Old timer at the shop said my tool offsets were all wrong

I've been running CNC lathes for about 4 years now, and I always thought I had a good feel for setting tool offsets by eye. Then this guy with 30 years experience watched me set up a job and said 'you're leaving a full thou of inconsistency between tools.' He showed me how to use a test bar and a dial indicator to set each offset within half a tenth. Took me an extra 5 minutes per tool but my scrap rate dropped from like 5% to under 1% on the last batch of 500 parts. Has anyone else found that their manual setup was way off compared to what a gauge says?

3 comments

3 Comments

eric_knight721d ago

You can get repeatability down to half a tenth with a quality dial indicator if you take your time and watch the needle. I've done it myself with an Interapid and a test bar, so it's not some fantasy number the old timer pulled out of thin air. Maybe your indicator can't measure that fine, but plenty can.

tara79320d ago

@the_thea, I once saw a guy tram his vise with a tenths indicator and a magnetic base on a loose chip.

the_thea21d ago

Half a tenth? That's 50 millionths. Your indicator doesn't measure that fine.