Compact and heavy-duty machine, made up mainly of a single pneumatic operating unit and suitable for threading the fork stem. The machine incorporates a special fork-housing carriage and a clamping device with “ V” shaped jaw compatible with all diameters. The machine is suitable for all fork models, including suspension types. The automatic carriage is controlled pneumatically and fitted with rotating threading head system through chasers. Possibility of threading both painted and unpainted forks, with adjustment of thread size.