Abstract: A holder for a carbon arc electrode: the holder having an elongated body with an opening therethrough in which the electrode is positioned, the body having a slot in the lower end thereof communicating with the opening, the opening being defined in cross-section such that the portion adjacent the slot provides opposed uniplanar ledges to either side of the slot, the plane of the ledges being tapered relative to the axis of the opening through the body; a slide block of length less than the body, the slide block being configured to be slidably positioned in the opening in the body, the bottom of the slide block being an engagement with the ledges, slide block having an electrode engaging upper surface which has a taper of the same angle as the taper of the ledges, the taper being oppositely inclined to that of the ledges so that the electrode engaging surface is parallel to the axis of the opening through the body so that the electrode is contacted by increased pressure as the slide block moves forwardly in th