Work out how much neat coolant and how much water to add to bring a sump up to its target concentration. Enter the current refractometer reading, the target and the sump volume.
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Request a Proposal →Maintaining correct coolant concentration is critical for tool life, surface finish, and sump life. This calculator determines how much concentrate or water to add when your refractometer reading is off target.
General machining steel: 7-10%. Aluminium: 5-8%. Stainless and superalloys: 8-12%. Grinding: 3-5%. Always follow the coolant manufacturer's recommendation — concentration too low causes rust and bacterial growth; too high wastes coolant and may cause skin irritation.
Use a handheld refractometer (Brix scale). Take a sample from near the coolant nozzle (not from the sump surface). Apply 2-3 drops to the prism, close the cover, and hold up to light. Multiply the Brix reading by the coolant's refractometer factor (typically 1.0-2.5 — check the product data sheet).
Check weekly as a minimum. Check daily for high-production machines or when running multiple shifts. After heavy coolant loss (carry-out on parts/chips), top up and re-check. A daily log of readings helps spot trends before problems occur.
Measure your current concentration with a refractometer. Enter the current %, target %, and sump volume in litres. The calculator tells you exactly how much concentrate or water to add to hit the target.
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Use the calculator freely. If the result points to a tooling or process problem, we can source the exact carbide tooling you need from vetted factories in China. Compare factory-direct pricing.
Before you commit to a spec, it helps to know what the market pays for it. These are real, publicly listed factory prices — not a quotation, and not a guess.
We source the tool families below direct from vetted Chinese factories, matched to the material and tolerance you just worked out. Every batch ships with its material certificate and dimensional record.
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CHASING SURFACE FINISH OR TOOL LIFE? Coolant is the cheapest lever on a shop floor and the one most often ignored. It is also one of the six things that actually drive your unit cost.
We source carbide cutting tools from China for job shops. We do not own a factory, which is why we can quote your drawing against two or three plants that actually run your material.
Cutting formulas with the units worked through · Speed and feed starting points for all six ISO material groups · How to read a carbide grade past its ISO code. 12 pages.
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