Thread rolling hard materials isn’t always impossible.
Because hardened metals don’t flow easily to fill die threads, they often require a thread cutting process to manufacture.
There’s also the risk of breakage — some materials, especially aerospace metals, are simply too brittle to be thread rolled.
Typically, 150 kilopounds per square inch is the cutoff for thread rolling. These materials are just too strong. However, new alloys are changing the way thread rolling works.
Eco Brass: Strong, Lead Free, and Environmentally Friendly
A new alloy developed with 21st century manufacturing in mind, Eco Brass is a high-performance, lead-free brass material with high strength and corrosion resistance. It also offers a worthy substitute to stainless steel, with resistance to stress cracks and brittleness.
Eco Brass is an alternative to brass materials that meets new ordinances like the Safe Drinking Water Act, which limits the amount of lead content allowed in water. Eco Brass can be used in pipes, fittings and fixtures that are under this ordinance.
Because it is less ductile than previously used leaded materials, however, it is more challenging to thread roll. Previously it was not possible to thread roll Eco Brass successfully, but CJWinter’s team developed a process to roll parts with 16 threads per inch (TPI) or finer.*
The Process
To properly handle the Eco Brass, CJWinter uses a radial pneumatic attachment. This allows for quick, precise adjustment of the pitch diameter and penetration rate in the alloy, which is critical for rolling this particular metal.
The radial method is ideal in allowing for displacement of the no-lead material in an even, balanced flow. With the pneumatic attachment, machine operators are also able to independently fine-tune the material flow rate.
Tips and Tricks: Lead-Free Brass
Eco Brass offers unique advantages as well as particular challenges. In working with this new alloy, our team has learned some special tricks to help handle it best:
- CJWinter thread rolls work well for Eco Brass. If you have a full thread and are struggling with tearing/flaking at the major diameter, try experimenting with thread rolls designed for burnishing crests.
- Good cutting oil is key. A good mineral base oil with extreme pressure additives works well in our shop — in fact, we find it makes all the difference to our process.
- Make sure you have a good blank available before rolling.
- A 3:1 ratio is required between the blank diameter and the major diameter. Don’t forget double check your blank diameter — you’ll need to hold blank diameter within 0.0005.”
From specialty alloys to traditional materials, our team handles it all. Learn more about thread rolling materials and the advantages of thread rolling in our eBook, “Thread Rolling vs. Thread Cutting,” or reach out to the team today!
*CJWinter is continuing to develop this process, now working to meet 14 TPI or courser.
