TECH ARTICLE # T019

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The drilled only and slotted only rotors tend to have significant differences, which are combined in the drilled and slotted rotors to help boost their functionality significantly. The drilled the only rotor has been designed to allow air ventilate via a series of holes that allow water, steam, and debris escape; this makes them the best rotor for wet environments.

The introduction of slotted and cross drilled rotors has left technicians asking the question “Can they be machined?” The answer is “Yes – but there are some important things to remember”.

When machining any disc rotor it is important to make sure that all the mounting faces are clean and undamaged on both the rotors and the tooling. Always make sure that the tool tips are sharp and setup directly opposed to each other.
When machining slotted or cross drilled rotors it is extremely important to remember to always use the slowest feed rate and take the smallest cut.

Machining Drilled And Slotted Rotors Calipers

DO NOT take 1 cut to clean up the disc and then a fine finishing cut as you will damage both the disc rotor and your tool tips. If you need to take 5 or so fine cut passes to clean up the face of the disc then that is ok.

Once you have finished machining the disc rotor, very lightly use 240 grit emery paper to smooth off the fine grooves on the face of the disc rotor. Clean the friction faces with a suitable cleaner like liquid acetone or brake clean. Never use petroleum or silicon based cleaners as they will leave a residue on the disc rotor that will impede brake performance.

Machining Drilled And Slotted Rotors

Remember Always check rotor thickness & replace if on or under minimum thickness after machining.

Machining Drilled And Slotted Rotors Pads

Technical Support
Disc Brakes Australia