Tramp Oil Removal

Removing Tramp Oil from your CNC sumps is a key to good maintenance practices, and prolongs coolant life, performance and coolant quality. Our friends at have some great products we have seen in the field many times. Zebra has permitted us to share this blog post, and we are pleased to share it with you.

Author: Bill Burkey

Tramp Oil Skimmer, Tramp Oil Coalescer, Tramp Oil Removal

Tramp oil originates as lubrication oil seeps out from the slide-ways and washes into the coolant mixture, or as the protective film with which the steel supplier coats the bar stock to prevent rusting, or as hydraulic oil leaks. In extreme cases it can be seen as a film or skin on the surface of the coolant or as floating specks of oil. Tramp oil is a contaminant and a potential pollutant if not dealt with properly. What is tramp oil?

What is Tramp Oil?

Tramp oil or sump oil is unwanted oil that has mixed with cutting fluid (also known as coolant, lubricant, or metalworking fluid). It is generated as a byproduct during metalworking operations.

Oil Skimmers and Coalescers

Tramp oil skimmers are used to separate the tramp oil from the coolant. These are typically slowly rotating disks, tubes or belts that are partially submerged below the coolant level. As these moving parts rotate through the coolant, tramp oils cling to them and pass a tramp oil separator or wiper before returning to the coolant sump. These wipers also direct the tramp oil to a container where it is collected for disposal.

To remove tramp oils Zebra Skimmers manufactures tramp oil disk, tube, and belt skimmers as well as the Muscle™ coalescer that use floating oil skimmers for tramp oil removal from the surface of metalworking coolants. All Zebra tramp oil skimmers are designed as simple, trouble-free, economic solutions for removing free floating and mechanically dispersed tramp oils from individual machine sumps. Based on gravity flow and coalescence, Zebras disc, tube and belt skimmers can reduce tramp oils to less than 1% in a single pass.

All Zebra tramp oil skimmers extend the productive life of soluble oil, semi-synthetic and synthetic coolants, as well as the cutting tool. All Zebra Skimmers products are backed by a minimum 1 year warranty.

Benefits of using Zebra Skimmers tramp oil skimmers:

  1. Most inexpensive way to remove oil from coolant
  2. Reduces bacterial growth and foul sump odors
  3. Prolongs coolant life, reducing raw material costs
  4. Extends tool life and improves part quality
  5. Prevents plugging of spray heads and filters
  6. Reduces tramp oil disposal costs
  7. Minimal maintenance