It has long been established that
Mini = bore of no more than 1/2"
-or- chamber dia. of 3/8" or less.
A long time ago, Terry C. came up with some reasonable size classes and names for them. I never saw any disagreement with his list which follows:
Micro = bore of no more than firecracker caliber (.312")
-or- chamber dia. of 1/4" or less
Nano = bore of no more than BB caliber (.177")
-or- chamber dia. of 3/16" or less
Pico = bore of no more than 1/8" dia.
-or- chamber dia. of 1/8" or less
These are simply general guidelines to help get these mighty mights sorted out. They are not rules; do not consider them as such.
Come on Victor, it's not really fair to call that collection of stuff, bungee corded together, a lathe. Besides the only "turning" it is capable of doing is revolving the work. Do you see any lathe tools, cutters? Come on, the tail stock is a dead center made from a piece of 3/8" all-thread with a point filed on one end and the other jammed into a chunk of plywood. Do you see a saddle, a tool post, a cross-slide or a gear change lever anywhere?
These 3 pics are shown to see how easily you can get started on your own mini, micro, nano or pico cannon or mortar! Do it; have some fun!!
Tracy
The Low carbon steel spinning device.
A crude non-lathe, a simple sketch, a small piece of low carbon, black marker coated, steel rod and a few measured scribe marks is all you need to get started. Oh, and a file, too.
I used a 3/4" wide, cross-cut mill bastard file at first for all the rough stock removal, then smaller files with finer teeth, single-cut types.