Talked to a retired tool and die maker about my speeds and feeds

I was at a local machining supply place last Tuesday picking up some end mills, and there was this older guy waiting for his order. He saw the brand I was buying and asked what I was running. When I told him I usually ran my 1/2 inch carbide at 8000 RPM with a 0.003 chipload on aluminum, he just laughed and said I was leaving money on the table. He pulled out a slip of paper and wrote down a formula for determining optimal chipload based on material hardness and tool deflection, not just the book numbers. I tried his numbers on a job that afternoon and cut my cycle time by almost 20 percent without any chatter issues. Has anyone else got a tip from an old timer that completely changed the way you set up your toolpaths?

2 comments

2 Comments

emma_dixon701mo ago

Did he account for tool sticking out of the holder length?

the_richard1mo ago

Wait, 20 percent? That's insane for just a chipload tweak - I've been running basically the same numbers for years on my Tormach and never thought to question the book values. The fact he worked out tool deflection into the formula is wild, like how many crashes could I have avoided if someone had just scribbled that on a napkin for me back when I started? I'm half tempted to go hang around that supply place more often just hoping he shows up again.