of a hollow aluminum stock about one inch inner diameter and 3-4 inches long, is this even possible on a lathe? and how would i do it?

its for my highschool metals class so i dont have access to a lot of high end machinery...

also i was wanting to make a custom paintball barrel, how would i make the inside perfectly striaght?

[HuFlungDung]

Yes, it is possible to bore 3 different internal diameters. Its maybe a tough "first project" for you, but you will need a set of telescoping gages so you can measure what you've cut. You'll also need a good understanding of the correct tool geometry, and a boring bar to hold the tool correctly.

A custom paintball barrel, would likely be lapped or honed to perfection. Reaming would maybe get you close, but even that may leave some slight toolmarks that you would want to eliminate.

[ViperTX]

You might also want to chase down some centerless ground tubing...I suspect that it's available in the diameter of most of the paintballs....you can then use Hu's method to hone the surface to perfection. Also look at any gunsmith bore drills....

[ViperTX]

Oh, technique...the tubing is held in a 3 or 4 jaw chuck...you could also add a steady rest. the drill, hone would be in the tailstock.