Chasing a ghost offset for 6 hours, it was a worn keyway

I was dialing in a part on our 2015 Haas VF-2 here in Phoenix and kept getting a .003 inch shift on the same hole pattern every run. Checked tool holders, spindle runout, even swapped the work offset values a bunch of times before scratching my head. Turned out the drawbar keyway was worn just enough to let the holder spin a hair, anyone else ever waste a full day on something that dumb?

2 comments

2 Comments

bennett.evan1mo ago

Man, six hours on a worn keyway is brutal. I'm just picturing you standing there staring at the offset page like it's gonna confess to you. That machine's been in the Phoenix heat long enough to have its own opinions, I swear. But hey, at least it wasn't a whole spindle teardown, could've been way worse.

karenh561mo ago

That keyway wear story sounds pretty specific, but honestly I would have checked the spindle and holders first too. Six hours on a ghost offset doesn't mean the keyway was the only problem, it means the machine is getting old enough that other stuff is going to start failing too. A 2015 VF-2 in Phoenix with that heat and dust, you're lucky it wasn't a bearing or a coupler. The offset chase is just the symptom, the real issue is you probably skipped the cheap fix early on, like checking the pull stud condition or the taper cleanliness. Next time you get a random shift, look at the mechanical bits before you blame the control, that saves you the headache.