Old-timer changed my mind about climb milling

At a shop in Detroit, a guy running a 1980s Matsuura told me climb milling was fine for light cuts, but I was wrong to use it on a 3/4 inch end mill in 4140. He showed me how the tool deflected and left a bad finish on his test piece. Anyone else have someone prove you wrong with a simple setup?

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2 Comments

davis.emma1mo ago

Honestly, that deflection test he showed you is wild. I would have bet money climb milling was always better for finish, but seeing the actual cut quality change like that is a real eye opener. Ngl, I've been guilty of just assuming climb cut is the magic bullet for everything, and it sounds like this guy has the real world evidence to back up his point. The way a tool walks in the cut on a heavy pass like that is something you kinda forget about when you're just looking at speeds and feeds on paper. It makes total sense that conventional milling would put that pressure in a better spot for a big end mill in hard material. I bet that lesson is something you won't forget anytime soon, huh.

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kaiharris1mo ago

Nah nah nah, you nailed it. Seeing that video of the tool walk is the kind of thing that sticks with you way more than any textbook ever could. That real world proof is hard to argue with.

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