Method for honing blind bores in workpieces

A method for honing a cylindrical blind bore that is open at one end and closed adjacent to the opposite end comprising providing a tubular honing mandrel, having a first end portion with a substantially cylindrical outer abrasive surface over the length thereof, said first end portion having a substantially conical inner surface, at least one axially extending slot extending through the first end portion and through part of the adjacent portion of the tubular mandrel, an expander member positioned extending through the honing mandrel and having a conically tapered end portion for movement into surface-to-surface contact with the substantially conical inner surface of the mandrel, the method including the steps of:

• programming in a computer controlled honing machine including the tubular honing mandrel, the size of the blind bore to be honed by each honing operation when a honing operation requires more than one pass of the honing mandrel through the bore to reach the final desired blind bore size,
• moving the expander member in the honing mandrel axially in a direction to retract the honing diameter so that the mandrel can be inserted into and through the bore,
• advancing the expander member axially in the honing mandrel to force the conical end portion thereof against the conical inner surface of the honing mandrel to cause the honing diameter of the abrasive surface to expand outwardly to bear against the surface of the bore, and
• withdrawing the expanded honing mandrel from the bore while rotating the honing mandrel to hone the surface of the bore to a programmed size.

A method for honing a cylindrical blind bore that is open at one end and closed adjacent to the opposite end comprising providing a tubular honing mandrel having a first end portion with a substantially cylindrical outer abrasive surface over the length thereof, said first end portion having a substantially conical inner surface, at least one axially extending slot extending through the first end portion and through part of the adjacent portion of the tubular mandrel, an expander member positioned extending through the honing mandrel and having a conically tapered end portion for movement into surface-to-surface contact with the substantially conical inner surface of the mandrel, the method including at least one honing operation including the steps of:

• moving the expander member in the honing mandrel axially in a direction to retract the honing diameter so that the mandrel can be inserted into and through the cylindrical bore,
• advancing the expander member axially in the honing mandrel to force the conical end portion thereof against the conical inner surface of the honing mandrel to cause the honing diameter of the abrasive surface to expand outwardly to bear against the surface of the bore, and
• withdrawing the expanded honing mandrel from the bore while rotating the honing mandrel to hone the surface of the bore,
• wherein the maximum diameter of the outer abrasive surface of the tubular honing mandrel is programmed in a computer controlled honing machine which controls the honing operation, the position of the maximum diameter of the abrasive surface being programmed to occur at the beginning of each honing operation after the mandrel is inserted into the blind bore to a position adjacent to the closed end thereof.