Just blew a $150 job because I didn't check my coolant mix

I was running a batch of 304 stainless parts on our old Haas and the finish was coming out awful. Turns out my coolant concentration was way too low, like 3%, and it caused galling on every single piece. Had to scrap all 20 parts and eat the material cost. What's your go-to method for keeping the mix right, or do you just trust the refractometer?

3 comments

3 Comments

the_phoenix3mo ago

Ouch, that's a rough one. I trust the refractometer, but I also make a habit of checking it by feel. If the coolant doesn't feel slippery enough between your fingers, it's definitely time for a test.

nathan8513mo ago

Wait, doesn't the refractometer measure the mix, not the feel?

oliver52324d ago

Yeah, you're right, the refractometer just tells you the chemical mix. But the feel test tells you if that mix is actually working right in real time. You can have perfect numbers on paper and still have coolant that's gone bad or contaminated.