Controlling Brake Lathe Chatter

Brake Drums, because of their dish or bell-like shape, have a tendency to chatter. This can result in a wavy or chatter finish. The noise, too, is very objectionable. Chatter can be controlled by being assured that the vibration dampener supplied is securely wrapped around the outside of the brake drum.

Next in order is chatter due to dull, broken, chipped, or improper tool bits. Always use tool bits supplied by the original manufacturer, as they are designed to do a specific job. Using a Negative Rake tool bit on a machine that is made for Positive Rake bits can cause chatter and poor quality finish. All Kwik-Way Brake Lathes require Positive Rake Bits. Mount them with the "pointy" side up.

Carbide tip being loose on shank will also cause chatter. It is IMPORTANT that the screw holding carbide bits actually holds the tip firmly.

When either rotating or replacing carbide tips, it is important to have a clean flat surface for the tip, otherwise, the carbide tip will crack or cause chatter.

Positive Rake vs Negative Rake Brake Lathe Bits

We believe that POS rake is better. It allows for faster cutting because of the way the chips come off you can go faster and still have a quality clean cut. With NEG rake you either have to do more passes or cut much slower to get the same results.


Here is an illustration of the difference. I've seen claims about NEG rake bits being "more durable". The bit lasts longer because you have more usable cutting sides (6) NOT because it is more durable. The material used for both bits is the same material. With a POS rake bit, you are actually "cutting" not unlike whittling with a knife while NEG rake is more like "scraping" the surface. Because the material being removed has less room to move away from the surface it creates more force against the cutting bit causing more vibration, especially at higher speeds. This same action can affect the quality of the surface left behind (chatter). For these reasons we at Kwik-Way have always preferred POS rake cutting

A common issue we have gotten support calls about is bad chatter when using a Kwik-Way Machine. We then discover the caller was using NEG rake bits in our POS rake machine or they have mounted the bit on the tool backward. Both of these conditions will cause bad chatter and a terrible finish.

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