Linear tubular motor magnetic shaft sleeve

A method of assembling a shaft of a magnetic motor, comprising the steps of:

• providing a plurality of magnets;
• providing a plurality of pole pieces;
• stacking said magnets and pole pieces to form a subassembly having an outer surface of a first diameter;
• providing a precipitation hardenable chromium-nickel-aluminum stainless steel sheet material;
• forming said stainless steel sheet material into a tube;
• drawing said tube to form a precision stainless steel tube having an inner surface of a second diameter, said second diameter being greater than or equal to said first diameter;
• heat treating said precision stainless steel tube so as to increase both a hardness and a magnetic permeability of said precision stainless steel tube to form a stainless steel tubular sleeve of a Rockwell C hardness of at least about 40 and a magnetic permeability of at least about 100;
• and
• inserting said subassembly axially into said sleeve;
• thereby forming a shaft for a magnetic motor.