Old timer warned me about coolant ratio at a job shop in Cleveland

I was setting up a new Haas VF-2 last year and this guy in his 60s who had been there since the 80s walked over. He just said 'your coolant looks thin, you're gonna eat those tool holders in about two months.' I brushed it off because I was running 5% concentration like the manual said. Sure enough seven weeks later I started getting chatter and found the turret had built up rust inside the taper. He was running 8% on all his programs and never had that issue. Has anyone else found that the factory recommended ratios are way too low for real production runs?

3 comments

3 Comments

sam_cooper5d ago

I used to be the guy that followed the manual to the letter on everything. Ran 5% on my first real job at a shop in Akron about ten years back. Started getting weird chatter on a Mazak after maybe six weeks, same as you. Pulled the tool holder and there was that orange crust inside the taper. An old Swiss guy running the machine next to me just shook his head and said 'too much water.' Bumped it to 7.5% after that and never had the issue again. Now I start at 8% on anything that runs more than a shift and adjust from there. The manual is for ideal conditions, not a humid shop floor in August.

wadejenkins5d ago

That old Swiss guy knew his stuff, manuals don't account for real humidity.

knight.uma5d ago

Did he give you his test for checking the mix or just eyeball it? I've seen guys do the shake test or stick their finger in it but that seems like a gamble. Curious if your old timer had a method or it was just years of looking at the shit and knowing.