Three Tips for Threading Success

Often the last step in part production, threading operations can’t be redone or repaired – if it fails, the part is scrapped. To avoid these losses and realize the highest level of threading productivity, you have the make the right decisions about every aspect of the operation. Here are three tips to guide you toward correct choices and profitable threading:

#1: Tool selection and use are critical.

The process of threading begins with making a thread form on a spiral, which usually involves spirals that get smaller and tighter as parts become smaller in diameter – on larger diameters, the spirals get larger or even vertical. To make a proper thread, the tool insert must track the spiral correctly throughout a bore. Start with the proper anvil or helix angle in the toolholder, and if necessary, insert a shim seat underneath the insert to improve tracking, eliminate tool chatter and produce better gauging that creates a better thread.

When it comes to superalloys and other extremely hard materials like carbide or CBN, however, new techniques have been developed to help manufacturers thread workpieces in a hardened state, which eliminates time-consuming thread grinding and the need for potentially thread-distorting heat treatment following machining. To maintain cost-effective tool life, highly precise internal coolant, such as that available from Seco Tools’ Jetstream Tooling®, can control chips, improve surface finishes and stabilize threading without the need for external hoses, fittings and spare parts that diminish productivity and raise costs.

#2: Chip control can make or break threading operations.

Long, stringy chips that wrap around a toolholder can damage the tool's inserts and reduce their functional lifespan. Of course, re-indexing one or more inserts can correct the chipping problem and enable the threading process to resume, but needless re-indexing also wastes tool life. And if chips damage the thread itself, they can doom a part to the scrap pile. Additionally, when a chip becomes stuck inside a part during internal threading, an operator can sustain an injury attempting to fish out the chip and rescue the part, while a part loader or other robot can easily be stopped dead in its tracks after getting tangled up in chips.

Naturally, Jetstream Tooling® serves as an ideal general-purpose solution for chip control in threading operations, but in some materials, including stainless and other challenging steels, advanced coating chemistry and tool geometry can be vital to keeping chips flowing. For example, Seco’s TTP2050 grade offers alternating nano-laminate PVD layers of wear-resistant titanium aluminum nitride (TiAlN) and titanium silicon nitride (TiSiN), while the -A geometry is optimized specifically for effective chip control.

#3: Machine tool defaults may not be ideal for your task.

Machine tools ship with default modes preset on their CNC controllers, some of which produce more threading passes than a job may require. Machines also typically make radial in-feed their default cutting mode, which causes high cutting forces – and the resulting chatter and vibration – due to the insertion of the tool straight into the material. To avoid poor chip control and marred surface finishes, it's important to choose a cutting mode that uses only as much cutting force as the job requires.

Seco has committed itself to helping you resolve threading questions, match tools with specific workpiece materials – especially challenging options such as high-temperature alloys – and troubleshoot causes of chatter and vibration. For the easiest route to threading success, the Suggest tool, part of the Seco website’s My Pages digital portal, produces customized recommendations for threading tasks. And for personalized help, be sure to reach out to your Seco representative or visit SECOTOOLS.com.