Device for holding mechanical parts

A device for holding mechanical parts, comprising:

• a slider-holder formed by a body and by a head, both having a central bore in which a first portion of the piece to be held is placed, the piece to be held such that a second portion extends from the head, the head comprising a conical area;
• at least two sliders:
• and
• an actuation element for said sliders;
• wherein at least two lateral bores are formed in the head each bore leading on the one hand into said conical area and on the other hand into said central bore, wherein said sliders are each placed in one of said lateral bores, the sliders being adjusted in the lateral bores in order to be able to slide therein, said sliders exceeding the conical area of said head, the actuation element of said sliders being arranged to displace said sliders in the corresponding lateral bores along an axis perpendicular to a longitudinal axis of the central bore.