Chimpbreakers vs. Knuckledraggers -

When deciding on a roughing end mill, both the Chimpbreaker and the Knuckledragger have common geometries. Both break down chips into smaller pieces that do not accumulate as fast as larger chips do, requiring less machine downtime for waste removal. Time is money and we all know that when a machine is not running, you are not making money. Roughers not only reduce machine downtime, they also minimize cutting forces exerted on a tool during machining, extending tool life. So what are the distinct differences between the two and what’s the best tool for the job?

Comparison of Knuckledragger and Chimpbreaker edge profiles.

Distinct differences.

Notches on the Chimpbreakers are offset to enhance surface finish on the part. This works by ensuring that following flutes clean up any marks or extra material left behind on the first pass leaving an acceptable finish on the walls of the part. In addition to improving chip control, these tools reduce cutting resistance which decreases heat load within the chips.

Knuckledraggers are also great for hogging out a great deal of material, but do not feature the offset geometry. Due to the profile on the cutting edge, tracks along the wall of your part can be left behind. When finish is important, a final pass with a finishing tool is required. The Knuckledraggers are built to withstand harder materials and an ability to run higher chip loads, but does cause a lot of heat and friction requiring a flood coolant to be used while running this tool.

When choosing between the Chimpbreaker and the Knuckledragger, the main question to consider is the surface finish. The Chimpbreaker will produce a smooth finish on the surface of your job, while the Knuckledragger will leave behind tracks requiring a finishing tool if a smooth finish is desired.