Finally nailed a tight tolerance part after three failed attempts last Friday

I run a Haas VF-2 at a small shop in Akron, Ohio. We had this aluminum bracket come through that needed a plus or minus .0005 on a bore. My first try last Tuesday came out .001 over and I about lost it. Second try I tweaked the feed but overshot again. Friday morning I came in early, ran a test piece with a new approach using a boring head instead of an end mill. It hit dead center on the money. My foreman walked over and just nodded, said "not bad for a Tuesday." It felt good to get it right after staring at the print for three days. Anybody else have a part that just fought them until they changed their whole setup?

2 comments

2 Comments

miles27725d agoMost Upvoted

Man, I gotta push back on this one a little bit. Switching to a boring head after three tries feels like you made the problem harder than it needed to be. If you're running a Haas VF-2, that machine can hold .0005 all day with a good end mill and proper speeds and feeds. Sounds like you might have been fighting the toolpath or your DOC was off. Boring heads introduce their own headaches, like deflection and setup time. I'd bet you could have gotten it with a solid carbide end mill and a spring pass, but you went the long way around.

mason_lee25d ago

You're not wrong about the Haas holding .0005, but I've seen boring heads save jobs when an end mill just won't cooperate with tool deflection on a deep bore. A spring pass doesn't fix everything if your tool is already walking.