Reaming Operation which finishes the surface of a cylindrical hole using a multi-edge tool.
Aluminium Non-ferrous metal rarely used pure, generally used in alloys with copper and zinc, for example, to improve its mechanical strength.
Anodization (anodic oxidation) Aluminium surface treatment which forms a layer of oxide that develops on the surface as an integral part of the metal itself, to improve its resistance and provide added protection against corrosion.
Boring Material removal process which increases a diameter with precision finishing in terms of both roughness and tolerance.
Broaching Creation of grooves and teeth inside holes in metal parts for machining (internal broaching) or shaping of the external profile (external broaching). This process is able to produce square, elliptical and hexagonal holes, splines and even very complex contours.
Bronze A copper alloy: it may be "common", containing just copper and tin, or "special", containing other elements as well as copper and tin to improve its mechanical and technological characteristics.
Burnishing (Black oxidation) A surface treatment also known as black oxidation in which a metal is coloured black in order to improve its appearance and protect it from corrosion.
Precision grinding and honing Machining process which reduces mainly cylindrical or spherical objects to the same diameter.
Chroming Surface treatment which coats the metal with a thin layer of chromium to improve its resistance and provide added protection against corrosion.
Hobbing Material removal machining process which uses a tool with cutting edge in line with that of the cavities to cut the teeth of a gear.
Threading Surface material removal machining process used to create a helical ridge on the metal piece (external threading) or a helical groove (internal threading).
Die threading Axial thread-cutting using a multi-edge tool.
Threading with chaser dies Surface material removal machining processes that creates a threading using a multi-edge tool.
Roller threading Process which creates threads by deforming the material.
Drilling Surface material removal machining process carried out to create a hole, which may include the following phases: - centring (alignment with the axis of the hole); - drilling; - widening (increasing the diameter of the hole); - reaming (finishing of the hole).
Deep drilling Drilling operation to create a hole with depth 10 times the diameter of the hole.
Radial drilling Drilling operation perpendicular to the axis of rotation.
Milling Material removal process capable of producing a vast range of surfaces, including planes, grooves and shoulders, using a multi-edge tool of a specific shape.
End milling Material removal process using a disc-shaped tool to produce parallel planes or slots in the heads of screws.
Radial milling Milling operation perpendicular to the axis of rotation.
Knurling A procedure that uses pressure to create grooves and ridges in a chequered or diamond pattern on surfaces. It is used on coins or mechanical pieces such as regulator knobs, crank handles, etc. to give them a rough surface that offers a firmer grip.
Honing A process that super-finishes the surface of a piece to reduce its roughness to a minimum.
Marking A process which uses pressure to mark the metal piece.
Tapping Internal thread-cutting using a multi-edge tool.
Ferrous metals Metals which contain iron and carbon.
Non-ferrous metals Metals which do not contain carbon: copper and its alloys (bronze and brass), aluminium and its alloys.
Nickel-coating Surface treatment which coats the metal with a thin layer of phosphonickel alloy to improve its resistance to wear and provide added protection against corrosion.
Brass An alloy of copper and zinc, it may contain other metals such as lead.
Polygon turning Material removal machining process which produces square or hexagonal parallel planes on the outside of light alloy pieces.
Copper Non ferrous metal unsuitable for material removal machining process.
Roughness The combination of surface irregularities, relatively small distances apart, caused by the machining process, the shape of the tool, non-uniform materials and any vibration during the process.
Roll-Finishing A pressure rolling procedure carried out to improve the surface finish or to create a tougher thread than could be obtained by turning, since this method induces more hardening in the material.
Satin finishing Matt or semi-gloss finishing process for stainless steel, used for reasons of appearance.
Deburring Finishing process which removes the residues from the upstream machining operation.
Grooving Material removal machining process which uses a tool to create circular grooves.
Chamfering Material removal machining process which uses a tool to remove sharp edges.
Slotting Material removal machining process which shapes the insides of through and blind holes.
Flaring Material removal surface machining process. Turning takes place with rotation of the workpiece and generally rectilinear travel of the tool (in contrast with milling and drilling, when the tool is rotated). The edge of the tool penetrates into the workpiece material and removes the surplus (machining allowance), creating a shaving.
ISO UNI tolerances ISO System, Set of standardised tolerances and deviations for shaft-hole fits, adopted by the UNI (Italian technical and industrial standards authority).
Lathe A machine tool very widely used in industry for material removal machining processes (turning) for the creation of external and internal turning surfaces of different shapes, including threaded surfaces.
Automatic lathe Lathes on which the operator only has to make the initial feed and operating control settings. In lathes of this kind, workpiece clamping, tool approach and feed, working stroke start and stop, and bar feed to start machining a new workpiece, all take place automatically.
Automatic multi-spindle lathe Automatic lathes with drive centres, normally with horizontal axis, which house more than one piece-holder spindle (from 2 to 12) which may also rotate at different speeds, allowing simultaneous machining of several pieces.
CNC Lathe Lathes capable of performing complex machining instructions in response to computerised instructions. On CNC lathes, all phases of the operating sequence are completely automatic, both during actual production and during auxiliary procedures (positioning, tool change and adjustment, feeding of the blank and removal of the finished workpiece); this means that during operation the operate has only to check and supervise the machine. The use of CNC lathes saves money above for the machining of small lots of complex pieces which are repeated frequently.
Turning Material removal machining operation carried out with tools, using a lathe: external cylindrical, tapered, flat or faceted turning. Turning may also consist of a drilling, reaming, threading or contouring process; sometimes it may be milling or grinding.
Surface treatments Operations carried out on metals to modify their characteristics, such as corrosion resistance, appearance, colour and resistance to wear.
Heat treatments Operations carried out on alloys, below the melting point, involving heating and cooling to modify their characteristics such as hardness, strength, malleability, etc.
Cleaning surface treatment Operation which removes the dirt which accumulated during the previous machining steps from the materials, preparing it for the processes which follow. The results of this procedure depends not only on the type of solutions used but also the washing methods.
Parting Machining procedure which uses a tool to separate the machined workpiece from the bar-stock.
Knurling A procedure that uses pressure to create grooves and ridges in a chequered or diamond pattern on surfaces. It is used on coins or mechanical pieces such as regulator knobs, crank handles, etc. to give them a rough surface that offers a firmer grip.
Galvanisation Surface treatment which coats steel with a thin layer of zinc to provide added protection against corrosion.