Shoutout to the old timer who showed me how to dial in feeds and speeds by ear

For like 5 years I was just using the manufacturer's recommended settings on my Haas VF-2, and it worked okay but not great. Then last spring a retired machinist at a shop in Grand Rapids told me to listen for that specific chatter pitch and back off the feed by 10% until it smooths out. Anybody else still rely on sound over the calculator for good surface finish?

3 comments

3 Comments

the_margaret2d ago

My old Bridgeport had this weird harmonic at 3200 RPM that would show up on certain parts. I spent a whole weekend chasing it with a calculator before the guy next to me just tapped the vise with a wrench and it went away. Been trusting my ears ever since, even if the numbers say different.

the_charles2d ago

You know what, I used to be the guy who would pull up the calculator and insist the numbers were right until I was blue in the face. But then I had a job making these little aluminum brackets on a old Mori that just wouldn't clean up no matter what the feed chart said. Old timer walks by, stops, and says "sounds like you're fighting the machine" and taps the RPM down just a hair by ear. Fixed it in about two seconds. Now I start with the numbers but I definitely listen first and adjust from there. There's something about that sound that tells you more than any calculator ever will.

henry_martinez1d ago

Find taps the RPM down a hair and suddenly it purrs, meanwhile my calculator is sitting there looking stupid. @the_margaret I swear these old machines have a built in "screw the numbers" setting that activates when you're about to lose your mind. I've started bringing a pair of headphones just so I can hear the cut better over the shop radio (which my coworker insists on blasting polka music on).