GB549407A - Improvements in the setting of diamond or sintered or fused carbide or like hard dies - Google Patents

Abstract

549,407. Drawing dies; die-holders; chucks. JEARUM, F. C., and GRODZINSKI, P. Aug. 26, 1941, No. 10854. [Classes 83 (iii) and 83 (iv)] Diamond and like dies are mounted in holders such that axial adjustment of the die in the holder controls the supporting pressure upon the die. Such holders may be used both during drilling the die and also during drawing or special holders may be used for each purpose. The diamond is first provided with parallel faces a on which the ends of the axis are indicated. It is then ground to truncated conical shape d, Fig. 3, and mounted in a corresponding socket e. A screw-cap f with a spigot engaging the die controls the axial position and consequently the circumferential pressure. Both parts are recessed for engagement with the spigot f<SP>2</SP> of a face plate on which the holder is mounted by screws h. Observation openings e<SP>3</SP> are provided and when the die is only rough ground, spots are polished that are located at the openings to secure the necessary transparency. When special holders are provided for use during drawing these are neither provided with the spigot recesses nor with holes for the screws. In cases when the diamond is not suited to the conical form a split conical adapter with a polygonal recess to suit the diamond is employed. The diamond in the holder may be drilled simultaneously from both sides by reciprocating the holder between axially fixed high-speed drilling needles. Alternatively the die is rotated but is fixed axially and non-rotating drilling needles are reciprocated with independent controls. The holders may be of stainless steel and be lined thinly with copper; aluminium or copper-aluminium alloy or like bedding material. Dies of double conical or pyramidal form may be employed the cap of the chuck thus having a corresponding recess.