The Vergnano Sincro tap series for synchronised tapping S15/BS15 and S70/BS70, introduced in our latest catalogue (issue 42-2007), has now been extended with new types:

• cutting taps with metric fine thread, types S17 and S71
• cutting taps for grey cast iron, types S43, BS43 and S45
• cold forming taps, types S80N and BS80NR.

The new types have been developed in order to fulfill growing industrial demands for higher productivity on a wide range of materials and the increased diffusion of modern CNC machines with synchronised spindles.

Process description

• The rotational and axial movements of the spindle are synchronised through the numeric control of the machine during the entire tapping process
• Specific tapping attachments for synchronised tapping are equipted with micro-compensation (< 1 mm), differenciated in traction and compression. In contrast to standard compensated tapping attachments, in which the compensation extension is large, synchronised tapping attachments can be defined as “almost rigid”. As a result, synchronised tapping is often referred to as rigid tapping
• The micro-compensation reduces the axial forces generated on the tap due to small pitch errors and mechanical play
• The synchronisation between machine, spindle and tap permits high cutting speeds
• Sincro series taps can be used only for rigid tapping. If used with compensated tapping attachments, which allow the tap to free float, the aggressive cutting geometry can generate high axial forces. This may cause the tap to advance more than the requested pitch resulting in oversized threads
• All Vergnano taps can be used for synchronised tapping but the Sincro series is developed specifically for this type of application. This results in higher tool life and higher productivity due to higher cutting speeds

Tap characteristics

• Sincro series taps are produced in top quality powder metallurgy high speed steel, HSSK
• On request, the taps can be delivered with a flat on the shank according to DIN 1835B to be used with traditional tapping attachments. All Sincro series shanks have an h6 tolerance, more precise compared to the h9 tolerance normally used on shanks, necessary for DIN 1835B flats but which also permits use with heat shrinking attachments
• The specific cutting geometry for synchronised tapping allows high cutting speeds
• The reduced thread length compared to standard taps permits tapping of deep holes. This reduction is possible since the tap is guided by the machine and not by the tap itself
• The 40° spiral flute angle (type S70) is ideal for tapping deep blind holes. In addition, the back tapering on the thread reduces the torque during inversion of the tap
• The extended series includes three types of cutting taps (S15, S43, S70) and one type of cold forming tap (S80N)
• Versions with internal lubrification, both axial and radial, are availabe for all types (BS15, BS43, BS70, BS80NR)

Advantages

• Reduced machining cycle times, due to higher cutting speeds
• Increased productivity
• High quality threads

Requirements

• CNC machine with synchronised rotational and axial movements of the spindle
• Spindle with sufficient rotational speed in order to reach the requested cutting speeds also with small diameter taps
• Synchronised tapping attachment with micro-compensation
• In the case of taps with through-coolant, specific spindle and attachment for this application
• In order to work at the requested cutting speed during the entire machining process, the spindle must be able to accelerate to full final speed before the tapping process begins

Range