Patent ID: 8297478

Claim:
A powder feed cylinder assembly, comprising: a cylinder having a first end, a second end, a main passage, a first feed channel, and a second feed channel, the main passage extending axially through the cylinder, the first feed channel formed radially through the cylinder at a first axial location between the first and the second ends and in communication with the main passage, and the second feed channel formed radially through the cylinder at a second axial location between the first and the second ends and in communication with the main passage; a bit extending through the main passage and having a first end, a second end, and an outer surface, the outer surface including a helical channel formed on the outer surface of the bit; a center bushing disposed in the main passage between the first and second axial locations, the center bushing having a first axially-extending passage through which a first portion of the bit extends; a first end bushing disposed in the main passage and having a second axially-extending passage through which a second portion of the bit extends, the first end bushing disposed on a first side of and spaced apart from the center bushing; and a second end bushing disposed in the cylinder and having a third axially-extending passage through which a third portion of the bit extends, the second end bushing disposed on a second side of and spaced apart from the center bushing.