Warning: I just learned how much a single bad tool offset can cost in scrap

I was running a batch of 50 aluminum parts on our Haas VF2 last week, and the finish on the first pocket looked a bit off. I kept going, thinking it was just a tool mark. After checking the first five finished parts with a bore gauge, I found they were all undersize by about 0.003 inches. Turns out my Z offset for the 3/8 end mill was off by that exact amount from a tool change. That little mistake turned $200 worth of material into scrap in under an hour. Has anyone else had a small offset error wreck a whole job like that?

2 comments

2 Comments

brookewood1mo ago

Our shop started using tool presetters after a similar mess... it cut our scrap rate by half.

oscarwright1mo ago

You mentioned tool presetters cutting your scrap rate in half. That's a good step, but it's not a magic fix. A presetter only gives you the tool length off the machine. If you load that tool into a different holder, or if your tool setter probe on the Haas is out of calibration, you can still get a bad offset. We learned that the hard way after trusting the preset numbers too much. Now we always do a quick touch-off on the machine's probe for critical jobs, even with preset tools.