A holder for measuring instruments when measuring the protrusion dimensions of boring machine tool bits. [Features] · Quenching treatment gives the attachment surface (V surface) excellent abrasion resistance. · Two stages can be selected for the dial gauge mounting position. · The perpendicularity of the V surface and the surface to which the dial gauge mounting bracket is fixed is within 5 μm. · Standard equipped with a dial gauge mounting bracket that supports stems of ø8 (diameter 8 mm). · Can be used immediately after purchase. [Applications] · It can be placed on the arbor or head of boring machines to measure or check edged tool protrusion using a dial gauge. · Useful for accurate mounting of edged tools.