TIL Feeds and speeds charts are just a starting point

Was reading a post on Practical Machinist about a guy running a Micro 100 tool. He was running aluminum at 15,000 RPM with a .005 chipload. That's way faster than the book says. Shook my assumptions a bit. Any of you guys push past the recommended numbers regularly?

2 comments

2 Comments

paige_west10d ago

Honestly, have you checked tool deflection at those speeds?

the_emery10d agoOG Member

And actually @paige_west the deflection might not be the main issue here. On most newer spindles the real problem is the chip load dropping off as you increase rpm. Deflection matters more when you're already pushing the tool near its limit. Most people adjust speeds without thinking about what happens to the chip thickness per tooth. The material starts rubbing instead of cutting clean. That causes heat and tool wear that looks like deflection on the surface finish.