Tube expanding apparatus

A method for expanding an outer diameter (O.D.) of an end of a tube having an initial O.D. to a cylindrical shape having a predetermined final O.D. and a significant length comprising the steps of:

• aligning a tube in a predetermined orientation within a tube alignment member;
• securing the tube at a first end within a tube clamp member while leaving the second end of the tube as a free end;
• and inserting a helically fluted spinning tool, while rotating the fluted spinning tool at a predetermined speed, into the free end of the tube along a central longitudinal axis of the tube such that the fluted spinning tool contacts and rubs against the inner walls of the free end to expand an outer diameter (O.D.) of the free end;
• and
• continuing to insert said tool while said tool is rotating into the end of said tube until the O.D. of a significant length of said tube is expanded to a cylindrical shape having said predetermined final O.D.

A method for expanding an end of a tube comprising the steps of:

• aligning a tube in a predetermined orientation within a tube alignment member;
• securing the tube at a first end within a tube clamp member while leaving the second end of the tube as a free end;
• and inserting a fluted spinning tool, while rotating the fluted spinning tool at a predetermined speed, into the free end of the tube along a central longitudinal axis of the tube such that the fluted spinning tool contacts and rubs against the inner walls of the free end to expand an outer diameter (O.D.) of the free end,
• wherein the fluted spinning tool has helical flutes that are grooved into the fluted spinning tool at a depth of about 0.065 inches with a rake angle from about 10° to about 12° .

A helically fluted spinning tool for expanding an outer diameter (O.D.) of an end of a tube having an initial inside diameter (I.D.) and an initial O.D. to a cylindrical shape having a predetermined final O.D. and a significant length, the fluted spinning tool comprising:

• a conical point adapted to insert into a free end of the tube and a neck continuous with the conical point;
• a tube expanding member continuous with the neck and having helical flutes having a working surface O.D. that is greater than the initial I.D. of said end of said tube;
• and a shank which is continuous with the tube expanding member and which is received into the chuck of a drill head;
• and
• a rotator and a displacer operable to rotate said tube expanding member while simultaneously inserting said tube expanding member into said tube a sufficient distance to cause the O.D. of a significant length of said end of said tube to be expanded to a cylindrical shape having said predetermined final O.D.

A fluted spinning tool for expanding an outer diameter (O.D.) of an end of a tube, the fluted spinning tool comprising:

• a conical point adapted to insert into a free end of the tube a neck continuous with the conical point;
• a tube expanding member continuous with the neck and having helical flutes;
• and a shank which is continuous with the tube expanding member and which is received into the chuck of a drill head;
• wherein the helical flutes are grooved into the fluted spinning tool at a depth of about 0.065 inches with a rake angle from about 10° to about 12°.