::. FOR REFERENCE

MACHINE ACCESSORIES FOR DRILLING, SPOTFACING, BROACH TAPERING, REBORING AND THREAD CUTTING.

Drilling is a cutting work method, which allows to make holes, enlarge hole diameter or change their shape. Twist drilling is a rough finish process, which often offers poor surface quality and dimensions. Broach tapering allows to refine hole wall surface and improve accuracy. Broach bits are used for flat or profiled surfaces (according to tool design). Tapping tools provide cutting inner threads. Bore operations allow to make holes with very low accuracy allowances, shape deviations, precise surface positioning and asperity parameters for workpieces of any shape. Drilling machines include following types:

-vertical drilling machines
-radial drilling machines
-horizontal boring mills
-coordinate boring machines
-vertical drilling and milling machines
-all-purpose drilling, milling and boring machines

Accessories for workpiece processing in machines of this group include drilling and collet holders, adapter sleeves, boring and tapping heads, standard and inclined drilling jaws, machine vice, two- and three-axis machine vice, precision vice, v-blocks, turning and tilting tables, edge detectors, bushing plates of different types etc.

Self-centering drill chucks are used for securing drilling tools with cylindrical shanks; a drill chuck is installed into machine spindle by means of a cone shank. Drill chucks can have keys or be keyless (these show higher precision and are easier to use). Besides cam holders, collet holders of various designs are widely used. They allow to perform operations with tools with cylindrical shanks up to 20mm in diameter. In these holders collet is the major clamp member, which is designed as a precisely manufactured bushing with lengthwise slots. Collets are elastic and provide exact toll centering.

Adaptor sleeves are also used for securing tools with cylindrical shanks. Morse cone adaptor sleeves are used for bits with cone shanks. Adjustable adaptor sleeves are used in numerical program control machines and automated lines.

In most cases boring bits are installed into boring heads, design of which offers high accuracy of cutting edge positioning, thus providing necessary aperture quality. Boring units allow to secure the cutter in various positions; a boring bar installed into a bore unit allows to bore large diameter holes.

Tapping heads and chucks are used for internal threading; they provide coaxial matching of the tapping tool and the hole, tapper breakage prevention, spindle motion and thread pitch mismatch compensation and ease of use. Tapping tools are installed into fast-change inserts. Machines without spindle counter-revolution require usage of reverse tapping heads.

Processed workpieces are installed into clamp mechanisms, which are chosen depending on required processing precision, workpiece position and manufacturing steps. These can be simple drilling vice of low accuracy and used for draft drilling, or precision machine vice (including side-surface vice), precision angular sine vise, or prism vice for round-shaped workpieces. Two- and three-axis machine and drilling vice and turning and tilting tables are used for securing workpieces in various spatial positions. Hold-down v-blocks are used for securing parts like rotation bodies, crank shafts etc.