Old timer told me to check my backlash before any finish pass, ignored him for months

Back in February, this retired machinist named Hank kept saying check your backlash before every finish pass. I thought he was just old school and slow. Then I scrapped a $400 part because my table shifted 3 thou mid-cut. Took me two days to figure out what happened. Any of you guys actually check backlash every time or just when you feel something off?

2 comments

2 Comments

hernandez.brooke10d ago

Are you actually running that tight a tolerance that 3 thou is going to scrap a part? I mean, I get it if you're doing aerospace or something, but for most of us hobby guys checking backlash every pass just slows you down. I've been running my old Bridgeport for years and I only check it if the finish starts to look weird or I hear it chatter. You can usually feel when somethings off before it costs you a part.

gonzalez.vera10d ago

Oh man, yeah I feel that. I had a buddy who ran a little prototyping shop out of his garage, he was always skipping the backlash check on his old Lagun. One time he was cutting a fixture plate for a side job, thought he was golden. But the table shifted about 4 thou mid arc and he ended up with this weird wave in the surface. He had to grind the whole thing flat by hand over the weekend to save it. It was a real pain.