Method for forming an internal taper in the walls of a sleeve-like body

Claim 1

A method of forming an internal taper in the walls of a sleeve-like body beginning at one end of said body, said method comprising: mounting said body in an upright stationary position with the end at which the taper is to begin at the bottom; introducing an etching solution continuously to the interior of said body from the bottom to form a pool within the body to which pool the inside faces of the body are exposed; agitating said pool; continuously discharging said solution from said pool through an overflow positioned within said body; moving said overflow vertically during the tapering operation and thus changing the level of the pool surface; and controlling the depth to which the walls are etched by control of the rate of movement of said overflow to provide maximum time of exposure to said solution at the lower end of said body and a diminishing time of exposure at each successive level thereabove.

Claim 2

A method of forming an internal taper in the walls of a sleeve-like body beginning at one end of said body, said method comprising: mounting said body in an upright stationary position with the end at which the taper is to begin at the bottom; introducing an etching solution continuously to the interior of said body from the bottom to form a pool within the body to which pool the inside faces of the body are exposed; agitating said pool; continuously discharging said solution from said pool through an overflow positioned within said body; moving said overflow vertically during the tapering operation and thus changing the level of the pool surface; and controlling the depth to which the walls are etched by control of the rate of movement of said overflow to provide maximum time of exposure to said solution at the lower end of said body and a diminishing time of exposure at each successive level thereabove.

Claim 7

A method of forming an internal taper in the walls of a sleeve-like body, said method comprising mounting said body in an upright stationary position, introducing an etching solution at a plurality of points to the lower end of said body and forming a pool within the body to which the inside faces of the body are exposed, overflowing the solution from the pool at progressively higher levels as the tapering operation progresses, whereby each successive level of the walls is exposed to solution for a shorter time, continuously recirculating solution from its points of introduction through the overflow, and introducing air to the pool to agitate the solution therein.

Claim 8

A method of forming an internal taper in the walls of a sleeve-like body, said method comprising mounting said body in an upright stationary position, introducing an etching solution at a plurality of points to the lower end of said body and forming a pool within the body to which the inside faces of the body are exposed, overflowing the solution from the pool at progressively higher levels as the tapering operation progresses, whereby each successive level of the walls is exposed to solution for a shorter time, continuously recirculating solution from its points of introduction through the overflow, and introducing air to the pool to agitate the solution therein.