The retention knob is something that is often overlooked, yet it is the most critical connection between your machine and tooling. A question we often receive is ‘How long is a retention knob designed to last?’ A general rule of thumb is that a pull stud has a lifespan of about 3 years. This is for shops that run standard 5 day/week, 8 hour shifts. If the shop is running 24 hours a day, the retention knob is only good for one year.
Using a retention knob that has been marked with a part number, serial number, lot number, and date can help you track the life cycle of the pull stud. At JM Performance Products, we have been manufacturing retention knobs for over 20 years and we laser mark all of this information right on our retention knobs. In the event of a broken retention knob, this information can help you and the retention knob manufacturer determine what may have happened. Other signs to look for on a worn retention knob are wear marks from machine grippers or ball bearings. Also, once a retention knob becomes too fatigued the pull stud can develop cracks. When these signs are prevalent, it’s time to change your retention knob. If a pull stud breaks during engagement, this can damage the work piece along with the machine spindle. Examining your machine’s retention knobs can also help you determine other problems going on inside your machine. A retention knob can show if there are signs of a tool that has slipped in the spindle or if a drawbar needs to be rebuilt. With the average spindle repair costing $5,000 to $50,000, plus machine downtime, the retention knob is an item that needs to be evaluated in your facility.
When is the last time you examined the
retention knobs in your facility?
We will be at IMTS booth W-2197 answering questions on retention knobs and demonstrating our new products. We'll be covering topics on how to reduce machine variables, improving tool life and increasing machine uptime.A JM retention knob laser marked with manufacturing info:
Sometimes it’s really hard to determine if the time, money and efforts of being an exhibitor are paying off. But sometimes, you know you hit a home-run. Sometimes you get a message from a fellow exhibitor with whom you chatted or gave some product, and you know your efforts have been rewarded. Aaron from Swiftcarb sent our sales team such a message. You can read the entire message in TESTIMONIALS on our site, but here’s an excerpt that sure validates our efforts: “…On the second day of the show, we switched out the standard retention knobs that we were using, for JM's High Torque Retention knobs. There was an immediately noticeable change in the pitch of the machining operation, and all 4 of us, with our hands on the machine, could feel the difference in the smoothness of the machining sound. After the part finished, we were also able to notice a smoother wall finish on the part than we were previously getting, and we have no doubt that if given the time, there would have been an increase in tool life as well. “