A guy at a trade show in Cleveland made me rethink how I set up my work offsets

I was at the IMTS show last year, just walking the floor, and I stopped to watch a demo on a new Okuma lathe. The operator running it, an older guy with a shop shirt from Ohio, was showing how he sets his G54. Instead of just touching off the part, he explained he always takes a light cut first, measures that spot with a bore gauge, and then sets the offset based on that actual cut dimension. He said, 'Your tool might be off a thou from wear or the insert isn't seated perfect. The machine thinks it's at X, but the cut tells you where it really is.' I'd always just trusted the tool setter and the touch probe. Tried his method back at my shop on a tricky stainless job, and my size consistency got way better. Has anyone else moved to a 'cut, then set' method for critical work?

4 comments

4 Comments

kimr7428d ago

Oh man, that's wild. I had a buddy who worked at a tool and die shop back in the day, and he swore by that exact method for the tricky stuff. He used to tell me this story about a job they had, some fancy aerospace bracket, and the probe told them everything was perfect. But the first part was trash by like two thou because the probe was reading a tiny bit of dirt or something on the part. He said after that, the old timer in the shop made everyone do the cut-first method on any critical work, and they never scraped another part like that. It's one of those things where the extra minute feels like a pain until you realize it saves you from a whole afternoon of explaining yourself.

jana_jones3mo ago

Oh man, that hits home. I was SO confident in my probe until I scrapped a whole run of aluminum hubs. The tool was just barely pulling out of the holder, like half a thou. Now I do a "prove it" cut on the first part every time, especially after a tool change. It adds two minutes but saves a giant headache.

karen3613mo ago

Half a thou is all it takes to turn a hub into a very expensive paperweight. Your "prove it" cut is basically the machine shop version of poking a bear with a stick to make sure it's really asleep. Two minutes of paranoia beats eight hours of explaining to the boss why the scrap bin is full.

allen.kai3mo ago

Wait, half a thou? That's like... a tiny bit of dust. You're telling me that scrapes a whole part? I guess I've just never worked with stuff that tight. Seems like a lot of fuss for something you can barely even measure.