Quick change mandrel for an engine lathe etc

A mandrel for a lathe comprising an adaptor and an insert,

• said adaptor having mounting means for mounting the adaptor on the rotating spindle of a lathe,
• said adaptor having a receptacle for receiving a suitable insert therein,
• said adaptor having an annular reference plane formed in said cavity with a series of projecting ears formed in said cavity in predetermined spaced relationship with said plane an insert for mounting in said receptacle,
• said insert having a reference plane formed by a second series of projecting ears formed on said insert,
• said insert being insertable into said adaptor receptacle until said reference planes engage whereupon the adaptor and insert may be rotated relatively to cause the projecting ears of the adaptor and insert to engage and lock the adaptor and insert together.

A composite mandrel for gripping and clamping a rotatable workpiece suitable for rotation in a machine such as an engine lathe or grinder comprising:

• an adaptor having suitable means for mounting said adaptor on the rotating spindle of said machine,
• said adaptor having a cavity formed therein, said cavity defining at least one reference surface and,
• an insert for reception within said cavity, said insert having at least one corresponding reference surface to mate with the reference surface of said adaptor, said adaptor and insert each having co-operating locking means associated therewith, and locking means being actuated by twisting said insert with respect to said adaptor within said cavity for forcing said reference surfaces together,
• said insert having means for gripping and clamping a suitable workpiece thereon.

A composite mandrel comprising two mating parts which is intended to be mounted on the rotating spindle of a lathe or other similar type of rotating machine,

• said mandrel having the capability of chucking a suitable workpiece thereon for suitable rotation about the rotating spindle axis,
• said first mating part comprising adaptor means to enable said first part to be mounted on said spindle for rotation therewith,
• said first mating part also having a cavity for receiving a second mating part therein,
• said cavity having at least one reference surface formed therein, said cavity having at least one reference surface formed therein, a first series of spaced projections protruding inwardly and axially spaced a predetermined distance from said reference surface,
• said first projections being separated by a series of spaced recesses,
• a second mating part for insertion into the cavity of said first mating part,
• said second mating part having a reference surface thereon defined by a second series of spaced projections which co-operate with the recesses and projections in said first mating part.