REAMING

Reaming is the action of reaming, that is to say precisely machining the interior surface of a hole, a tube or any other hollow part, generally previously roughed out by drilling. Unlike drilling, which creates the opening, reaming aims at dimensional precision, geometric regularity and the quality of the interior surface finish, in accordance with standardized tolerances — the IT grades of the ISO standard, which a straight reamer allows to achieve around grade 8 and a helical reamer around grade 7. It is carried out using cutting tools on their periphery, called reamers, mounted floating in a chuck on machine tools (Lathe, Milling machine, boring machine) or used by hand. In watchmaking, reaming occurs wherever a precise fit is required: jewel seats before Setting (stone/jewel setting), barrel seats, holes receiving pivots or rods. The precision of the operation directly determines the operating Set and the durability of the assemblies: a Reaming that is too wide introduces Set, vibrations and premature wear, while a Reaming that is too tight prevents assembly or causes seizing of the moving parts.