Question about coolant concentration and tool life

I ran the same job for a year with coolant at 8% and tools lasted about 40 hours. Last month I let it drop to 3% for a week and started getting chatter and breakage after 15 hours. Has anyone else seen a drop this sharp from just a small change?

3 comments

3 Comments

barbarah191mo ago

You think that's bad? I once forgot to mix coolant at all and my endmill turned into a sparkler.

spencer81mo ago

Our 5% mix gave us double the tool life over 3% in our shop.

the_jennifer1mo ago

Yeah that tracks with what our machinist was saying last month. He read some forum post about how a slightly richer mix can actually reduce heat buildup on harder materials. Said he tried it on some stainless jobs and the inserts just kept going. Makes you wonder if the old school 3% rule is kinda outdated for modern tooling.