The TD-035.390 feed finger collet is a technical component for the Cucchi Pietro PB40 automatic bar feeder, manufactured with M25x1.5 left-hand thread and 39 mm outside diameter. Its function is to grip the bar, keep it correctly guided and transmit the feed movement generated by the bar feeder towards the lathe. It is used on automatic lathes, CNC lathes and Swiss-type CNC machines, where gripping quality and material stability directly affect production continuity, dimensional accuracy and the regularity of the machining cycle.

During the machine cycle, the collet works as the connecting element between the feeder pushing system and the bar to be fed. The closing action on the material must be stable, repeatable and consistent with the bar geometry, because insufficient gripping can cause slipping, irregular feeding and loss of position, while incorrect gripping may leave marks on the material or create vibration. In Swiss-type CNC applications, where the bar is advanced and supported in conditions that are highly sensitive to alignment, a correctly selected collet helps reduce form errors, surface-finish defects, transmission backlash and micro-movements during the automatic cycle.

The TD-035.390 collet should be selected by considering the Cucchi Pietro PB40 feeder model, bar diameter or profile, compatibility of the M25x1.5 left-hand thread, alignment between feeder and lathe, spindle-line height, condition of the pusher tube, feeder guides and backlash in the feed transmission. Correct matching between collet and material provides smoother pushing, better feed repeatability and reduced machine downtime. In automated production departments, this check is essential to keep the process stable over repetitive batches and to limit scrap caused by feeding errors.

Feed finger collets can be supplied for round, hexagonal or square bars. For profiled bars, grinding is carried out according to the corner dimension rather than a generic diameter, so that the gripping surface matches the real geometry of the material. This dedicated machining is important to prevent irregular contact, loss of centring, vibration and localised wear. For hexagonal or square profiles, correct evaluation of the corner dimension allows the collet to distribute contact more effectively and keep the material stable during feeding, stopping and restarting phases of the bar feeder.

From an operational point of view, the collet should be checked periodically for thread cleanliness, integrity of the gripping surfaces, absence of burrs, abnormal elastic deformation, irregular contact marks and loss of concentricity. It is also advisable to check axial settings, feeder height, alignment with the spindle, pusher tube, bushings and guides, because feeding precision depends on the entire system and not only on the individual component. A worn collet or a collet not consistent with the bar profile may cause discontinuous feeding, noise, vibration, positioning errors and quality problems on the machined part.

The TD-035.390 feed finger collet for Cucchi Pietro PB40 is suitable for machine shops, bar turning companies, CNC departments, maintenance specialists, machine builders, laboratory technicians, process engineers and quality control managers. It is a professional spare part used to maintain the efficiency of the feeder system and to improve continuity, reliability and precision in automatic production. Tadaah offers this component with attention to technical compatibility and application support, helping select the correct collet according to the installed feeder, required diameter, bar geometry and real working conditions.