The 035.290 bar pusher collet is a technical component for Cucchi Pietro PB30 automatic bar feeders, manufactured with M18x1.5 left-hand thread and 29 mm outside diameter. Its function is to grip the bar, guide it correctly and transmit the feed movement generated by the bar feeder towards the lathe. It is used on automatic lathes, single-spindle lathes, multi-spindle lathes, CNC lathes and Swiss-type CNC machines, where feeding stability, gripping quality and correct material position in relation to the machine axis are essential to maintain production continuity, dimensional accuracy and machining-cycle reliability.

During the machine cycle, the collet works as the connecting element between the feeder pusher tube 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 mark the material, generate vibration or cause sticking. In Swiss-type CNC machining and in cycles on single-spindle or multi-spindle lathes, where the bar must advance regularly without unwanted variations, a correctly selected collet helps reduce form errors, surface-finish defects, transmission backlash and micro-movements during automatic feeding.

The 035.290 collet should be selected by considering the installed Cucchi Pietro PB30 bar feeder, nominal or real bar diameter, material profile, M18x1.5 left-hand thread compatibility, 29 mm outside diameter, spindle-line height, alignment between bar feeder and lathe, condition of the pusher tube, guides, bushings and backlash in the feed transmission. The bar size must be checked carefully, because the correct match between collet and material directly affects gripping quality, dragging continuity, cycle stability and vibration reduction. Correct matching provides smoother pushing, better feed repeatability and reduced machine downtime.

Bar pusher 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 on the contact surfaces. For hexagonal or square profiles, correct evaluation of the corner dimension allows the collet to distribute the grip more effectively and keep the material stable during feeding, stopping, restarting and bar-change phases of the feeder.

From an operational and maintenance point of view, the collet should be checked periodically for cleanliness of the left-hand thread, 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 interaction of all these elements and not only on the individual component. A worn collet or a collet not consistent with the bar profile may cause noise, vibration, discontinuous feeding, positioning errors and quality problems on the machined part.

The 035.290 bar pusher collet for Cucchi Pietro PB30 bar feeders is suitable for machine shops, bar turning companies, CNC departments, single-spindle and multi-spindle lathe production, 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.