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I swore off check probes on castings after one bad job, then a guy in Dayton showed me what I was doing wrong
Bought a used Renishaw probe off eBay for $400 about 8 months ago and it scrapped two aluminum housings on the first run, so I pulled it and went back to edge finders for everything. A setup guy at a job in Dayton watched me indicate a fixture for 20 minutes and asked why I wasn't using it, then showed me my stylus was running 0.003 out from a bent tip I never checked. How often do you guys re-tram your probe stylus, and is there a cheap way to check it besides running a ring gauge?
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julia_lee11d ago
How did the guy in Dayton actually catch the runout though, was he sweeping the stylus with a tenths indicator on the shank or did he have some trick for checking the tip itself? I've got a spare stylus sitting in a drawer that I don't trust and a ring gauge is like $80 which feels steep for something I'd use twice a year. Wondering if a simple pre-travel test on a known block would show a bent tip or if that only catches bigger problems. Seems like a bent tip that small would still trip the probe fine, just in the wrong spot, which is exactly the kind of thing that eats a part before you know it.
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kim_west11d ago
Ran into the same thing with a used probe I bought off eBay, guy swore it was dead nuts but my numbers were drifting like crazy on bores that should have been cake. Turns out the tip was bent just enough that pre-travel looked fine on a block but shifted once the stylus hit from a different angle, which is the sneaky part. So yeah, your gut is right, a known block test only catches the big stuff, and for the little bends you're basically gambling on which direction the thing kissed a fixture last.
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