Anyone who works on a brake lathe has experienced chatter. It comes with the territory. Today in Tech Notes, we’re going to look at what causes chatter and how to control it.
First, let’s define chatter. According to the Merriam-Webster dictionary, chatter is a verb that means:
“to vibrate rapidly in cutting, a chattering tool
“to vibrate especially audibly as a consequence of repeated sticking and slipping, chattering brakes”
Chatter, therefore, is not unique to turning brake rotors or drums.
So, what causes chatter?
- The shape of the object being cut on the lathe
- A dull, broken or damaged cutting tip
- A loose cutting tip
- Improper set-up
Take a look at a brake drum. It has a bell-like shape. A brake rotor has a dish-like shape. Both shapes are prone to vibration – or chatter.
To eliminate chatter in this instance you need a brake lathe silencer band (or chatter eliminator band). The most popular brake lathe silencer band are rubber straps that wrap tightly around the rotor or drum. It is essential that these bands be tight on the rotor or drum, for safety as well as for performance. There are, of course, many other styles of silencer bands on the market, but they all work on the same principle; stabilizing the item being machined to reduce vibration or chatter.
Resolving chatter when a tip is dull or damaged or loose is a very simple fix. Replace or simply turn the cutting tip to provide a sharp edge. If the tip is loose, tighten it.
If none of the above work, you're probably dealing with improper set-up. To resolve this, double check your lathe set up. Is everything mounted correctly? Check your arbor run-out. Are your spacers and arbor nuts tight? Have you crossed any threads?
